/

1991
Iowa
Turfgrass
Research
Report
\

»

t

IOWA STATE

FG-458 I July 1991

I

»

Introduction
N. E. Christians and M. L. Agnew

The following research report is the 11th annual publication of the results of turfgrass research projects
performed at Iowa State University. Copies of information in earlier reports are available from most of the
county extension offices in Iowa.
The 1990 season was a time of major renovation at the research area. Following the 1990 turf field day,
many of the older trials at the station were terminated and replaced by new studies. Among the new
trials established in the fall of 1990 were a new low-maintenance Kentucky bluegrass trial, a new highmaintenance Kentucky bluegrass trial, a new perennial ryegrass trial, a new green-height creeping
bentgrass trial, a new bermudagrass trial, and a new creeping bentgrass green for fungicide trials. The
irrigation system on another one acre of turf area was automated with a new Weather-Matic irrigation
system provided at a reduced cost by Weather-Matic Corporation and BH & L Irrigation of Lincoln,
Nebraska. The Toro irrigation system was updated with a new Network 8000 Satellite controller donated
by Toro Inc. and Tri-State Turf and Irrigation.
A new feature of this year’s research report is a section titled "Environmental Research". This section is
included to inform the public of our many research projects aimed at the environmental issues that face
the turf industry. In the past two years this has become a major thrust of the research program and many
of our more extensive, in-depth projects are now aimed at environmental issues.
We would like to acknowledge Richard Moore, manager of the turfgrass research area; Mark Stoskopf,
superintendent of the ISU Horticulture Research Station; Sue Kassmeyer, technical assistant; Doug
Campbell, technical assistant; and all others employed at the field research area in the past year for their
efforts in building the turf program.
Special thanks to Jane Punke and Barb Erickson for their work in typing and helping to edit this
publication.
Edited by Nick Christians, professor, Horticulture; Michael Agnew, associate professor, Horticulture.

Table of Contents
TURFGRASS RESEARCH AREA MAPS

1

ENVIRONMENTAL DATA

4

SPECIES AND CULTIVAR TRIALS
Results of Kentucky Bluegrass Regional Cultivar Trials - 1990

6

Regional Perennial Ryegrass Cultivar Evaluation

11

Fine Fescue Management Study

13

Tall Fescue Cultivar Trial

15

Tall Fescue Management Study

17

Shade Adaptation Study

18

Fairway Height Bentgrass Study - 1990

20

Fairway Height Kentucky Bluegrass Trial - 1990

21

HERBICIDE STUDIES
Preemergence Annual Weed Control Study - 1990

23

Postemergence Annual Grass Control Study - 1990

25

Broadleaf and Postemergence Annual Weed Control Study - 1990

28

Broadleaf Weed Control Study - 1990

30

Effects of Dithiopyr (Dimension) on the Rooting of Creeping Bentgrass

32

1990 Sod Rooting Trial

34

The Effect of Prograss on the Establishment of Cool-Season Grasses

37

Poa annua Control with Ethofumesate on Veenker Golf Course

39

Fairway Height Bentgrass Response to Fenoxaprop

40

TURFGRASS DISEASE RESEARCH
The Response of Kentucky Bluegrass Turf to Mefluidide Applied in Combination
with Fungicides and Other Compounds

43

Evaluation of Fungicides for Control of Leaf Spot on Park Kentucky Bluegrass

45

Evaluation of Fungicides for Control of Snow Molds on Creeping Bentgrass 1990-91

47

Evaluation of Fungicides for Control of Dollar Spot on Emerald Bentgrass - 1990

49

INSECTS
Report of Insecticide Evaluation

51

Controlling Adult Bluegrass Billbugs in KentuckyBluegrass

54

STRESS STUDIES AND FERTILIZER TRIALS
CORON Research at Iowa State University

56

Natural Organic Trial

64

The Effects of 13 Granular Nitrogen Fertilizer Sources on the Growth and
Quality of ’Park’ Kentucky Bluegrass

67

The Effects of Synthetic and Natural Organic Nitrogen Source and Core
Cultivation on Turfgrass Growth Under Traffic Stress

70

The Evaluation of 13 Granular Nitrogen Sources on the Quality of
Bentgrass Greens

77

The Effects of Core Cultivation on the Performance of Four Nitrogen Fertilizers

80

Comparison of Kentucky Bluegrass Response to Agriform, IBDU, Sulfur Coated Urea,
and Urea
83
MURP Studies

90

ORNAMENTALS AND MISCELLANEOUS
Crabapples

99

Weed Control With Landscape Fabrics

107

Shade and Flowering Tree Evaluation

112

NCR-10 Regional Alternative Grass Trial

114

Selective Control of Quackgrass With Primisulfuron

119

1990 Bedding Plant Field Trial

124

Ornamental Grass Studies - 1990

128

ENVIRONMENTAL RESEARCH
Non-Target Movement of Herbicides Applied to Turfgrass Areas

132

Isolation and Identification of Allelopathic Compounds

133

Evaluation of Species of Pseudomonas and Streptomyces as Potential
Biocontrol Agents for Dollar Spot and Leaf Spot

133

Physiological Management of Chlorosis Associated with Foliar
Pathogens of Turfgrasses

134

Plant and Soil Response to Nitrogen Fertilizer Source

134

Allelopathic Effects of Several Torpenoids on Plant Growth

135

Organic Lawn Care Trial

136

Pesticide and Fertilizer Fate in Turfgrasses Managed under Golf Course
Conditions in the Midwestern Region

136

INTRODUCING
The Iowa State University Personnel affiliated with the Turfgrass Research Program
COMPANIES AND ORGANIZATIONS that made donations or supplied products to the
Iowa State University TurfgrassResearch Program

138

140

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1984 Expansion of the Turfgrass Research Area
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II

Results of Kentucky
Bluegrass Regional Cultivar Trials - 1 9 9 0
N.E. Christians

The United States Department of Agriculture (USDA) has initiated several regional Kentucky bluegrass
cultivar trials that are currently being conducted at most of the northern agricultural experiment
stations. The test consists of either 80 or 84 cultivars; the number depending on the year the trials
were initiated, with each cultivar replicated three times.
Two trials were underway at Iowa State University during the 1990 season. The oldest is a highmaintenance study established in 1981 that receives 4 lb nitrogen (N)/1000 ft2/yr and is irrigated as
needed. The second trial was established in 1985 and receives 4 lb N/1000 ir/yr, but is not irrigated.
The objective of the high-maintenance study is to investigate the performance of the 84 cultivars under
a cultural regime similar to that used on irrigated home lawns in Iowa. The objective of the second
study is to observe the response of 80 cultivars under conditions similar to those found in nonirrigated
lawns that receive a receiving standard lawn care program.
The values listed under each month in Tables 1 and 2 are the averages of ratings made on three
replicated plots for the two studies. Yearly means of data from each month were taken and are listed
in the last column. The first cultivar received the highest average rating for the entire 1990 season.
The cultivars are listed in descending order of average quality.
The high maintenance irrigated trial (Table 1) was terminated in July 1990 after 9 years. A new, larger
USDA trial was seeded in the fall of 1990. ’Ram I’ was the highest rated cultivar in 1990. Other wellknown varieties that performed well in this extremely wet year were ’Welcome’, ’Sydsport’, ’Fylking'
and ’Rugby’.
The nonirrigated, high-maintenance trial (Table 2) was much like an irrigated study because of the
rainfall in 1990. Common varieties that performed well in the drought years of 1988 and 1989, such
as ’Kenblue’ and ’South Dakota Cert.’, also received high ratings in 1990. This was probably due to
the advantage these varieties maintained in the drought years and carried with them into the spring of
1990. The common varieties often decrease in quality in wet years due to disease development. This
was not observed in 1990.

6

Cultivar

May

June

July

RAM-1
239
MLM-18011
WELCOME
N535
SYDSPORT
ENOBLE
GLADE
FYLKING
KIMONO
RUGBY
WW AG 480
BONO
SHASTA
BRISTOL
NUGGET
PSU-190
PSU-173
PARADE
WW AG 478
1-13
MER PP 300
ESCORT
BARON
ENMUNDI
SV-01617
TOUCHDOWN
VANESSA
1528T
ECLIPSE
TRENTON
WW AG 463
MOSA
MERIT
COLUMBIA
MONA
VICTA
S.D. COMMON
BA-61-91
BARBLUE
243
WABASH
PSU-150
PLUSH
HARMONY
MAJESTIC
A20-6
NJ 735
225
K3-179

7.7
7.0
7.0
7.0
7.3
7.0
7.0
6.7
7.0
7.3
7.0
6.7
6.3
7.0
7.0
7.0
7.0
7.0
6.7
6.7
7.7
7.0
6.7
7.0
6.7
6.7
7.0
7.0
6.7
6.3
7.0
6.0
6.7
6.7
7.0
6.3
6.7
6.7
6.3
7.0
6.3
6.3
6.7
6.3
6.3
6.0
7.3
6.7
7.0
7.0

8.0
8.0
7.3
7.3
7.0
7.0
7.3
7.0
7.3
7.7
7.3
7.7
7.7
7.3
7.3
6.7
7.3
7.0
7.0
7.3
6.7
7.7
7.0
7.0
7.0
7.0
7.3
6.7
7.7
7.0
6.7
7.3
6.7
7.0
6.7
6.7
6.7
7.0
7.3
6.7
7.0
7.3
7.0
6.3
7.0
7.3
7.0
7.0
6.0
6.7

8.0
7.3
7.7
7.7
7.7
8.0
7.7
8.0
7.3
6.7
7.3
7.3
7.7
7.3
7.3
7.7
7.0
7.3
7.7
7.3
7.0
6.7
7.7
7.0
7.3
7.3
6.7
7.3
6.7
7.7
7.0
7.3
7.3
7.0
7.0
7.7
7.3
7.0
7.0
7.0
7.0
6.7
6.7
7.7
7.0
7.0
6.0
6.7
7.3
6.7

7

Mean
7.9
7.4
7.3
7.3
7.3
7.3
7.3
7.2
7.2
7.2
7.2
7.2
7.2
7.2
7.2
7.1
7.1
7.1
7.1
7.1
7.1
7.1
7.1
7.0
7.0
7.0
7.0
7.0
7.0
7.0
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
00

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.

The 1990 quality ratings for the high-maintenance regional Kentucky bluegrass test that
was established in the fall of 1981.

ON

Table 1.

Table 1.

51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.

The 1990 quality ratings for the high-maintenance regional Kentucky bluegrass test that
was established in the fall of 1981. (c o n tin u e d )

Cultivar

May

June

July

Mean

K3-178
MONOPOLY
BANFF
DORMIE
CEB VB 3965
KENBLUE
CELLO
PIEDMONT
A20
A-34
SH-2
BIRKA
CHERI
S-21
GERONIMO
ASPEN
CHARLOTTE
A20-6A
APART
MER PP 43
VANTAGE
H-7
LOVEGREEN
P141 (MYSTIC)
K3-152
HOLIDAY
BONNIEBLUE
BAYSIDE
ADMIRAL
K3-162
ADELPHI
AMERICAN
ARGYLE
MERION

6.7
7.0
6.3
6.7
6.3
6.0
7.3
6.7
6.7
7.0
6.7
7.0
6.7
7.0
6.7
6.3
6.0
6.3
6.0
5.7
6.7
6.3
6.0
6.3
5.7
6.7
6.0
6.3
6.0
6.0
6.7
5.7
6.0
6.0

7.0
6.3
6.7
6.7
7.0
6.3
6.7
6.3
7.0
6.7
6.3
6.3
6.7
6.0
6.7
6.7
6.7
7.0
6.3
7.0
6.0
6.7
6.7
6.7
7.0
6.0
6.3
6.3
6.3
6.3
5.3
6.3
5.7
6.0

6.7
6.7
7.0
6.7
6.7
7.7
6.0
7.0
6.3
6.3
7.0
6.3
6.3
6.7
6.3
6.7
7.0
6.3
7.3
7.0
6.7
6.3
6.7
6.3
6.7
6.3
6.7
6.3
6.7
6.7
6.7
6.3
6.7
6.3

6.8
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.6
6.6
6.6
6.6
6.6
6.6
6.6
6.6
6.6
6.4
6.4
6.4
6.4
6.4
6.3
6.3
6.3
6.3
6.3
6.2
6.1
6.1
6.1

8

Table 2.

The 1990 quality ratings for the high-maintenance regional Kentucky bluegrass test that
was established in the fall of 1981.

Cultivar

May

June

July

Aug

Sept

Mean

i.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.

7.3
6.7
6.3
6.5
6.3
6.7
6.3
6.7
5.7
6.0
4.7
6.7
5.7
5.7
5.7
6.3
5.0
5.7
6.3
7.0
6.3
4.7
5.3
5.3
6.3
4.7
4.3
5.0
6.0
5.3
5.0
5.0
4.0
5.0
4.7
4.3
5.3
5.3
4.7
4.7
4.0
5.7
5.3
5.0
4.3
5.0
4.3
5.3
4.7
4.0
5.0

7.0
5.7
7.0
6.0
6.7
7.0
6.7
7.0
6.7
6.7
5.7
6.0
6.7
6.7
6.0
5.3
6.3
6.0
6.0
6.0
6.3
5.7
5.7
6.3
6.7
5.7
6.7
6.0
6.3
5.3
6.0
5.7
6.0
6.0
6.3
6.0
5.7
6.0
4.7
5.7
5.5
5.7
6.7
5.3
6.0
6.0
5.0
5.7
5.3
6.0
6.0

7.3
8.3
7.7
8.0
7.7
7.7
8.0
7.3
7.0
7.3
7.7
7.0
7.3
7.3
7.3
6.0
7.3
7.0
6.7
6.3
6.7
7.3
6.7
6.7
6.7
7.7
7.3
6.3
6.7
6.7
6.3
6.3
6.7
6.3
6.3
6.7
7.3
6.7
7.0
6.3
6.8
6.7
6.3
6.0
6.3
6.0
7.7
6.0
7.0
6.3
6.3

8.0
8.3
7.3
7.5
7.0
6.3
6.3
7.0
7.3
7.0
7.0
6.3
7.0
7.0
6.3
7.3
7.3
6.7
7.3
6.3
7.0
7.3
7.7
6.7
6.0
7.0
6.3
6.7
6.0
6.7
6.3
7.0
7.0
6.7
6.7
7.0
7.0
6.3
6.7
7.3
7.5
6.3
5.7
6.7
6.7
6.0
6.0
6.3
6.3
6.3
5.7

6.0
6.0
6.0
6.0
6.3
5.7
6.3
5.0
5.7
5.3
6.3
5.3
5.0
5.0
5.7
6.0
4.7
5.0
4.3
5.0
4.3
5.3
5.3
5.0
4.0
4.3
4.7
5.3
4.3
5.3
5.7
5.0
5.3
5.0
5.0
5.0
3.7
4.7
5.7
4.3
4.8
4.3
4.3
5.3
5.0
5.3
5.0
4.7
4.3
4.7
4.7

7.1
7.0
6.9
6.8
6.8
6.7
6.7
6.6
6.5
6.5
6.3
6.3
6.3
6.3
6.2
6.2
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.0
5.9
5.9
5.9
5.9
5.9
5.9
5.9
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.7
5.7
5.7
5.7
5.7
5.7
5.7
5.7
5.6
5.6
5.5
5.5
5.5

WABASH
JOY
GEORGETOWN
MONOPOLY
KENBLUE
SOUTH DAKOTA CERT.
PARK
A-34
SOMERSET
NASSAU
MYSTIC
HUNTSVILLE
TRENTON
NE 80-30
IKONE
NE 80-14
ABLE I
NE 80-88
LOFTS 1757
JULIA
F-1872
BLACKSBURG
WW AG 495
RUGBY
CLASSIC
P-104
BAR VB 534
CYNTHIA
PARADE
DESTINY
K3-178
RAM-I
BA 73-626
ASSET
ECLIPSE
GLADE
HARMONY
NE 80-50
TENDOS
LIBERTY
AMAZON
239
AQUILA
Kl-152
WW AG 491
NE 80-47
AMERICA
PST-CB1
BARZAN
HAGA
BARON

9

Table 2.

The 1990 quality ratings for the high-maintenance regional Kentucky
bluegrass test that was established in the fall of 1981.(continued)

Cultivar

May

June

July

Aug

Sept

Mean

52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.

CONNI
BA 70-242
BA 72-441
BA 73-540
NE 80-48
BA 72-492
SYDSPORT
WW AG 468
WW AG 496
NE 80-55
MERIT
BA 70-139
BA 69-82
HV 97
MIDNIGHT
NE 80-110
ANNIKA
BRISTOL
VICTA
BA 72-500
DAWN
MERION
WELCOME
COMPACT
CHERI
ASPEN
GNOME
BAR VB 577
CHALLENGER

5.0
4.3
4.0
4.0
4.0
5.0
4.0
3.7
4.0
5.3
5.0
4.0
4.0
3.3
3.3
5.0
4.0
4.3
4.0
4.0
5.3
3.7
4.3
4.3
3.7
3.3
4.3
4.0
4.3

5.3
6.0
5.7
6.0
5.3
5.3
5.3
5.0
6.0
5.3
5.0
5.3
5.3
5.7
5.3
5.7
5.3
5.0
5.3
5.0
5.7
5.0
5.7
5.0
5.3
5.0
4.7
5.3
4.7

6.7
6.3
6.3
6.7
6.7
5.7
6.0
6.7
6.7
5.7
6.0
5.7
6.0
6.0
6.3
5.7
6.0
6.0
6.0
5.3
5.7
6.0
5.7
5.0
6.0
6.3
5.3
5.3
5.3

6.3
6.7
6.7
6.7
7.0
6.3
6.0
6.3
6.0
5.7
6.0
6.3
6.0
6.7
6.0
5.3
6.0
6.3
6.3
6.3
5.3
6.7
5.3
5.7
5.3
5.7
5.3
5.0
5.7

4.3
4.3
4.7
4.3
4.7
4.7
5.0
5.0
4.0
4.3
4.0
4.7
4.7
4.3
5.0
4.3
4.3
3.7
3.7
5.0
3.7
4.3
4.3
4.3
4.0
4.0
4.3
4.0
3.3

5.5
5.5
5.5
5.5
5.5
5.4
5.3
5.3
5.3
5.3
5.2
5.2
5.2
5.2
5.2
5.2
5.1
5.1
5.1
5.1
5.1
5.1
5.1
4.9
4.9
4.9
4.8
4.7
4.7

LSD 0.05

1.6

1.3

1.5

NS

1.5

3.0

Quality based on a scale of 9 to 1: 9 = best quality, 6 - acceptable quality,
and 1 = poorest quality.

10

Regional Perennial Ryegrass Cultivar Evaluation
R. W. Moore and N. E. Christians

This was the eighth and final year of data from this trial established in the fall of 1982. It was
established in conjunction with several identical trials across the country coordinated by the USDA. The
purpose of the trial was to identify regional adaptation of 48 perennial ryegrass cultivars. Cultivars were
evaluated for turf quality each month of the growing season through August when the study was
terminated.

2

The trial was maintained at a 2 in mowing height with 3 to 4 lb N/1000 ft through the growing season
and irrigated when needed to prevent drought. Preemergence herbicide is applied once in the spring
and broadleaf herbicide was applied once in September to control weeds. This trial received record
rainfall during the 1990 season.
There were no statistical differences among the first 16 cultivars in Table 3. Notice that several of the
top performers in 1990 were experimental numbered cultivars. Several of these numbered cultivars have
rated in the top 20 each of the past few years. A considerable amount of breeding and selection of
perennial ryegrasses has been conducted in the past decade and a number of new releases of welladapted cultivars can be expected in the future. Some of these numbered cultivars have been given
names.
It is interesting to note that “Manhattan II“ and “Manhattan“, cultivars that performed well in this trial in
past years, received low ratings in 1990. This was likely due to the very wet conditions.

11

Table 3. Turf quality of perennial ryegrass cultivars in 1990

Cultivar
1. BIRDIE
2. SWRC-l
3. 2EE (Cowboy)
4.
282 (Citation II)
5. IA 728 (Allstar)
6. PALMER
7. LP 210
8. ACCLAIM
9. GT-II (Repell)
10.
ELKA
11. . PRELUDE
12. LP 702 (Mondial)
13. WWE 19
14. HR-1
15. DELRAY
16. REGAL
17. FIESTA
18. NK 79309
19. PENNANT
20. BLAZER
21.
2ED (Birdie II)
22. CROWN
23. HE 178
24. DASHER
25. BT-I (Tara)
26. HE 168
27. CUPIDO
28. DERBY
29. DIPLOMAT
30. RANGER
31. COCKADE
32. OMEGA
33. NK 79307
34. GATOR
35. LP 736 (Ovation)
36. LP 792
37. PREMIER
38. CIGIL
39. MANHATTAN II
40. NK 80389
41. M382
42. PENNFINE
43. BARRY
44. YORKTOWN II
45. CITATION
46. LINN
47. MANHATTAN
48.
PIPPIN
LSD 0.05

April

May

Ratings5
June

July

6.3
5.7
5.7
5.7
5.3
5.3
6.0
5.7
5.3
5.7
5.3
5.0
5.3
5.3
5.0
5.0
5.0
5.3
5.0
5.0
5.0
5.3
5.0
4.7
4.7
4.0
5.0
4.7
4.3
4.3
5.0
4.7
4.3
5.0
4.3
4.3
4.0
4.7
4.3
4.7
4.3
4.0
4.3
4.3
4.3
4.0
4.3
4.3

7.3
6.7
6.7
6.7
6.3
6.3
6.7
6.7
6.3
6.7
6.3
6.0
6.3
6.3
6.0
6.0
6.0
6.0
6.0
5.7
5.7
6.3
6.0
5.7
5.7
5.0
6.0
5.7
5.3
5.0
5.7
5.3
5.0
6.0
5.3
5.3
5.0
5.3
5.3
5.0
5.0
4.7
4.7
4.7
4.3
4.3
5.0
5.3

6.7
7.0
6.7
7.0
7.0
7.0
6.7
6.3
6.3
6.3
6.3
6.7
6.7
6.7
6.3
6.3
6.3
6.0
6.0
6.3
6.3
6.0
6.0
5.7
6.3
6.0
5.7
6.0
6.0
6.3
5.7
6.0
6.3
6.0
6.0
5.7
6.0
5.7
5.3
5.3
5.7
6.0
5.3
5.3
5.3
5.7
5.0
5.0

7.3
7.3
7.3
7.0
7.3
7.0
7.0
7.0
7.7
6.7
7.3
7.3
7.0
6.7
7.0
7.0
6.7
6.7
7.0
6.7
6.7
6.0
6.3
7.0
6.7
7.0
6.3
6.7
6.7
6.7
6.3
6.7
6.7
6.3
6.0
6.3
6.3
6.0
6.3
6.0
6.3
6.D
6.0
5.3
6.0
6.0
5.7
5.3

7.7
7.7
7.7
7.7
8.0
7.7
7.3
7.7
8.0
7.7
7.3
7.7
7.0
7.7
7.7
7.7
7.3
7.3
7.7
7.3
7.3
6.7
7.0
7.3
7.0
8.0
7.0
7.0
7.3
7.0
7.0
7.0
7.3
6.3
7.0
7.0
7.0
6.3
6.7
6.7
6.3
6.7
6.7
6.7
6.7
6.7
6.0
5.7

7.1
6.9
6.8
6.8
6.8
6.7
6.7
6.7
6.7
6.6
6.5
6.5
6.5
6.5
6.4
6.4
6.3
6.3
6.3
6.2
6.2
6.1
6.1
6.1
6.1
6.0
6.0
6.0
5.9
5.9
5.9
5.9
5.9
5.9
5.7
5.7
5.7
5.6
5.6
5.5
5.5
5.5
5.4
5.3
5.3
5.3
5.2
5.1

1.6

1.9

1.0

1.3

1.0

1.1

Aug

a Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable
quality, and 1 = poorest quality.

12

Mean

Fine Fescue Management Study

N. E. Christians and R. W. Moore

The fine fescue management study includes the following cultivars:
1.
2.
3.
4.
5.

Pennlawn Red Fescue
Scaldis Hard Fescue
Ruby Red Fescue
Atlanta Chewings Fescue
K5-29 Red Fescue

6.
7.
8.
9.
10.

Dawson Red Fescue
Reliant Hard Fescue
Ensylva Red Fescue
Highlight Chewings Fescue
Jamestown Chewings Fescue

Each cultivar was maintained in full sun at two mowing heights: 1 and 2 in. Each plot was divided into
two fertilizer treatments: 1 and 3 lb N/1000 ft2 applied as IBDU. The area was irrigated as needed. The
study was established on September 8, 1979, and was the oldest study in the turf research area before
it was terminated in August 1990.
The quality ratings in Table 4 are the means of monthly ratings taken on replicated plots from May to
August. ’Reliant’ and ’Scaldis’ hard fescue had the best overall quality in 1990 and through all of the
years the study was conducted.
These cultivars performed satisfactorily even under the extreme conditions of a 1 in mowing height and
1 lb N/1000 ft2/year. They have performed consistently well for the 12 years the trial has been in place.
They also have shown excellent disease tolerance, whereas many of the other grasses have been
observed to be quite susceptible to Dollar Spot.
’Jamestown’ and ’Atlanta Chewings’ fescue also performed well in 1990. ’Highlight’ chewings fescue
performed very poorly. Generally, the creeping red fescues did not perform well during the 12 years of
the study.

13

Table 4. The effects of mowing height and nitrogen fertilizer on the quality of 10 fine fescues in 1990.

_____ Mowing Height_____
1 in
2 in
N Rate
N Rate
1 lba
3 lb
1 lb
3 lb
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.

Pennlawn Red Fescue
Scaldis Hard Fescue
Ruby Red Fescue
Atlanta Chewings Fescue
K5-29 Red Fescue
Dawson Red Fescue
Reliant Hard Fescue
Ensylva Red Fescue
Highlight Chewings Fescue
Jamestown Chewings Fescue

5.4b ’c
6.6
4.4
5.8
4.4
5.0
6.4
5.4
3.6
6.2

5.0
6.7
4.9
5.8
4.3
5.0
6.6
4.8
3.2
6.5

5.8
6.8
5.4
6.3
5.1
5.7
6.7
6.5
4.3
6.3

5.8
7.0
6.0
6.3
5.3
6.2
6.8
5.9
3.5
6.7

Overall
Mean
5.5
6.8
5.2
6.0
4.8
5.5
6.6
5.7
3.6
6.4

-------------------------------- --------------------------------------------a N rates are in lb N/1000 ft /yr. The N source was IBDU.
k Values are the means of monthly observations from May to October.
c Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable
quality, and 1 = poorest quality.

14

J

Tall Fescue Cultivar Trial
M. L. Agnew and N. E. Christians

The 65 tall fescue cultivars were established in the fall of 1987 at the Iowa State University Horticulture
Research Station. The study was maintained at a 2-in mowing height and fertilized with 2 lb N/1000 ft2/yr.
The area was unirrigated and receives no fungicide or insecticide applications.
The data in Table 5 reflects the harsh summer of 1989. Rainfall was short and quality ratings were low.
’Normarc 25’ and ’Shenandoah’ were the only tall fescue cultivars to have a mean rating over 7. Most
cultivars had a mean quality over the acceptable leval of 6.

Table 5. Quality data for tall fescue cultivar trial.
Cultivar

Apr

May

June

July

Aug

Sept

Mean

1. NORMARC 25
7.3
2. PE-7E
7.3
(Shenandoah)
3. HUBBARD 87
7.0
4. MESA
6.7
5. FALCON
6.7
6. JAGUAR II
6.3
7. TRIBUTE
7.0
8. CAREFREE
7.0
9. FINELAWN I
7.3
10. NORMARC 99
7.0
6.7
11. PICK 845PN
(Guardian)
12. PST-5AP
7.3
13. PST-DBC
6.7
14. WILLAMETTE
7.0
15. FATIMA
6.7
16. FINELAWN 5GL 7.0
17. JAGUAR
7.0
18. PST-5DM
6.7
19. KWS-DUR
6.0
20. MONARCH
6.7
21. APACHE
6.7
22. BAR FA 7851
6.3
(Barnone)
23. JB-2
6.7
24. PST-5MW
6.7
25. THOROUGHBRED 7.0
26. TRAILBLAZER
6.7
27. WRANGLER
6.7
28. CIMMARON
6.3
29. LEGEND
6.3
30. OLYMPIC
6.7

8.0
7.3

7.3
7.0

6.0
6.7

6.7
5.3

7.7
8.3

7.2
7.0

8.0
6.3
7.0
7.0
6.7
6.8
6.7
7.3
7.3

7.0
7.7
6.3
7.0
6.3
7.0
6.3
5.7
6.7

5.3
6.0
6.0
5.7
6.0
6.0
6.0
5.7
4.7

6.3
7.0
7.0
6.3
7.0
6.3
6.0
6.0
6.3

7.7
7.7
7.7
8.3
8.0
7.3
8.0
8.7
8.3

6.9
6.9
6.8
6.8
6.8
6.7
6.7
6.7
6.7

7.3
7.3
7.0
6.3
6.0
6.7
7.0
7.0
7.7
7.3
6.7

6.0
6.3
6.3
6.3
6.7
6.3
6.0
6.3
5.3
5.3
6.3

5.3
5.3
6.0
6.0
5.7
5.3
5.7
5.3
4.7
5.3
5.0

6.7
6.7
6.3
6.7
6.3
6.3
6.3
6.3
6.3
6.0
6.0

7.7
8.0
7.7
7.7
7.7
8.0
7.7
8.0
8.3
8.0
8.0

6.7
6.7
6.7
6.6
6.6
6.6
6.6
6.5
6.5
6.4
6.4

6.7
8.0
6.7
6.7
7.0
6.7
7.3
6.3

6.0
6.0
5.3
6.7
6.3
5.3
5.0
6.0

6.0
5.0
5.7
4.7
4.7
5.3
5.3
5.0

6.0
5.7
6.0
6.7
6.0
6.3
6.3
6.3

7.3
7.3
7.7
7.0
8.0
7.7
7.3
7.7

6.4
6.4
6.4
6.4
6.4
6.3
6.3
6.3

15

Table 5.

Quality data for tall fescue cultivar trial (continued).
Apr

May

June

July

Aug

Sept

Mean

TIP
6.7
TITAN
7.0
ADVENTURE
6.7
ARID
6.7
7.0
PE-7
PICK DM
5.7
(Avanti)
PST-5D1
6.0
(Eldorado)
PST-5EN
6.3
REBEL
6.7
REBEL II
6.0
SYN GA
6.7
TRIDENT
6.7
KY-31
6.3
PACER
6.3
PICK GH6
6.3
(Maverick II)
PST-5F2
6.3
(Winchester)
RICHMOND
6.3
TAURUS
6.3
AZTEC
5.3
BEL 86-1
6.3
NORMARC 77
6.3
PICK TF9
5.7
(Crossfire)
PST-5HF
5.7
(Amigo)
SUNDANCE
5.7
6.0
PICK 127
(Cochise)
PST-50L
6.0
BEL 86-2
5.3
BONANZA
5.3
KWS-BG-6
5.0
(Twilight)
PICK SLD
4.7
(Emperor)
PST-5D7
3.3
(Murietta)
CHIEFTAIN
5.0
PST-5BL
5.0
(Silverado)
PICK DDF
4.0
(Shortstop)
PST-5AG
4.7

6.0
7.0
7.0
6.0
7.7
7.3

6.3
5.0
5.3
6.3
5.3
6.0

5.3
5.0
5.3
5.0
4.3
4.7

6.0
6.0
5.7
5.7
5.7
5.7

7.7
8.0
7.3
7.3
7.0
7.7

6.3
6.3
6.2
6.2
6.2
6.2

7.0

6.0

4.7

6.0

7.3

6.2

6.7
7.0
6.7
6.3
6.0
6.7
6.0
7.0

5.7
6.0
6.3
5.7
6.0
5.0
6.0
5.3

5.0
4.7
5.0
5.0
4.7
5.3
5.3
4.3

6.0
5.7
6.0
5.7
6.3
6.3
6.0
5.7

7.7
7.3
7.0
7.7
7.7
6.7
7.0
8.0

6.2
6.2
6.2
6.2
6.2
6.1
6.1
6.1

6.0

5.3

4.3

6.3

8.0

6.1

6.3
7.3
8.0
7.0
7.0
8.0

5.0
5.7
5.7
4.7
5.3
5.3

5.7
4.3
4.7
4.7
4.3
4.3

6.3
5.7
5.0
5.3
5.7
5.3

7.0
7.3
7.0
7.3
6.7
7.0

6.1
6.1
5.9
5.9
5.9
5.9

7.7

5.7

4.3

5.3

7.0

5.9

6.3
7.3

5.0
4.7

5.0
4.0

6.0
5.7

7.7
7.3

5.9
5.8

6.3
7.3
7.0
7.7

5.7
5.3
5.0
5.7

4.3
4.7
4.3
2.7

6.0
5.0
5.7
5.0

6.7
6.7
6.7
6.7

5.8
5.7
5.7
5.6

7.0

5.3

4.3

5.7

6.7

5.6

7.3

6.0

4.3

5.0

7.3

5.6

6.3
7.3

5.0
4.7

4.3
4.3

5.0
5.3

7.3
6.0

5.5
5.4

6.7

4.7

4.0

5.7

7.0

5.3

6.3

4.3

4.0

4.7

6.3

5.1

Cultivar
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.

Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and
1 = poorest quality.

16

Tall Fescue Management Study
R. W. Moore and N. E. Christians

This report contains the seventh year of data from this experiment. The experiment was designed to
compare the response of ’Falcon’, ’Houndog’, ’Kentucky 31’, ’Mustang’, and ’Rebel’ tall fescue at 0, 2,
and 4 lb N/1000 fr /y r and cutting heights of 2 and 3 in. One pound of N was applied once during
May and September for the 2 lb treatment and during April, May, August, and September for the 4 lb
treatment. In the strip-split plot arrangement, all six combinations of the two management factors are
placed in a 2 ft by 3 ft block within each cultivar with the five cultivars replicated three times.
There was little difference between the 3 in cut and the 2-in cut in overall turf quality for all cultivars
(Table 6). Turf quality increased with each increment of N for all of the cultivars at both mowing
heights. The cultivars responded in a very similar way to the variations in mowing height and fertility
in 1990. In general, each of the cultivars performed well through the season. None of the new
varieties were observed to be superior to the older Kentucky-31.
Table 6. Turf quality of tall fescue cultivars at two clipping heights and three fertility levels.
Clip
ht
inch

Ratingsa

lb N/
10§°
May

June

July

Aug

Sept

Mean

0
2
4
0
2
4
0
2
4
0
2
4
0
2
4
0
2
4
0
2
4
0
2
4
0
2
4
0
2
4

3.3
6.0
7.7
3.3
4.3
8.0
3.3
6.0
8.0
5.3
6.7
6.7
3.3
4.7
6.7
3.0
5.0
7.3
3.3
5.3
7.0
3.7
6.0
8.0
3.3
5.3
7.3
3.7
5.3
8.0

3.0
5.7
7.7
3.0
6.0
7.7
3.7
6.3
7.7
4.7
6.3
6.7
3.3
6.3
7.7
3.3
6.0
7.7
3.3
5.7
7.7
3.3
6.0
7.7
3.7
5.7
7.3
3.3
6.0
7.7

3.7
5.7
7.3
3.7
6.0
7.3
4.3
6.3
7.7
4.7
6.3
7.0
3.7
5.3
7.3
4.0
5.7
8.0
3.7
6.0
7.7
4.7
6.0
8.0
4.7
5.7
7.3
4.0
6.0
7.7

4.0
6.0
7.3
3.7
6.7
8.0
4.3
5.3
7.3
5.7
6.0
7.3
3.7
5.0
7.3
4.3
5.7
8.0
4.0
6.3
7.7
4.7
6.7
8.0
4.7
5.7
7.0
4.3
6.0
7.7

4.7
6.3
8.0
5.0
6.7
7.3
5.3
6.3
7.7
6.0
6.7
7.0
5.0
6.3
7.7
5.3
6.3
8.0
5.0
6.3
8.0
5.0
6.3
8.0
5.7
6.0
7.7
5.7
6.0
7.0

3.7
5.9
7.6
3.7
5.9
7.7
4.2
6.1
7.7
5.3
6.4
6.9
3.8
5.5
7.3
4.0
5.7
7.8
3.9
5.9
7.6
4.3
6.2
7.9
4.4
5.7
7.3
4.2
5.9
7.6

LSD cultivar averages
LSD fertilizer treatments

0.3
0.5

0.5
0.5

1.1
0.7

1.0
0.5

1.3
0.7

0.6
0.5

Cultivar
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.

REBEL
REBEL
REBEL
REBEL
REBEL
REBEL
MUSTANG
MUSTANG
MUSTANG
MUSTANG
MUSTANG
MUSTANG
KENTUCKY-31
KENTUCKY-31
KENTUCKY-31
KENTUCKY-31
KENTUCKY-31
KENTUCKY-31
HOUNDOG
HOUNDOG
HOUNDOG
HOUNDOG
HOUNDOG
HOUNDOG
FALCON
FALCON
FALCON
FALCON
FALCON
FALCON

2
2
2
3
3
3
2
2
2
3
3
3
2
2
2
3
3
3
2
2
2
3
3
3
2
2
2
3
3
3

a Quality based on a scale of 9 to 1: 9
quality, and 1 = poorest quality.

17

=

best quality, 6 = acceptable

Shade Adaptation Study
N. E. Christians

The shade adaptation study was established in the fall of 1987 to evaluate the performance of 35
species and cultivars of grasses. The species include creeping red fescue (C.R.F.), hard fescue
(H.F.), tall fescue (T.F.), Kentucky bluegrass (K.B.), and rough bluegrass (Poa trivialis).
The area is located under the canopies of a mature stand of Siberian elm trees (
pumila) at the
Iowa State University Horticulture Research Station. The grasses were mowed at a 2- in height and
received 2 lb N/1000 ft2/year. No weed control has been required on the area. The area was irrigated
during extended droughts.
Monthly quality data was collected from May through September. Several of the hard fescues (H.F.)
and ‘Estica’ creeping red fescue (C.R.F.) were the best performers in 1990 (Table 7). These were
followed by the tall fescues, many of which maintained very good quality all season long. None of the
Kentucky bluegrasses maintained an acceptable quality. In general, the Kentucky bluegrasses were
the poorest quality grasses in this study.

18

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fa fa fa w s 2 O fa! i— i fa H fal M H <q <
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2.
3.
4.
5.

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fa
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fa
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1.

Table 7. Turf quality ratings of shade trial in 1990 (seeded fall 1987).

fa

fa fa
fa
*5~!
fa
fa
<C U fa 53 O<C H
< fa<! fa
<2 53
>

fa

fa

fa

53 2
> 2
2;
fa
fa 53 u e> <c O fa fa <r
P

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fa
fa o Q i—i W
fa fa 2 fa fa
2

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19

i-i

m
o
o

Q
faco

Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality, and 1 = poorest quality.

c
Cti

Fairway Height Bentgrass Study -19 90

N. E. Christians

The fairway height bentgrass study was established in the fall of 1988 to compare the response of several
new cultivars of seeded bentgrasses with the older types. The grass was kept at an 0.5 in mowing height,
the standard mowing height for creeping bentgrass fairways. The area received liquid applications of urea
as needed during the season (0.2 lb N/1000 fr/application in 3 gal water/1000 ft2). The total N application
rate is approximately 3 lb/season. Fungicides and insecticides were used as needed. The area was
irrigated as needed, but little irrigation was required until August because of the high rainfall in 1990.
The best cultivars in 1989 were ’SR 1020’ and ’Penneagle’ (see 1990 research report). In the extremely
wet conditions of 1990, ’Penncross’ was the best cultivar throughout the season. ’Penneagle’, ’J. H. Bent’,
’Pennlinks’, and ’Putter’ also performed very well (Table 8).

Table 8. The 1990 ratings for the fairway bentgrass study established in the fall of 1988.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

Cultivar

May

June

July

Aug.

Sept

Oct

Mean

PENNCROSS
PENNEAGLE
J. H. BENT
PENNLINKS
PUTTER
SOUTHSHORE
PROVIDENCE (SR 1019)
ISI 123
SR 1020
COBRA
ISI 124
EMERALD
CARMEN
NATIONAL
PROMINENT
EXETER (COLONIAL BENT)

7.0
5.7
6.7
5.7
5.3
5.3
5.3
5.0
4.7
5.7
5.3
6.0
5.3
5.0
5.3
4.3

8.0
6.7
7.3
8.0
7.3
7.7
6.3
5.3
5.3
5.7
6.3
5.0
6.3
5.0
5.3
5.0

8.0
8.0
7.3
7.7
8.0
7.3
7.3
6.3
7.7
6.7
7.0
7.0
6.3
5.3
5.0
5.3

6.7
7.7
7.3
7.3
7.0
7.7
7.3
6.3
7.0
6.0
6.0
6.3
6.7
5.3
5.0
5.0

7.0
7.7
6.7
7.3
7.7
7.0
7.7
7.7
7.3
7.3
7.7
6.3
6.3
6.0
5.0
5.0

6.7
7.7
7.0
6.3
6.7
6.7
5.7
7.7
6.7
6.3
5.7
6.3
5.0
6.0
6.3
5.0

7.2
7.2
7.1
7.1
7.0
6.9
6.6
6.4
6.4
6.3
6.3
6.2
6.0
5.4
5.3
4.9

LSD

1.5

1.2

1.1

1.5

1.1

1.7

0.7

0.05

Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality,
and 1 = poorest quality.

20

Fairway Height Kentucky Bluegrass Trial -19 90
N. E. Christians and R. W. Moore

The Kentucky bluegrass plots in this trial were established in 1979 and the study was maintained at
lawn height for nine seasons. In the fall of 1988, the mowing height was slowly reduced to 1 inch to
test the cultivars under conditions similar to a Kentucky bluegrass fairway.
The study was irrigated as needed and fertilized at a rate of 4 lb N/1000 ft2/yr.
’Touchdown’ performed best in 1990 (Table 9). The old standby of the 1970’s, ’Merion’, also
performed surprisingly well. (’Merion’ is no longer available.) ’Midnight’ did very well, but it should be
noted that this cultivar does not stand up well in dry years (see 1990 report) and develops severe
powdery mildew if there is any shade in the area (the test area is in full sun).
’Majestic’ and ’Adelphi’ were the lowest rated cultivars. They are generally recognized as good
performers at lower mowing heights. The wet season may have resulted in deterioration of quality for
these cultivars.

21

Table 9. Quality ratings for the fairway height Kentucky bluegrass trial.

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.

Cultivar

May

June

July

Aug

Sept

Mean

TOUCHDOWN
MERION
MIDNIGHT
A-20-6
WABASH
GLADE
A-20
ASPEN
(WTN) H-7
AMERICA
FANFARE
(WTN) 1-13
K76-86-4
PARADE
VICTA
VANTAGE
COMMON
K3-160
BFB-35
PLUSH
BRISTOL
SV-01617
ESCORT
CHERI
BARON
PARK
KIMONO
N- 535
FYLKING
BONNIEBLUE
SYDSPORT
COLUMBIA
ENMUNDI
P-164B
A- 34
BARBIE
TRENTON
RUGBY
MERIT
SENIC
RAM I
AQUILLA
SVING
NUGGET
ARISTA
BIRKA
PENNSTAR
MAJESTIC
ADELPHI

6.7
7.7
7.3
5.3
6.3
6.3
7.0
7.0
6.3
5.3
8.0
6.0
6.3
7.0
6.0
6.3
6.0
6.7
5.0
5.7
5.3
6.3
5.3
6.0
6.3
6.7
6.3
5.3
5.7
5.7
6.7
6.0
5.3
5.7
5.0
6.0
5.7
5.3
5.7
6.0
5.3
5.0
4.3
4.7
5.3
5.0
5.7
5.7
4.7

6.7
6.3
7.7
7.7
6.3
6.7
6.7
6.7
6.7
7.3
6.7
7.3
6.7
6.3
6.7
6.3
6.3
6.3
6.7
6.0
6.0
6.3
6.7
6.7
6.3
6.0
5.7
6.7
6.7
6.3
6.0
6.3
6.3
6.7
6.3
6.3
6.7
6.7
6.3
6.3
6.3
5.3
6.0
6.0
5.3
6.0
5.7
5.7
5.7

8.0
7.0
7.3
7.3
7.7
8.0
6.7
7.0
7.3
7.7
7.3
7.0
7.3
6.7
7.3
7.0
7.0
7.3
8.0
7.7
6.3 '
7.3
7.7
7.0
6.7
6.7
7.7
7.0
6.3
7.0
6.7
6.3
7.0
6.3
7.3
7.3
6.3
6.7
6.3
6.3
6.3
6.7
6.7
6.3
6.3
6.3
6.3
6.3
6.0

7.7
7.0
8.0
7.3
7.3
7.7
6.7
6.7
6.7
6.3
6.3
7.3
7.0
7.0
6.3
7.3
6.3
6.3
6.3
6.7
7.7
6.7
6.3
5.7
6.3
6.7
6.3
6.3
7.0
6.0
5.7
6.3
6.7
6.7
6.3
5.7
6.3
6.3
6.7
5.7
6.0
7.0
6.7
6.0
6.0
6.0
6.0
6.0
5.7

7.3
8.0
7.2
7.7
7.7
6.3
7.3
7.0
7.7
7.7
6.0
7.0
7.3
7.0
7.7
7.0
7.7
6.7
7.3
7.7
8.0
6.7
7.3
7.7
7.3
6.3
6.7
7.0
7.0
7.7
7.0
7.0
6.7
6.7
7.0
6.0
6.7
6.7
6.7
6.7
7.0
7.0
6.3
7.0
6.3
6.3
6.0
5.7
6.7

7.3
7.2

1.3

1.4

LSD

0.05

NS

NS

NS

7.1
7.1
7.0
6.9
6.9
6.9
6.9
6.9
6.9
6.9
6.8
6.8
6.8
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.6
6.6
6.5
6.5
6.5
6.5
6.5
6.4
6.4
6.4
6.4
6.4
6.3
6.3
6.3
6.3
6.2
6.2
6.2
6.0
6.0
5.9
5.9
5.9
5.9
5.7

1 .0

Quality based on a scale of 9 to 1: 9 = best quality, 6 = acceptable quality,
and 1 = poorest quality.

22

Preemergence Annual Weed Control Study -1990

N. E. Christians and R. G. Roe

The 1990 preemergence annual weed control study was conducted at the turfgrass research area on
a Nicolett (fine-loamy, mixed-mesic, Aquic Hapludoll) soil with a pH of 6.9 and 2.3% organic matter.
The objective of the project was to evaluate the efficacy of several labeled and experimental
preemergence herbicides applied to a ’Park’ Kentucky bluegrass turf for the control of crabgrass.
Plots measured 5 ft by 5 ft. They were arranged in a randomized, complete-block design with three
replications.
The area was seeded in the third week of April with a combination of large hairy and smooth
crabgrass harvested from the research area. Treatments were applied on April 26. Liquids were
applied with a backpack carbon-dioxide sprayer equipped with 8006 nozzles. Granular materials were
applied with a hand-held shaker. The study was irrigated following seeding and a heavy infestation of
crabgrass developed in the control plots. Heavy rains in May, June, and July kept the area well
watered and no additional irrigation was necessary following germination.
The study was observed weekly for signs of phytotoxicity. No damage was observed on any of the
treated plots at any time during the summer of 1990. This was likely due to the very wet conditions
and the lack of stress in the 2-month period following treatment. Estimates of the percentage
reduction of crabgrass were made on July 10. Counts of crabgrass, spurge, and oxalis on the
individual plots were made on August 10 (Table 10).
Ronstar 2G provided excellent crabgrass control at both the 2 and 4 lb ai/a rates as did Exp 03621B
2G (an experimental formulation of the same active ingredient). Ronstar at 4 lbs ai/a was the only
material to provide 100% crabgrass control season-long during this wet season. Exp 03621C 2G was
slightly less effective than Exp 03621B 2G numerically (the differences are not statistically significant).
Exp 30509B 3EC did not provide satisfactory weed control unless repeat applications at the 3 lb ai/a
level were applied at a 30 day interval.
Bensulide was effective, but Dacthal 6F was not. Team pendimethalin and Barricade were effective
and provided similar results at the rates tested.
Gallery is not considered to be a crabgrass control. Its primary use is as a preemergence broadleaf
control. Note that it was very effective on spurge and oxalis in this test. Dimension was quite effective
at the 0.5 lb ai rate. The two Scotts fertilizer materials with pendimethalin were relatively effective.
Both Spring Valley Team and ISU experimental were relatively ineffective in controlling crabgrass.

23

Table 10. Preemergence annual weed control study. Tested April 26, 1990.
Control

T reatment

7/10

Crabgrass
8/10

o**

Ct

Spurge
8/10
Ct

Oxalis
8/10

Ct

0

750

0

2

0

5

99

96

27

0

3

79

1

4.0

100

100

2

50

1

93

0

Exp 03621B 2G

2.0

97

96

31

0

3

100

0

5

Exp 03621B 2G

4.0

98

98

14

83

0

100

0

6

Exp 03621C 2G

2.0

92

81

142

0

5

43

3

7

Exp 03621C 2G

4.0

99

99

5

100

0

100

0

8

Exp 30509B 3EC

4.0

53

35

485

0

4

100

0

9

Exp 30509B 3EC

6.0

91

82

136

0

7

93

0

Exp 30509B 3EC +
Exp 30509B 3EC

3 + 2 (30 days)

98

90

77

0

2

100

0

Exp 30509B 3EC +
Exp 30509B 3EC

3 + 3 (30 days)

100

98

15

50

1

93

0

7.5

99

98

12

0

7

71

1

10.5

29

52

362

50

1

29

3

1

Control

2

Ronstar 2G

2.0

3

Ronstar 2G

4

10

11

12

Bensulide 4E

13

Dacthal 6F

14

Team

2.0

92

93

52

0

2

86

1

15

Pendimethai in 60DG

1.5

95

90

77

0

6

100

0

16

Barricade WG 65%

0.33

98

89

84

0

7

100

0

17

Barricade WG 65%

0.5

98

96

31

0

3

79

1

18

Barricade WG 65%

0.65

99

98

17

0

2

86

1

19

Barricade WG 65% +
Gallery WG 75%

0.5 + 0.75

100

98

13

83

0

100

0

20

Gallery 75% DF

0.5

33

50

379

100

0

100

0

21

Gallery 75% DF

0.75

68

48

390

100

0

100

0

22

Gallery 75% DF

1.0

93

90

72

100

0

100

0

23

Dimension
(Mon 15151 1EC)

0.38

97

94

49

0

5

100

0

Dimension
(Mon 15151 1EC)

0.50

99

97

23

0

2

79

1

Spring Valley
10% Team

2.0

41

38

467

0

3

86

1

Spring Valley
10% Team

1.5 + 1.5
(10 wk)

8

52

360

0

4

86

1

27

Scotts 22-0-6

1.5

96

90

77

33

1

100

0

28

Scotts 30-3-10

1.5

94

87

100

50

1

86

1

29

ISU Exp

43.56*

22

26

558

77

1

0

6

30

ISU Exp

87.15*

56

40

453

0

2

57

2

45

42

319

NS

63

3

24

25

26

LSD
*
**
Ct

Ib/ai
Acre

0.05

lbs material/Acre.
% of the control.
= plant count/25 ft2 plot on August 10.

24

Postemergence Annua! Grass Control Study -1990
N. E. Christians and R. G. Roe

The objective of this study was to investigate the effectiveness of several postemergence annual grass
herbicides for the control of crabgrass. Data was also collected on the control of broadleaf weeds.
The study was conducted on an area adjacent to the Broadleaf and Postemergence Annual Weed
Control Study. The protocols were very similar for the two test sites. The work was conducted on a
Nicolett (fine-loamy, mixed-mesic, Aquic Hapludoll) soil with a pH of 6.9 and 2.3% organic matter.
Individual plots measured 5 ft by 5 ft. They were arranged in a randomized, complete-block design
with three replications. Due to very wet conditions during the study, no additional irrigation was
necessary. The grass on the area was a common Kentucky bluegrass that had been in place
approximately 20 years.
The study area was seeded in the first week of May, 1990, with a combination of large hairy and
smooth crabgrass harvested at the research area and white clover (
repens). Due to the
moist conditions, very high populations of both species developed by early June. There was also a
native population of dandelion on the test area. Treatments were applied on June 20, 1990, at a time
when the crabgrass plants were beginning to form their first tillers. All treatments were applied with a
backpack carbon-dioxide sprayer equipped with 8006 nozzles. The spray pressure was 20-25 psi.
Treatments were applied with the equivalent of 4 gal water/1000 ft2.
Ratings of phytotoxicity on the Kentucky bluegrass were made on July 13, July 20, and August 1 on a
scale of 9 to 1. 9 = no damage and 1 = dead turf. Ratings of 6 and above were acceptable. Weed
counts were made on August 17, 1990. White clover was rated on a percent cover basis. Table 11
lists the average number of other weeds in a 5 ft by 5 ft plot and the percentage reduction from the
control.
The only material to seriously damage the Kentucky bluegrass turf was HOE 360-05H, an experimental
material from American Hoechst (Table 11). This damage was quite severe, particularly at the 0.9 lb
ai/a treatment level. It persisted throughout July and into early August. (Symptoms developed
approximately two weeks after treatment.)
Crabgrass population was very high on the control plots. The 488 plants per plot represent more than
80% cover. Moisture stress before treatment can often reduce the effectiveness of postemergence
annual grass controls. The plot area was very wet during the weeks before treatment and there was
no moisture stress on the area at any time during June and July. Crabgrass control was very good
for most of the materials studied (Table 11). Acclaim, which has provided somewhat inconsistent
control in the last two years when extremely dry conditions existed at the research area, provided 98%
crabgrass control in this study. BAS 514 (Impact) at rates of 0.75 lb ai/a and above was very effective
on plots treated with single applications and plots that received repeat treatments 30 days after the
initial treatment. This material was also quite effective where repeat applications of levels as low as
0.375 lb ai/a were applied. Scotts S-3061 is a granular fertilizer material that contains BAS 514
(Impact). This granular formulation was very effective as a crabgrass control. The Fermenta 2 + 2
was effective as a broadleaf control, but provided no reduction of crabgrass. MON 15104 (Dimension)
was a very effective postemergence crabgrass control as it has been in studies conducted during the
past few years.
BAS 514 (Impact) provided excellent broadleaf control in this study. The improved dandelion control
compared to the adjacent study (Broadleaf and Postemergence Annual Weed Control Study) appears
to be due to the repeat treatments in this study.

25

26

Table 11. Postemergence annual weed control study. Treated June 20, 1990.

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27

Broadleaf and Postemergence Annual Weed Control Study -1 9 9 0
N. E. Christians and R. G. Roe

The objective of this study was to investigate the efficacy of BAS 514 (Impact), an experimental
herbicide currently being evaluated as a postemergence control of annual grasses and broadleaf
weeds in turf areas. The material was applied alone and in tank-mix combinations with other
herbicides (Table 12). The work was conducted on a Nicolett (fine-loamy, mixed-mesic, Aquic
Hapludoll) soil with a pH of 6.9 and 2.3% organic matter. Individual plots measured 5 ft by 5 ft. They
were arranged in a randomized, complete-block design with three replications. Due to very wet
conditions during the study, no additional irrigation was necessary. The grass on the area was a
common Kentucky bluegrass that had been in place approximately 20 years.
The study area was seeded with a combination of large hairy and smooth crabgrass harvested at the
research area and white clover (Trifolium repens) in the first week of May 1990. Due to the moist
conditions, very high populations of both species developed by early June. There was also a native
population of dandelion on the test area. Treatments were applied on June 20, 1990, at a time when
the crabgrass plants were beginning to form their first tillers. All treatments were applied with a
backpack carbon dioxide sprayer equipped with 8006 nozzles. The spray pressure was 20-25 psi.
Treatments were applied with the equivalent of 4 gal water/1000 ft2.
Ratings of phytotoxicity on the Kentucky bluegrass were made on July 13, July 20, and August 1 on a
scale of 9 to 1. 9 = no damage and 1 = dead turf. Ratings of 6 and above were acceptable. Weed
counts were made on August 17, 1990. White clover was rated on a percent cover basis. Table 12
lists the average number of other weeds in a 5 ft by 5 ft plot and the percentage reduction from the
control.
No damage occurred on the Kentucky bluegrass in any of the treated plots (Table 12). BAS 514
reduced crabgrass infestation at the 0.25 and 0.375 lb ai/a rates, but did not provide satisfactory
control below rates of 0.5 and 0.75 lb ai. Tank-mix combinations with 2,4-D, 2,4DP-P, MCPP-P, and
Trimec appeared to reduce crabgrass control to some degree, although the reductions were not
statistically significant. Dimension and Confront slightly increased crabgrass control, although again
the increase was only numerical and does not exceed the LSD value.
Clover control was excellent for all rates of BAS 514 at 0.5 lb ai/a and above and was not reduced
significantly by any of the tank-mixes. Dandelion control was not satisfactory in any of the plots
treated with BAS 514 alone and was less than would be desired with many of the tank-mix
combinations. Trimec was required in this test for satisfactory dandelion control.
Spurge (Euphorbia supina) and oxalis (Oxalis stricta) germinated after treatment and there were no
statistical differences among treatments.

28

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On a scale of 9 to 1. 9 = no damage and 1 = dead turf.
PI # = Plant count/25 sq ft plot.
% Ct = Percent of the control.
% Cvr = Percent cover.
Pt
= Pints of product/Acre.

Table 12 Broadleaf and postemerqence annual weed control study. Treated June 20, 1990.

0

10
(0 p

Broadleaf W eed Control Study - 1 9 9 0
R. G. Roe and N. E. Christians

The objective of this study was to investigate the efficacy of ten herbicides currently being evaluated
as postemergence controls of broadleaf weeds in turf areas. The study was conducted on a site in
southeast Ames at the intersection of Highway 30 and Interstate 35. Individual plots measured 5 ft by
10 ft. They were arranged in a randomized, complete-block design with three replications. No
irrigation was available at the site. However, due to very wet conditions throughout the duration of the
study no drought stress was present. The grass on the area was a common Kentucky bluegrass of
unknown age.

This site had a good population of the following broadleaf weeds: dandelion (
officianale),
white clover (
Trifoliumrepens), and spurge (
Euphorbiasupina). Treatmen
1990. All treatments were applied with a backpack carbon dioxide sprayer equipped with 8006
nozzles. The spray pressure was 20-25 psi. Treatments were applied with the equivalent of 3 gal
water/1000 ft2. A light rain occurred four hours after treatment.
No phytotoxicity was observed on the Kentucky bluegrass. Weed counts were made at 30 days.
Table 13 lists the average number of weeds in a 5 ft by 10 ft plot. Turflon D and Super Trimec were
the only products to provide satisfactory control of dandelions, clover, and spurge. Confront at the
2 pt ai/a rate showed a numerical reduction of dandelion.
Both Turflon D and Super Trimec were ester formulations that would be expected to penetrate the leaf
surface quickly and provide better control in the very wet conditions present during the study period.
The amine formulations, while not performing in this test, provide a greater degree of safety for
surrounding landscape plants.

30

Table 13. Broadleaf weed control. Treated August 2, 1990.

Treatment

lb ai/
acre

Dandelion

Clover

Spurge

428

17

5

1

Control

2

RD 392020

1.8 lb

425

2

31

3

RD 392020

2.5 lb

346

13

7

4

RD 104100

2.5 pt

310

11

15

5

RD 104100

3.5 pt

223

2

8

6

Triamine

3.0 pt

247

8

11

7

Triamine

4.0 pt

306

3

4

8

XRM 5202

2.0 pt

343

27

13

9

XRM 5202

3.0 pt

230

16

15

10

XRM 5202

4.0 pt

323

4

20

11

Turflon II Amine

3.0 pt

253

23

11

12

Turflon D

3.0 pt

16

0

2

13

Confront

1.0 pt

210

0

25

14

Confront

1.5 pt

256

0

21

15

Confront

2.0 pt

171

0

19

16

Trimec

4.0 pt

310

2

43

17

Super Trimec

2.5 pt

46

0

1

18

XRM 5290

1.38 lb

383

2

15

174

NS

NS

LSD
Plots measure 5 ft by 10 ft.
Treated August 2, 1990.

31

Effects of Dithiopyr (Dimension) on the
Rooting of Creeping Bentgrass
N. E. Christians and R. G. Roe

Dithiopyr (Dimension) is a new herbicide likely to be labeled for use on Kentucky bluegrass and other
turf species in 1991. It functions both as a preemergence and early postemergence control of
crabgrass. Trials with this compound on creeping bentgrass have been limited and little is known
about the response of bentgrass to this compound at green-mowing height.
The objectives of this study were to observe rooting responses and foliar phytotoxicity to dithiopyr on
creeping bentgrass mowed at 3/16-in and maintained under putting green conditions.
The turf was a 10-year-old stand of ’Penncross’ creeping bentgrass established on a 1:1:1
(sand:soil:peat) soil mixture with a pH of 7.1. (Three plots of each replication extended into an
adjacent area of ’Penneagle’ creeping bentgrass. Observations during the study indicated no
variation in response and these plots were included in the analysis.)
The area received 3-4 lb N/1000 ft2 in 0.2 lb increments as needed. No P or K was applied. Standard
fungicide and insecticide treatments were made uniformly on all plots. Each plot measured 5 ft by 5 ft
and the study was replicated three times. Treatments were applied on May 9, 1990, with a carbondioxide backpack sprayer (Table 14).
The plots were observed for signs of visible treatment differences throughout the summer. At no time
were there any signs of phytotoxicity. There was an initial positive response to the granular
formulations of dithiopyr in some replications. This appeared to be due to a nutritional stimulation of
the grass by the carrier. These responses were not consistent enough to be significant.
Root samples were collected on June 9 and August 5 to a depth of 20 cm. The diameter of the cores
was 2.54 cm and six cores were collected per plot. The samples were divided into four subsamples:
0-5, 5-10, 10-15 and 15-20 cm. All soil was washed from the root samples. Samples were dried,
weighed, and ashed at 500°C. Root weights were reported as the difference between ashed and dry
weights.
Rooting varied by depth on June 9, but was not affected by herbicide treatment. Rooting on August 5
varied with depth, and all herbicide-treated bentgrass showed significantly reduced root weight from
the control. There were no differences in rooting among herbicide treatments.
Bensulide is a labeled compound for use on bentgrass greens and was used as a standard in this
trial. Root weights of dithiopyr treated bentgrass were generally equal to or greater than that of
Bensulide-treated plots. This information combined with the lack of visible phytotoxicity would indicate
that dithiopyr is probably as safe as Bensulide for use on these varieties of creeping bentgrass
maintained at green height.

32

Table 14. Response of creeping bentgrass to dithiopyr and other preemergence herbicides.

CM
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1990 Sod Rooting Trial

R. G. Roe and N. E. Christians

The purpose of this study was to observe the effects of selected pesticides on establishment and
rooting of sod. The test was conducted on a Nicollet (fine-loamy, mixed mesic, Aquic Hapludall) soil
with a pH of 6.9 and 2.3% organic matter. Individual treatment cells measured 5 ft by 5 ft and were
randomized in a complete block design with three replications. Water was applied as needed.

Treatments are listed in Table I5.
Table 15. Treatments included in the 1990 rooting trial.

Treatment

lb ai/a

Product/
5 x 5 ft plot

h 2o /

plot

1.

Control

2.

Banner 1.1E

2.0 oz/1000ft2

1.47 ml

380 ml

3.

Banner 1.1E [repeat 2 wk]*

2.0 oz/1000 ft2

1.47 ml + 1.47
ml*

380 ml

4.

Super Trimec

3.0 pt / Acre

0.82 ml

380 ml

5.

Turflon D

3.0 pt / Acre

0.82 ml

380 ml

6.

Turflon II Amine

3.0 pt / Acre

0.82 ml

380 ml

7.

Confront

1.0 pt / Acre

0.27 ml

380 ml

8.

Confront

1.5 pt / Acre

0.40 ml

380 ml

9.

Confront

2.0 pt / Acre

0.54 ml

380 ml

10.

Dursban 4E

1.0 lb ai / Acre

0.54 ml

380 ml

11.

Triumph 4E

1.0 lb ai / Acre

0.54 ml

380 ml

* Repeat in 14 days.

—

—

—

Treatments were applied to the sod on September 19, 1990, with a backpack carbon-dioxide
sprayer for the liquid materials, and a shaker box for the granular materials (Table 15). The
Kentucky bluegrass turf was cut at a 3/4-in depth and laid in the standard fashion. Sod
pieces were transplanted into wooden frames, 3 frames per plot. The frames had 18-mesh
fiberglass screen bottoms and were constructed of 1 x 2 in pine boards with inside
dimensions of 12 x 12 in. Screw hooks were placed at each of the four corners for use as
the point of attachment for the hydraulic lift apparatus.
Rooting was measured with a technique modified from King (King & Beard, 1969). The
frames were lifted vertically with a hydraulic pump apparatus. Woven steel cords were
attached to each of the four-hook screws on the frame and drawn to an apex over the center
of the frame. The lifting apparatus was raised by mounting it on a wooden crate 1 ft above
the level of the turf, centered carefully over the frame to assure that the lifting force was
vertical. The force at the point of root breakage from the soil was measured by use of a
hydraulic pressure gauge. Rooting measurements were used as an indication of sod
establishment. The frames were lifted 20 and 30 days following treatment. Visual quality
ratings were recorded at 20 and 30 days. Quality was rated on a scale of 1 to 9, 9 = best, 5
= acceptable, and 1 = dead turf. An analysis of variance was performed on all data.
There were no significant differences in sod pulling pressure at either the 20 or 30 day testing
time (Table 16). By the 20th day following treatment, the fungicide Banner 1.1E at the 2
oz/1000 ft2 single application rate showed the greatest numerical pulling pressure. All other
treatments reduced root development at 20 days compared to Banner 1.1E. Super Trimec at
3 pt/a and Banner 1.1E at the 2 oz/1000 ft2 with a repeat application at two weeks showed
the greatest reduction.
By the 30th day, the grass on plots treated with Banner 1.1E at the 2 oz/1000 ft2 with a
repeat treatment and Dursban 4E at 1 lb ai/a had numerically greater pulling pressure than
the other treatments. Turflon D and Turflon II Amine showed the greatest reduction in rooting.
No noticeable differences in turf quality were visible after treatment.
King, J. W. and J. B. Beard. 1969. Measuring rooting of sodded turf. Agronomy Journal
61:497-498.

35

Table 16. Pulling pressures measured on treated sod at 20 and 30 days after treatment.
Pulling Pressure PSI
Treatment
1.

Control

2.

Banner 1.1 E

3.

Rate

20 days
Wood

30 days
Wood

143.3

230.0

2.0 oz/1000 ft2

203.3

231.6

Banner 1.1E repeat 2 wk*

2.0 oz/1000 ft2

156.6

346.6

4.

Super Trimec

3.0 pt/Acre

147.5

271.6

5.

Turflon D

3.0 pt/Acre

180.0

160.0

6.

Turflon II Amine

3.0 pt/Acre

166.6

203.3

7.

Confront

1.0 pt/Acre

176.6

210.0

8.

Confront

1.5 pt/Acre

171.6

306.6

9.

Confront

2.0 pt/Acre

182.5

240.0

10.

Dursban 4E

1.0 lb ai/Acre

193.3

316.6

11.

Triumph 4E

1.0 lb ai/Acre

200.00

256.6

—

* Repeat In 14 days.

36

The Effect of Prograss on the Establishment
of Cool-Season Grasses
N. E. Christians

Prograss (ethofumesate) is marketed as a postemergence control of annual bluegrass Poa annua
established in perennial ryegrass, creeping bentgrass (fairway height only), and Kentucky bluegrass turf
on golf courses. The objective of this study was to observe the effects of prograss on establishment of
five cool season-grasses from seed.
Prograss was applied to freshly tilled soil on Aug 30,1990, to 10 ft by 5 ft plots at rates of 0 (control), 0.5,
and 0.75 lbs. ai/a. Shortly after treatment the plots were split into 5, 2 ft by 5 ft sub-plots and seeded with
the following grasses:
Grass

1.
2.
3.
4.

Rate
(lbs/1000lt?)

’Ram T Kentucky bluegrass
’Manhattan II’ Perennial Ryegrass
’Arid’ Tall Fescue
’Penncross’ Creeping Bentgrass

1.5
6.0
8.0
1.0

A fifth grass, ’Reliant’ hard fescue, was seeded 30 days later on Sept 30 at a rate of 3 lbs/1000 ft.2.
Follow-up treatments of Prograss were made on Sept 30 and Oct 30 at the same rates applied on the Aug
30 treatment date.
Observations of percent cover were made at 14 days, 60 days, 75 days (end of the season), and in the
spring of 1991 (Table 17). Perennial ryegrass and tall fescue were unaffected by Prograss at either rate.
Kentucky bluegrass stand was reduced by two thirds by Prograss at the 0.5 lb ai/a rate and by 98% at
the 0.75 lb ai/a rate. ’Penncross’ creeping bentgrass was reduced by 52% at the 0.5 lb ai rate and by
87% at the 0.75 lb ai rate. ’Reliant’ hard fescue was severely reduced at both rates of prograss.
In an earlier study (1990 Iowa Turfgrass Research Report, p 57-60) ’Shade Master’ creeping red fescue
showed greater tolerance to Prograss than did the closely related ’Reliant’ hard fescue in this study. The
earlier study involved delayed seeding dates. More work will be required to determine if these differences
in response of the fine fescues are due to seeding date or variety/species differences.

37

Table 17. The percent cover of 5 cool-season grasses treated with prograss

14 days

60 days
% cover

75 days

Spring

Control
Kentucky Bluegrass
Perennial Ryegrass
Hard Fescue*
Tall Fescue
Creeping Bentgrass
Prograss 0.5 lbs ai
Kentucky Bluegrass
Perennial Ryegrass
Hard Fescue
Tall Fescue
Creeping Bentgrass
Prograss 0.75 lbs ai
Kentucky Bluegrass
Perennial Ryegrass
Hard Fescue
Tall Fescue
Creeping Bentgrass

38
73
-

60
68

8
76
—

53
15

3
70
—

52
7

87
100
47
100
100

70
100
30
100
100

92
100
47
100
100

33
100
8
100
37

27
100
4
100
25

32
100
3
100
48

6
100
6
100
13

3
100
3
97
12

*Hard fescue was not seeded until 30 days after the other 4 grasses.

38

2
100
0
100
13

Poa annua Control with Ethofumesate
on Veenker Golf Course
N. E. Christians, B. Peterson and J. Newton

A demonstration on the use of Ethofumesate (prograss) was established at Veenker Memorial Golf Course
in Ames in the fall of 1990. The objective was to evaluate the effectiveness of this material for the control
of Poaannua on greens, tees, and fairways.
On September 14,1990, we applied the first application of Ethofumesate to the No. 14 fairway and green
and to the No. 15 women’s tee. On the fairway and tee, we used a rate of 0 (control), 0.50, and 0.75
pounds active ingredient per acre. Each test strip was 15 ft wide. The length of the fairway strips was
approximately 50 yds. The strips on greens and tees were the length of those areas, respectively. Two
additional applications were made to the same areas on October 22 and November 16.
Loss of Poa annua was observed on the fairway and tee in the spring of 1991. The Poa annua on the
green, however, was killed at all rates of Ethofumesate and remained healthy in the control strip. By late
May, the percentage of bentgrass had increased greatly in the treated plots on the green, whereas the
Poa annua was the predominate species in the control strip. No damage was observed on the bentgrass
at any time during the fall or spring.
The lack of Poa annua control on the fairway and tee is still a mystery. The areas were treated at the
same time with the same sprayer, yet only the Poa annua on the greens was killed. The differences may
be due to variations in biotype of the Poa on the areas, or there may have been some unobserved
differences in environmental conditions among the areas. More work is planned for this fall to determine
the reasons for the differences in control observed in the spring of 1991.

39

Fairway Height Bentgrass Response to Fenoxaprop
N. E. Christians and R. W. Moore

Fenoxaprop (Acclaim) is a postemergence herbicide used for the control of crabgrass in Kentucky
bluegrass lawns and other turf areas. Its use on bentgrass is currently not recommended because of
concerns over phytotoxicity. Bentgrass cultivars are known to vary in response to herbicides and if
there are bentgrasses that can tolerate fenoxaprop, this information would be of use to golf course
superintendents.
The objective of this study was to observe the response of 15 creeping bentgrass cultivars and one
colonial bentgrass cultivar maintained at fairway height (0.5 in) to fenoxaprop at 0.032 and 0.064 lb
ai/a.
The two-year-old stand of creeping bentgrass is located at the Iowa State University Horticulture
Research Station on Section 4 of the turfgrass research area. The soil is a Nicolett (fine-loamy, mixedmesic, Aquic Hapludoll) with a pH of 6.8, 2.3% organic matter and 208 lb K/a. The area received 3 lb
N/1000 ft2 in 1990 in the form of urea. It was mowed at 0.5 in twice weekly during the season. The
bentgrass variety trial on which this study was conducted was replicated four times. The fenoxaprop
treatments were stripped across the replications. Treatment strips were randomized within
replications.
Fenoxaprop treatments were made during the late afternoon of June 20, 1990. The area was not
watered for 24 hours following treatment. On June 22, 1 in of rain was recorded. Another 1.5 in fell
on June 24, and 1 in was recorded on June 28. The area was not under moisture stress during the
study.
The first signs of phytotoxicity were observed on June 25, five days after treatment (Tables 18 & 19).
’Southshore’, ’Penncross’, and ’SR 1020’ were the most tolerant cultivars and were not rated as
unsatisfactory at any time following treatment at the 0.064 lb ai/a rate of fenoxaprop. 'Cobra', 'ISI 123’,
’Emerald’, ’Prominent’, ’Carmen’, and ’National’ were most damaged by the fenoxaprop treatment.
Nearly all of the damaged turf had recovered by July 9.
The results of this study indicate that bentgrass cultivar can play an important role in how fairway
height bentgrass will respond to fenoxaprop treatments. ’Penncross’, ’Penneagle’, and ’Pennlinks’, all
cultivars that are commonly used in the midwest, showed only minor damage at the 0.032 lb ai/a level
of fenoxaprop. Penncross appeared to be the best cultivar at the 0.064 lb ai/a rate.

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The Response of Kentucky Bluegrass Turf to Mefluidide
Applied in Combination with Fungicides and Other Com pounds
N. E. Christians and S. Luke

Mefluidide (Embark) is a growth-regulating compound labeled for use on Kentucky bluegrass turf.
Under some conditions, its use can result in turf discoloration. In this study, two fungicides
propicanazole (Banner) and triadimefon (Bayleton), Ferromec (an iron source), and BA
(benzyladenine, a synthetic cytokinin plant hormone) were applied in combination with mefluidide.
The objectives of the study were to determine if the additives would reduce turf discoloration and to
observe any effects the chemicals may have had on turf growth response to mefluidide.
The study was conducted on a 5-year-old mixed stand of ’Parade’, ’Glade’, ’Rugby’, and ’Adelphi’
Kentucky bluegrass established on a Nicolett (fine-loamy, mixed-mesic, Aquic Hapludoll) soil with a pH
of 6.9 and 2.3% organic matter. The turf was mowed at 2 in and had received 1 lb N/1000 ft2 before
treatment. Treatments were applied on May 2 in three replications to 5 ft by 5 ft plots (Table 20).
All of the treated plots were observed to have significantly lower turf quality than the control on May
16, June 1, and June 8 (Table 20). Ferromec AC provided an initial response over mefluidide alone at
the first rating date, but no significant effects were observed after that time (Table 20). No significant
response was observed on plots treated with propicanazole. BA and triadimefon did not significantly
alter turf quality on any of the treated areas beyond those effects observed with mefluidide alone.
All treated plots had significantly reduced leaf height from the control and all displayed greatly
reduced seedhead formation.
At the highest rate, propicanazole and triadimefon appeared to improve growth suppression over plots
treated with mefluidide alone, although these variations were not significantly different at the 0.05 level.
There were no differences in seedhead suppression among any of the treated plots.
The spring and summer of 1990 were extremely wet. Through much of the test period, the plot area
was saturated. In spite of the excessive moisture, mefluidide was effective in suppressing growth and
seedhead formation. The effects of the additives may have been affected by the moisture, however,
and further work should be conducted with these materials under more normal conditions.

43

0

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Evaluation of Fungicides for Control of Leaf Spot on
Park Kentucky Bluegrass -1990
M. L. Gleason

Trials were conducted on the Turfgrass Research Plots at the Horticulture Research Station of Iowa State
University near Ames, Iowa. Fungicides were applied to Kentucky bluegrass (cultivar: ’Park’), maintained
at a 2 1/2 in cutting height, with a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal/1000 ft2.
The experimental design was a randomized complete-block plan with four replications. All plots measured
4 ft by 5 ft. Fungicides were applied on a 14, 21, or 28 day schedule (Table 22). Applications began on
June 5 and continued through July 16. Plots were evaluated for severity of leaf spot symptoms on July
11 and August 10.
Leaf spot was present at trace to low levels on all rating dates. ASC-66608 at 5 oz (July 11), ASC-66518
at 3.8 oz (July 31), and ASC-66608 at 7.5 oz (July 31) had leaf spot levels significantly below the check.
No phytotoxicity symptoms were noted on any rating date.

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Evaluation of fungicides for control of leaf spot in Park

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Evaluation of Fungicides for Control of Snow Molds on
Creeping Bentgrass, 1990-1991
M. L. Gleason

The trial was conducted on a creeping bentgrass green (Hole #4) at the Waverly Municipal Golf Course,
Waverly, Iowa. This green had a history of outbreaks of gray and pink snow molds in most of the last 10
years. The experimental design was a randomized, complete-block with 4 replications. All plots measured
5 ft by 5 ft Fungicides were applied on November 13, 1990, using a modified bicycle sprayer at 30 psi
and a dilution rate of 5 gal/1000 ft2.
Immediately after application of fungicides, the entire plot was covered with two layers of Curlex HighVelocity excelsior mats (American Excelsior Co., St. Paul, MN). The mats were fixed in place with wire
stakes. The purpose of the mats was to simulate snow cover and provide favorable conditions for the
development of snow mold even in the absence of snow cover (W. Stienstra, Department of Plant
Pathology, University of Minnesota, personal communication).
Snow cover persisted on the green from December 5, 1990, until March 1,1991. Mats were removed on
March 6. On that date, symptoms of gray and pink snow mold were abundant at many sites on the golf
course.
Snow-mold development on untreated check plots was moderate (Table 23). Symptoms of both gray and
pink snow mold were evident in these plots. All fungicide treatments were free of snow mold damage.
None of the fungicide treatments were significantly different from the others in disease suppression.
Treatments that incorporated green paint were perceptibly greener in color than other treatments. No
phytotoxicity symptoms were observed.
Because snow-mold occurred naturally at Waverly Municipal Golf Course in 1990-91, no conclusion could
be drawn about the effect of excelsior mats on disease development. However, in winters with less than
3 months of snow cover (a common occurrence in Iowa), the mats may provide temperature and moisture
conditions favorable for snow mold development.

Table 23. Evaluation of fungicides for control of snow mold in creeping bentgrass at Waverly Municipal
Golf Course, Waverly, IA, 1990-91.

Company
-----Check
ISK Biotech
ISK Biotech
ISK Biotech
ISK Biotech
DowElanco
Nor-AM
Terra
Terra
Terra
Grace-Sierra
0. M. Scott

Rate/1000 ft2
with symptoms8

Treatment

17.5 a
16 oz
16 oz
1 gal/40 gal H20
8 oz
8 oz
1 gal/40 gal H20
8 oz
1.25 oz ai

Daconil 2787
Daconil 2787
+ green latex paint(67019)
ASC 66791
ASC 66791
+ green latex paint(67019)
Rubigan 1AS
NA249 70 WDG
(coformulation)
Banner 1.1 EC
Banner 1.1 EC
+ Plex
Rubigan 1AS
+ Plex
Calo-Gran
S-2621

a Means of 4 replications.
P=0.05).

4 oz
0.25%
8 oz
0.25%
8 lb
2.6 kg

0b
0b
0b
0b
0.5 b
0b
0b
0b
0.5 b
0b
0b

Means followed by the same letter are not significantly different (DMRT,

48
%

Percentage of Plot

Evaluation of Fungicides for Control of Dollar Spot on
Emerald Bentgrass -1990
M. L. Gleason

Trials were conducted on the Turfgrass Research Plots at the Horticulture Research Station of Iowa State
University near Ames, Iowa. Fungicides were applied to ’Emerald’ bentgrass maintained at a 5/32-in
cutting height with a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal/1000 ft2. The
experimental design was a randomized complete-block with three replications. Treated plots were
alternated with untreated plots so treated plots did not adjoin each other. All plots measured 4 ft by 5
ft. Fungicides were applied on a 14, 21, or 28-day schedule (Table 24). Applications began on June 5
and continued through July 17. Plots were evaluated for severity of leaf spot symptoms on June 28, July
11, July 27, and August 10.
The entire plot was inoculated with rye grains infested with the dollar spot pathogen on May 31, 5 days
before fungicide applications were begun.
As noted in Table 24, the August 10 rating was taken approximately 3 weeks after the final spraying. On
this date, the rating was intended to be a measure of residual activity for 14-day-interval treatments,
because ratings were made 3 rather than 2 weeks after spraying.
Disease ratings for dollar spot were made by counting the number of dollar spot infection centers per plot.
Disease began to appear on June 21. Disease pressure was moderate to severe on June 28 and July
11 and very severe on July 27 and August 10.
Almost all treatments suppressed dollar spot significantly better than the check (unsprayed) treatment.
The only exceptions were Banner at 1 oz, Banner at 0.5 oz plus Plex at 0.37 oz, and Chipco 26019 Flo
at 4 oz on June 28. All the curative treatments had significantly fewer dollar spot infection centers per
plot than the check on July 13 and July 26. No phytotoxicity symptoms were noted on any rating dates.

49

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10 ratings were made 3 weeks after final sprays were applied,
followed by the same letter are not significantly different (DMRT, P - 0.05).

24. Evaluation of fungicides for control of dollar spot in Emerald bentgrass

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Report of Insecticide Evaluation

D. R. Lewis, N. E. Christians

Damage to turfgrass by annual white grubs (Cyclocephala spp.) is a common, but spotty and locally
severe problem in Iowa. Amount of damage varies greatly from place to place and year to year,
depending on several factors such as grass variety, cultural maintenance practices, irrigation, and
weather. Root feeding by these masked chafer larvae characteristically causes grass to wilt, turn tan, and
finally die, usually in late August or early September. Several granular and sprayable insecticide products
are registered for white grub control. Timing of insecticide application is very important in achieving
effective control of white grubs before damage becomes severe.
The objective of this study was to evaluate and compare the efficacy of several registered and
experimental insecticides against annual white grubs infesting turfgrass.
The study was conducted on a rough area of the Hyperion Field Club located in Johnston, Iowa (Polk
County). The soil at the club is a Waukegan loam (fine silt over sandy, mixed, mesic typic Hapludoll) with
148 Ib/a P, 480 Ib/a K, and 5% organic matter. The plots were on an east-facing slope. The grass
species in the plots were Kentucky bluegrass and a small amount of crabgrass. The rough was receiving
low maintenance but regular mowing (at approximately 3 in) and irrigation as necessary. There was
between 1/4 and 1/2 in of thatch at the test site.
Grubs were present in the plot area at the time of insecticide application. Grass was very healthy and
lush as a result of unprecedented rainfall during the first 8 months of 1990. The insecticide treatments
were applied on August 16, 1990 except for the low rate of Gamma-Mean 400 (0.7 lb ai/a) which was
applied on August 21, 1990. Grub population counts were made September 27, 1990.
The experimental design consisted of 12 treatment plots and one untreated check plot, randomly
assigned in each of three replications. Each plot consisted of a 5 ft2 area (25 ft2). All insecticides were
applied at the rate specified on the manufacturer’s label or product guidelines. Liquid and dry flowable
insecticides were diluted with water. The Gamma-Mean 400 product was tank-mixed with a penetrant
supplied by the manufacturer. Sprays were applied with a compressed gas, backpack sprayer connected
to a hand-held, three-nozzle boom. The boom covered a 5 ft wide area, and diluted insecticide spray was
applied to the test plots with alternating perpendicular passes over the treatment area. The amount of
spray solution applied to each plot was the equivalent of 131 gal or 3 gal per 1000 ft2. Granular
insecticides were premeasured into round, cardboard containers and applied uniformly over the plot by
shaking through a perforated lid. The insecticides were watered into the turfgrass with approximately 1/2
in of irrigation.
Annual white grub population counts were made five weeks after treatment by randomly selecting four
sample sites within each plot and cutting an 8 in circular plug with a "large cup" cutter. The sod was
removed from the cut area and the root mass carefully parted and examined for living grubs. The soil
beneath the cut sod was scratched loose to a depth of 2 in and similarly examined. The total number
of white grubs found in each sample was recorded. Population counts in the samples were converted
to number of white grubs per square foot for analysis and reporting.

51

The insecticides used in this project, formulation, rate of application, and mean number of white grubs
per square foot are given in Table 25. Significant differences among treatments and between treatments
and the untreated check were difficult to determine because of very low numbers of white grubs in the
untreated checks and variation in population density among replications. However, a nonrestricted least
significant difference (LSD) test was done to examine for significant differences in the treatment plots.
The average population density in the untreated check plots was only 1.9 white grubs per square foot.
This is less than the population density threshold considered sufficient to cause damage in irrigated,
healthy turfgrass. Indeed, the grass in the plots looked very good at the time of grub counting and root
damage was very slight as evidenced by the strong root system connecting the cut plugs to the soil.
In spite of the low white grub numbers, differences in product performance can be detected. The high
rate of Triumph 4E, Chipco Mocap 5G, and the Oftanol 2E provided significant control. Population
reduction just outside the significant range was achieved with Triumph 1G (both rates) and Pageant DF
chlorpyrifos. The chlorpyrifos observation is interesting in light of poor performance of Dursban products
in earlier trials at this golf course and frequent complaints about Dursban performance within the turfgrass
industry.
Products providing little or no control of white grubs included the low rate of Triumph 4E, Chipco Sevimol
4E, Gamma-Mean 400 (both rates), and Dylox SP.

52

Table 25. Effects of commercially available insecticides on annual white grubs infesting turfgrass, Polk
County, Iowa, 1990.

Insecticide /
Formulation

Control
Triumph 4E
Triumph 4E
Triumph 1G
Triumph 1G
Chipco Sevimol 4E
Chipco Mocap 5G
Gamma-Mean 400
Gamma-Mean 400
Oftanol 2E
Dylox 80 SP
Turcam 2.5G
Pageant DF (chlorpyrifos)

Rate
lb ai/A

1.0
2.0
1.0
2.0
8.0
5.0
0.7
1.0
2.0
8.2
2.0
1.0

LSD (p>F = 0.14)

Population count date - September 27, 1990

Mean number white grubs
per square foot

1.9
0.7
0.0
0.3
0.3
1.0
0.0
1.6
1.2
0.0
1.2
0.0
0.3
1.7

+

Controlling Adult Bluegrass Billbugs
in Kentucky Bluegrass - 1990
S. M. Kassmeyer, D. R. Lewis, M. L. Agnew, and N. E. Christians

Damage resulting from the bluegrass billbug Sphenoohorus parvulus Gyll. is generally not observed
until late summer when it is too late to chemically treat the billbugs. A more effective means of
controlling the bluegrass billbug is to kill the adult billbug before egg laying in April or early May.
The objective of this field test was to study the effectiveness of 12 insecticide treatments in controlling
adult bluegrass billbugs in the spring as they emerge.
This study was conducted on a home lawn in Fort Dodge, Iowa, with the help of Myron Groat, owner
ABC Lawn Care. The testing area consisted of Kentucky bluegrass,
oratensis L. and red fescue,
Festuca
L. An apparent thatch layer was present. The area consisted of 12 insecticide
a
b
ru
treatment plots and one untreated check plot, randomly assigned, and replicated three times (Table
26). Each plot consisted of a 5 ft by 5 ft2 area. The testing area was partially shaded during late
afternoon. The plot area was mowed at 2 1/2 inc and received record rainfalls in May, June, and July.
Larvae damage from the previous year was apparent and adult bluegrass billbugs were found before
treatments were applied. The insecticide treatments were applied on April 20, 199,0 with a carbondioxide backpack sprayer attached to a Chemlawn gun.
The plots were evaluated for billbug damage on July 7, 1990 (Table 26.). Very few larvae were
observed in the test area. Each plot was rated on a scale of 0 to 10, with 0 equalling no injury and 10
equalling 100% injury. Very little visual damage was observed in the test area. No significant
differences were observed in the July 7th rating.
The lack of billbug activity on this particular site was unexpected. This lawn had billbug damage the
previous three years. The only difference was that climatic conditions of 1987 through 1989 were dry.
In 1988, which was the hottest and driest on record, billbug damage to this lawn was extensive. In
1990, the rainfall in Fort Dodge hit an all-time high. Over 35 in of rainfall were registered by August 1.
The excessive rains either masked billbug injury or prevented a viable hatching in 1990.

54

Table 26. Effects of different insecticide formulations on adult bluegrass billbugs infesting turfgrass,
Fort Dodge, Iowa.

Treatment
Number

Insecticide
Formulation

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.

Dursban Turf Insecticide
Dursban Turf Insecticide
XRM-5184
XRM-5184
Empire *20
Empire *20
Pageant DF
Pageant DF
Triumph 4E
Turcam
Tempo
Gamma-Mean 400
plus Penetrator

13.

Control

Rate
MAI
1 Ib
0.5 Ib
1 Ib
0.5 Ib
1 Ib
0.5 Ib
1 Ib
0.5 Ib
2 Ib
(1 oz/1000 ft2)
(6 oz/1000 ft2)
(.8OZ/1000 ft2)

Damage
Rating
2.0
1.0
1.3
1.3
2.0
2.0
2.7
1.0
1.3
1.7
1.0
0.7

1.7

All treatments were applied with 380 ml H20/plot, equivalent to 4 gal/1000 ft2.

55

CORON Research at Iowa State University

M. L Agnew and S. M. Kassmeyer

CORON Bum Study: A foliar burn study was designed to compare the effects of two fertilizer sources,
two nitrogen rates, and three water dilution rates on the burn potential of Kentucky bluegrass,
pratensis L. The two fertilizer sources were CORON (28-0-0) and urea (46-0-0). The intended nitrogen
rates were 1 and 2 lb N/1000 ft2 for both N sources. However, due to a calculation error, the nitrogen
rate for CORON on the first treatment date was 2 and 4 lb N/1000 ft2. Each fertilizer source and
nitrogen rate was diluted into 1-, 3-, and 5-gal of water/1000 ft2. A list of treatments is included on
Tables 27, 28 and 29. Each plot measured 5 ft by 5 ft and was replicated 3 times in a randomized,
complete-block design. Irrigation was provided to the plots to prevent drought stress. All plots were
maintained at a cutting height of 2 in prior to treatments. Plots were left unmowed for 2 weeks
following the initial treatment. Treatments were applied on the following cultivars of Kentucky
bluegrass:
June 28
July 16
September 5

’Glade’
’Park’
’Glade’

Burn ratings and recovery quality data were recorded after each treatment. Burn rating was a visual
rating of each plot. All ratings were made on a scale of 1 to 9, with 1 = dead turf and 9 = no burn.
Recovery quality was a visual rating of each plot. This rating was also based on a scale of 1 to 9, with
1 = straw brown turf, 9 = green turf and 6.0 a minimum acceptable level.
The first burn treatment was made in late spring. As stated above, N rates for CORON on the first
treatment date were 2 and 4 lb N/1000 ft2. The data shows that 4 lb of N applied as CORON can
cause a great deal of burn (Table 27). The CORON treatment at the 2 lb N rate showed less burn
than the urea treatment at a 2 lb N rate. The water rate had no effect on burn potential for this
application. The recovery rate of the burn plots was exceptional. The CORON treatments containing 4
lb N rates produced a very dark green turf by mid-August.
The second burn treatment was made in midsummer. Urea caused immediate burn. The plants
quickly outgrew the foliar burn. The common bluegrass cultivars coupled with excessive rains
probably helped decrease the burn effect. CORON caused very little burn after this treatment (Table
28). Regardless of N source, the 2 lb N rate caused greater burn, but it had a better recovery rate
than the 1 lb N rate. CORON-treated plots generally recovered better than urea treated plots.
While water rate did not affect initial burn, it did affect the recovery rate. Plots treated with the 3 to 5
gal water rate recovered better than plots treated with the 1 gal water rate.
The last treatment date was intended for cooler fall weather. However, September was the hottest,
driest month in during 1990. Urea-treated plots had a greater burn rate than CORON treatments
(Table 29). In addition, urea at the 2 lb N rate had the most severe burn, while CORON at the 2 lb N
rate had the best overall rating on the second and third rating date. The 2 lb N rate recovered better
from the burn and the water rates of 3 and 5 gal had better recovery rates.

56

In summary, CORON can cause severe burn if applied at excessively high N rates (4 lb N). However,
even at these high rates, the recovery of plants treated by CORON was excellent. In contrast, urea
caused severe burn but didn’t recover as well as CORON. In addition, it is best to use a 3 or 5 gal
water rate when using urea.
CORON Response Study: This study was designed to compare the length of response of 2 N
sources (CORON 28-0-0 and Nutriculture 28-8-18) and 3 N rates (0.1, 0.2, 0.3 lb N) on a high sand
content green. This study was conducted on a USGA green with a rootzone mixture of 80% sand,
10% peat, and 10% silt. The pH of the green was 8.3; P and K levels were low. Two lbs I^O were
applied to the entire green on June 10, 1990. The turfgrass species was (Creeping Bentgrass) Agrostis
palustris L. Fertilizer applications were made on June 17, July 27, and August 8. Each fertilizer was
applied with 3 gal water/1000 ft2. Each plot measured 5 ft by 5 ft and was replicated 3 times in a
randomized, complete-block design. The plots were maintained at a 1/4 in mowing height and
irrigated as needed.
Visual quality ratings were taken after each treatment application until there were no visible treatment
effects. Ratings were made on a scale of 1 to 9 with 1 = to dead, straw brown turf and 9 = dark
green dense turf.
Figures 3, 4, and 5 show that CORON applied at 0.3 and 0.2 lb N rates produced the best quality turf
in this study. While CORON treatments produced higher ratings than the Nutriculture treatments, all
treatments will produce an acceptable quality turf. The 0.11b N rate of Nutriculture showed less then
unacceptable quality rating only twice in this study.
In summary, CORON provided a better quality turf than Nutriculture. The CORON provided better
efficacy because it is most likely not as mobile as the Nutriculture.

57

Table 27. Effects of fertilizer source, fertilizer, rate and water rate on leaf burn and recovery of
fertilizer applied on September 5, 1990

Recovery
Quality4

Visual Burn Rating3
Fertilizer
Source

Fertilizer
Rate1

Water
Rate23
4

6/30

7/3

7/6

8/14

CORAN

2

1

6.7

5.7

6.3

7.7

CORAN

2

3

7.0

5.3

6.7

8.3

CORAN

2

5

7.7

5.3

6.3

7.7

CORAN

4

1

5.3

3.0

4.0

8.7

CORAN

4

3

5.0

3.3

4.7

8.7

CORAN

4

5

4.3

2.7

3.7

9.0

Urea

1

1

6.7

6.7

7.3

6.0

Urea

1

3

6.0

6.7

8.0

5.7

Urea

1

5

7.0

7.3

7.7

6.3

Urea

2

1

4.3

4.7

6.0

6.0

Urea

2

3

4.3

4.0

4.7

7.0

Urea

2

5

4.7

4.3

5.0

7.0

1.3

1.4

2.3

1.8

LSD (0.05)

1. Fertilizer rate = pound N/1000 ft2.
2. Water rate = gallon of water/1000 ft2.
3. Burn rating = a visual rating of each plot. All ratings were made on a scale of 1 to 9, with 1 =
dead turf and 9 = no burn.
4. Recovery quality is a visual rating of each plot. The rating is based on a scale of 1 to 9, with 1 =
straw brown turf and 9 = green turf and 6.0 is a minimum acceptable level.

58

Table 28. Effects of fertilizer source, fertilizer rate, and water rate on
leaf
burn and recovery of fertilizer applied on September 5, 1990.

Recovery
Quality^

O

Visual Burn Rating^
Fertilizer
Rate^

Water
Rate^

6/30

7/3

7/6

8/14

CORON

i

i

7.3

7.3

6.7

6.3

CORON

i

3

8.0

7.7

6.7

7.3

CORON

i

5

7.7

7.7

7.0

7.0

CORON

2

1

7.0

8.3

8 .0

8 .0

CORON

2

3

7.0

7.7

8.3

8.3

CORON

2

5

7.0

6.3

8.3

8.3

Urea

1

1

5.0

7.3

6.7

6 .0

Urea

1

3

6 .0

7.7

7.7

6.3

Urea

1

5

5.3

6.7

7.3

6.3

Urea

2

1

3.7

7.0

Urea

2

3

3.3

7.0

8.3

8.3

Urea

2

5

4.0

7.0

8.7

8.3

OO

Fertilizer
Source

8.3

LSD (0.05)
(F.S.)

0.9

NS

0.3

0.3

LSD(0.05)
(F.R.)

0.9

NS

0.3

0.3

LSD (0.05)
(W.R.)

NS

NS

0.4

0.4

1.
2.
3.
4.

Fertilizer rate — pound N/1000 ft^.
Water rate = gallon of water/1000 ft^.
Burn rating = a visual rating of each plot. All ratings were made on a
scale of 1 to 9, with 1 = dead turf and 9 = no burn.
Recovery quality = a visual rating of each plot.
The rating is based on a
scale of 1 to 9, with 1 = straw brown turf and 9 = green turf and 6.0 is a
minimum acceptable level.

59

Table 29. Effects of fertilizer source, fertilizer rate, and water rate on leaf burn and recovery of fertilizer
applied on September 5, 1990.

Recovery
Quality4

Visual Burn Rating3
Fertilizer
Source

Fertilizer
Rate1

Water
Rate23
6
5
4

9/7

9/15

9/20

9/28

CORON

1

1

7.0

8.7

8.0

7.3

CORON

1

3

6.7

8.3

8.0

7.7

CORON

1

5

7.3

7.7

8.3

7.0

CORON

2

1

7.3

9.0

9.0

7.0

CORON

2

3

7.0

8.7

9.0

7.7

CORON

2

5

6.3

7.3

9.0

8.7

Urea

1

1

6.0

7.3

8.0

7.3

Urea

1

3

6.7

8.0

8.3

8.0

Urea

1

5

7.0

8.7

8.7

7.3

Urea

2

1

6.7

7.0

7.7

6.7

Urea

2

3

5.7

5.7

7.7

8.7

Urea

2

5

5.3

7.3

8.7

8.7

*5

**6

*

NS

NS

NS

NS

★

LSD
(W.R.)

NS

NS

NS

★★

LSD
(F.S.XF.R.)

NS

★

★★

NS

LSD
(F.S.)
LSD
(F.R.)

*

1. Fertilizer rate = pound N/1000 ft2.
2. Water rate = gallon of water/1000 ft2.
3. Burn rating = a visual rating of each plot. All ratings were made on a scale of 1 to 9, with 1 =
dead turf and 9 = no burn.
4. Recovery quality = a visual rating of each plot. The rating is based on a scale of 1 to 9, with 1 =
straw brown turf, and 9 = green turf, and 6.0 a minimum acceptable level.
5. * = significant at a 0.10 level.
6. ** = significant at a 0.05 level.

60

61

Figure 3. Effects oí N source and N rate on visual quality
of Creeping Bentgrass from 6-4 to 7-8.

62

Figure 4. Eííects oí N source and N rate on visual quality
oí Creeping Bentgrass from 8-1 to 8-16.

63

Figure 5. Eiiects oi N source and N rate on visual quality
oi Creeping Bentgrass from 9-10 to 9-28 and yearly average.

Natural Organic Trial

M. L. Agnew and S. M. Kassmeyer

A natural organic nitrogen trial was established in 1989 on a four-year-old ’Park’ Kentucky bluegrass
(Poa pratensis) stand. The grass was mowed weekly with clippings removed, dried, and weights
recorded. Irrigation was applied at a rate of 1 in of water/week. Rainfall was excessive from May
through mid August. The area was subjected to high temperature stress only in the fall.
The purpose of this study was to compare nine natural organic fertilizers to urea. Treatments included
Bioturf 10-4-4, Sustane medium grade 5-2-4, Sustane fine grade 5-2-4, ISU experimental (10% N),
Milorganite 6-2-0, Natures Preference 5-3-5, Ringer 10-2-6, Ringer 6-1-3, Howe 5-2-5 (added in 1990),
Urea 46-0-0, and a control. All fertilizers were applied at 1 lb N/1000 ft2 on May 15, June 15, August
15, and September 15, 1989. This study was replicated three times in a randomized, complete-block
design. Individual plot dimensions were 5 ft by 10 ft.
Data collected during the summer of 1990 included visual quality, clipping yield, and thatch
development. All plots were rated weekly on a visual scale of 9 to 1. A rating of 9 is equal to a darkgreen, dense turf, whereas a rating of 1 equals a straw-brown turfgrass stand. A rating of 6.0 was
used as the minimum acceptable level of quality. Clipping yields were collected on a weekly basis or
when enough grass was present to collect. Clippings were collected by removing all leaf tissue above
2 in within a 21 in by 10 ft area (17.5 ft2) down the center of each plot. Clippings were placed in
paper sacks and dried. Weights were recorded as grams/17.5 ft2. Core samples were collected in
July, 1990, and compressed thatch depth was measured in millimeters. The core samples were taken
to the lab and percentage organic matter in the thatch layer was determined.
Clipping yield data is presented in Table 30. Plots fertilized with urea produced the most clippings.
Unfertilized control and plots fertilized with Natures Preference produced the fewest clippings. For
other fertilizers, Ringer products, Sustane fine, and ISU Experimental produced high quantities of
clippings; Milorganite and Bioturf produced moderate amounts of clippings; Sustane medium and
Howe 5-2-5 produced the smallest amount of clippings.
Visual quality ratings are presented in Table 31. Urea had the highest overall quality while the control
and Nature’s Preference had the lowest quality ratings. Milorganite, Bioturf, Ringer products, Sustane
fine, and ISU Experimental had the best overall quality ratings.
The excessive rainfall in 1990 provided excellent growing conditions. Urea-treated plots grew
excessively as indicated by the high level of clippings that were produced. This excessive growth led
to a higher quality level, and the need to mow more frequently. All natural organic nitrogen sources
reduced clipping yields significantly, and all but Natures Preference provided adequate quality for
most of the growing season.
The performance of Howe 5-2-5 needs to be evaluated in proper context. This fertilizer source was
not used in 1989. Therefore, this product is not discussed in this report because less nitrogen has
been applied per plot.

64

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8

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Table 31. Natural Organic Trial - Visual Quality.

The Effects of 13 Granular Nitrogen Fertilizer Sources
on the Growth and Quality of ’Park’ Kentucky Bluegrass
M. L. Agnew and S. M. Kassmeyer
The purpose of this study was to evaluate the performance of 13 granular nitrogen fertilizer sources.
The treatments included urea, ammonium sulfate, sulfur coated urea (CIL), sulfur coated urea (TVA),
sulfur-coated urea (Scotts), Blue Chip, IBDU (fine), UFC ammonium sulfate, Nutralene, Scotts 41-0-0,
Milorganite, Restore 10-2-6, ISU Experimental (natural organic), and a control with no fertilizer applied.
All treatments were applied at 1 lb N/1000 ft2 on May 15, June 15, August 15, and September 15,
1989, to a ’Park’ Kentucky bluegrass. This study was replicated three times in a randomized,
complete-block design. Individual plot sizes were 4 ft by 10 ft.
All plots were mowed at a 2 in height with all clippings removed. The plots were irrigated with a
minimum of 1.5 in water/growing week when sufficient rains did not occur. In 1990, rainfall was
excessive from May through mid August.
Data collected included visual quality and clipping yields. Visual quality is based on a scale of 1 to 9;
with 9 equal to dark-green turfgrass, 6 equal to minimum quality, and 1 equal to straw-colored turf.
Clipping yields were obtained at each mowing by collecting all leaf tissue over 2 in within a 1.75 ft by
10 ft (17.5 ft2) area. Clippings were dried and weights recorded.
Visual quality data is included in Table 32. Average quality was determined as the means of all quality
ratings less the March 29 and April 20 data. None of the fertilizer sources exhibited an average
quality less than 7. Sulfur-coated urea (Scotts), sulfur-coated urea (TVA), and Restore 10-2-6 all had
an average quality rating greater than 8. The March 26 and April 20 data reflect spring green-up.
Sulfur-coated urea (Scotts), milorganite, and Restore 10-2-6 were the only treatments to provide
quality ratings above 6 during the early spring.
Clipping yield data is included in Table 33. The methylene ureas (Blue Chip, Nutralene, and Scotts
41-0-0) exhibited the lowest clipping yields, while sulfur-coated urea (Scotts), and Restore 10-2-6
produced the greatest clipping yield. Urea-treated plots had low clipping yields when compared to
other fertilizer trials.
To calculate the amount of dried clippings that would be removed for 1000 ft2 in mowing, simply
divide the total amount of clippings by 8. For example, Restore 10-2-6 produced 52.5 lb of dried plant
tissue for 1000 ft2 in one growing season, while Blue Chip produced 25.5 lb of dried plant tissue for
1000 ft2

67

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The Effects of Synthetic and Natural Organic Nitrogen Source
and Core Cultivation on Turfgrass Growth Under Traffic Stress

M. L. Agnew

This study was initiated at the Iowa State University Horticulture Research Station in Ames, Iowa,
during the spring of 1989. The objective of this study was to observe the effects of six fertilizer
sources and core cultivation on turfgrass quality, clipping production, root density, and physical soil
properties.
The six fertilizer sources include:
1.
2.
3.
4.
5.
6.

Urea 46-0-0
IBDU 31-0-0
Ringer Turf Restore 10-2-6
Ringer Green Restore 6-1 -3
Milorganite 6-2-0
Ureaform (Blue Chip) 38-0-0

(Synthetic fast-release organic)
(Synthetic slow-release organic)
(Natural organic)
(Natural organic)
(Natural organic)
(Synthetic slow-release organic)

Urea was applied at 1 lb N/1000 ft2 on May 15, June 15, August 15, and September 15, 1990. All
other fertilizers were applied on May 15 and August 15 at 2 lb N/1000 ft2.
Core cultivation treatments consisted of two passes with a Ryan Lawn-Aire 28 just before fertilization
on May 15 and August 15. This resulted in approximately 20 holes/ft2/treatment.
Traffic stress was initiated on May 15 and consisted of five passes each Friday with a water-filled
smooth roller. Traffic stress resulted in a combination of wear and soil compaction. Due to the
extremely wet summer of 1990, the predominant traffic stress was soil compaction.
One undisturbed soil sample was collected from each plot on October 15. Total porosity, air-filled
porosity, bulk density, and soil strength were determined for each sample.
Fertilizer source had little effect on soil physical properties (Table 34). While there was a difference in
bulk density at the 10% level of probability, the differences were minor. The effects of cultivation
treatments were much more pronounced.
Core cultivation and traffic stress had a significant effect on soil physical properties. Plots that were
core cultivated had a soil strength of 2.9 and an air-filled porosity of 20.2%, while plots that were not
cultivated had a soil strength of 3.2 and an air-filled porosity of 18.9% This shows the ability of core
cultivation to alleviate soil compaction. Soils receiving weekly traffic had greater soil strength (3.4 vs
2.8), increased bulk density (1.42 vs 1.31), and lower total pore space (38.6 vs 40.0) than soils that
received no traffic. There were no interactions between variables.
Visual quality ratings and clipping yield samples were collected on a weekly basis. Shoot density,
thatch, and root density samples were collected on June 30. Visual ratings were based on a visual
scale of 9 to 1. A rating of 9 equals a dark green, dense turfgrass, whereas a rating of 1 equals a
straw-brown turfgrass stand. A rating of 6 was used as the minimum acceptable level of quality.
Clippings were collected by removing all leaf tissue over 2 in within a 21 in by 5 ft area (8.75 ft2) down
the center of each plot. Clippings were placed in paper bags and dried. Weights were recorded as

70

grams/8.75 ft2. Shoot density was determined by counting the number of tillers/15 in2 at three
locations for each plot. Thatch depths were measured by taking two 3-in diameter plugs from each
plot. The thatch was compressed with a 2 kg weight and depth was measured as mm. No difference
was found for either shoot density or thatch development. Hence, the data is not shown. Root
density samples were collected by taking six cores from each plot with a 1-in diameter soil probe.
Samples were divided into 5 cm segments. Soil was washed from the roots, which were dried and
ashed. Data is reported as mg of organic matter/25 cm3.
Fertilizer Source:

The effect of fertilizer source on visual quality is presented in Table 35. Urea had an overall quality of
7.8, followed by Restore 10-2-6 (7.2), Restore 6-1-3 (7.0), Milorganite (6.7), Blue Chip (6.5), and IBDU
(6.4). Plots treated with urea, IBDU, and Restore 6-1-3 exhibited a quicker spring green-up. Following
the first fertilizer application for 1990, all treatments provided acceptable quality. While there were
treatment differences on each measurement date, no one fertilizer maintained consistently better
quality over the others.
The effect of fertilizer source on clipping yields is presented in Table 36. Urea produced the greatest
amount of clippings (181.1 g), followed by Restore 10-2-6 (172 g), Restore 6-1-3 (162 g), Milorganite
(129 g), IBDU (98 g), and Blue Chip (93 g). Treatments with higher yields corresponded to the better
quality ratings. Urea-treated plots demonstrated quicker growth in the spring. By early June, both
Restore-treated plots produced the greatest amount of clippings. After mid-June, the uresttreated
plots produced the most clippings.
There were no major effects of fertilizer on root density (Table 37). However, minor differences did
occur at the 10% level in the 10 to 15 cm soil zone. Milorganite had the greatest root mass followed
by Restore 10-2-6 and Blue Chip.
Core cultivation:

The effects of core cultivation were evident on several measurement dates (Table 35). Core cultivation
improved quality on June 13, June 20, July 25, August 1, and August 14. Core cultivation adversely
affected quality on September 19. The high temperatures in September coupled with a more open
turf due to core cultivation may well have been responsible for the lower quality in September.
Core cultivation had very little effect on clipping yields (Table 36) and root density (Table 37).
Traffic Stress:

<

Overall, traffic decreased visual quality of Kentucky bluegrass (Table 35). Traffic reduced visual quality
on March 29, April 20, June 20, June 26, August 1, August 8, August 14, September 11, and
September 19. Interestingly, visual quality was greater for traffic plots on May 13, 2 days prior to the
onset of traffic treatments.
Traffic had a minor effect on clipping yields (Table 36) and increased surface rooting (Table 37). An
increase in surface rooting is common on sites that are heavily compacted. However, it is rare that
these differences show up in field studies.

71

i

Table 34. The effects of fertilizer, core cultivation, and traffic on soil properties.
Fertilizer
Source

Core

Traffic

Soil
Strength

Bulk
Density

Total Pore
Space

Air-Filled
Pores

Urea

Yes

Yes

3.1

1.42

36.9

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Yes

No

2.9

1.27

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Urea

No

Yes

3.7

1.47

38.4

19.6

Urea

No

No

2.5

1.23

38.8

18.6

IBDU

Yes

Yes

3.1

1.43

38.3

20.6

IBDU

Yes

No

2.8

1.33

39.6

18.9

IBDU

No

Yes

3.7

1.40

38.1

19.6

IBDU

No

No

3.3

1.38

38.7

17.5

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Yes

Yes

3.4

1.41

39.9

20.6

Restore 10-2-6

Yes

No

2.7

1.34

40.5

21.8

Restore 10-2-6

No

Yes

3.9

1.46

40.3

18.4

Restore 10-2-6

No

No

2.6

1.33

38.1

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Yes

Yes

3.3

1.50

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Milorganite

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No

2.8

1.41

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Yes

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37.5

19.5

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No

No

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39.0

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39.5

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Yes

No

2.3

1.24

43.3

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Yes

3.3

1.37

38.0

20.9

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No

No

3.4

1.27

41.4

18.3

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Yes

Yes

2.8

1.34

41.7

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Blue Chip

Yes

No

2.6

1.29

37.4

18.4

Blue Chip

No

Yes

3.8

1.42

36.4

19.6

Blue Chip

No

No

3.1

1.36

38.9

19.0

LSD (FERT)

N.S.

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N.S.

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0.2

0.03

1.3

N.S.*

* = significant at a 10% level.

72

= significant at 10% level.

Table 35. Effects of fertilizer, core cultivation, and traffic on plant quality

74

= significant at 10% level.

Table 35. (continued)

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Table 36. The effects of fertilizer, core cultivation, and traffic on clipping yield

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Depth (cm)
Fertilizer
Source

Core

Traffic

0-5

5-10

10-15

15-20

Urea

Yes

Yes

105.0

33.4

23.3

7.3

Urea

Yes

No

121.3

27.5

22.9

6.6

Urea

No

Yes

143.0

51.0

23.7

3.5

Urea

No

No

124.4

43.6

16.7

1.2

IBDU

Yes

Yes

135.8

57.2

17.5

9.5

IBDU

Yes

No

115.0

36.5

20.3

5.8

IBDU

No

Yes

156.1

47.3

16.8

12.1

IBDU

No

No

107.3

30.9

15.9

11.8

Restore 10-2-6

Yes

Yes

136.8

65.5

22.5

10.2

Restore 10-2-6

Yes

No

117.0

39.8

22.0

5.6

Restore 10-2-6

No

Yes

174.1

63.0

36.5

12.1

Restore 10-2-6

No

No

133.8

52.5

20.8

15.4

Milorganite

Yes

Yes

115.7

56.6

30.0

12.3

Milorganite

Yes

No

169.7

40.0

35.5

7.5

Milorganite

No

Yes

129.0

71.3

32.6

7.3

Milorganite

No

No

119.7

44.3

12.9

10.7

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Yes

Yes

124.3

50.9

24.8

4.9

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Yes

No

103.0

44.0

13.0

9.4

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No

Yes

117.8

46.7

12.5

8.6

Restore 6-1-3

No

No

110.6

45.7

11.1

5.3

Blue Chip

Yes

Yes

178.1

33.7

21.5

10.7

Blue Chip

Yes

No

114.8

40.8

23.2

8.4

Blue Chip

No

Yes

127.3

62.4

19.8

7.5

Blue Chip

No

No

116.5

45.9

26.4

6.2

LSD (FERT)

N.S.

N.S.

N.S.*

N.S.

LSD (CORE)

N.S.

N.S.*

N.S.

N.S.

LSD (COMP)

17.9

8.1

N.S.

N.S.

* = significant at the 15% level.

76

The Evaluation of 13 Granular Nitrogen Sources on
the Quality of Bentgrass Greens
M.L. Agnew and S.M. Kassmeyer
The purpose of this study was to evaluate the performance of 13 granular nitrogen fertilizer sources.
The treatments are listed in Table 38 and Table 39. The treatments were applied at a rate of 0.5 lb
N/1000ft2 on May 29, June 26, July 24, and August 20 to a creeping bentgrass ’Pencross’/Poa annua
green. The testing area was located at the Hyperion Field Club, Johnston, Iowa. The plot consisted
of a randomized, block-design replicated three times.
The plots were mowed daily and irrigated as needed.
Visual quality data was collected weekly. Visual quality ratings were based on a scale of 1 to 9, with
one being equivalent to straw brown turf and 9 equal to dense dark green turf (Table 38 and Table
39).
The fertilizers containing higher soluble nitrogen, Country Club, (Country Club + NIAD, Scotts +
Minors, and Scotts + Manganese) had consistent average visual quality ratings above 6.0, dipping
below 6.0 one or two times. Scotts + Manganese had the highest overall ratings and remained deep
green in color during the entire 1990 testing season. The second-most noticable dark green turf was
obtained by using Scotts + Minors. Both fertilizers maintained a 7.0 or above rating for most of the
1990 testing season.
The rest of the fertilizers used were slow release nitrogen sources and showed ratings of 5.0 or 6.0
the first part of June. From mid-July through October the slow-release fertilizers showed turf with
ratings of at least 6.0 or above.

1

77

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Table 39. The comparison of fertilizer sources on visual qaulity of bentgrass from August 7 to October 2.

The Effects of Core Cultivation on the
Performance of Four Nitrogen Fertilizers
M. L. Agnew and S. M. Kassmeyer
This study compares the effects of core cultivation on the performance of four granular nitrogen sources.
The study was established of May 20, 1988, and terminated in the spring of 1991. The turf was ’Park’
Kentucky bluegrass that was established in the fall of 1987. The grass was mowed weekly at 2 in and
all clippings were removed. Irrigation was applied at a rate of 1.5 in/week.
Treatments included five nitrogen treatments and two cultivation treatments. The fertilizer included
Milorganite, Blue Chip, Scott’s methylene urea (41-0-0), ISU experimental (natural organic), and a nonfertilized control. Cultivation treatments included core cultivation and non cultivated control. Treatments
were applied on May 22, June 27, and August 15,1990. Fertilizer was applied immediately following each
cultivation treatment.
This study was replicated three times in a randomized complete-block design with a two-way factorial.
Individual plot sizes were 5 ft x 10 ft.
Data collected included visual quality and clipping yields. Visual quality is based on a scale of 1 to 9, with
1 equivalent to straw brown turfgrass and 9 equivalent to a dark green, dense turfgrass stand. A rating
of 6.0 was the minimum acceptable quality level. Clipping yields were collected on a weekly basis by
removing all leaf tissue above 2 in in a 21 in x 10 ft area (17.5 ft2) down the center of each plot. Clippings
were placed in paper sacks, dried, and weights recorded as grams/17.5 ft2.
Visual quality data is presented in Table 40. There were no differences between cultivation treatments
or fertilizer x cultivation interaction. All fertilizer sources consistently had better quality than the untreated
control. Scott’s 41-0-0 fertilizer greened up quickest in spring and maintained acceptable quality
throughout the growing season. ISU Experimental Fertilizer performed very similarly to the Scotts product.
Milorganite and Blue Chip had a consistently lower quality during the spring and summer. Milorganite
quality was equivalent to the ISU Experimental product in the fall.
Clipping yield data is presented in Table 41. ISU Experimental had the greatest total clipping production,
followed by Scotts 41-0-0, Milorganite, and Blue Chip. All fertilizers had greater clipping production when
compared to the non-fertilized control. Core cultivation had a negative effect on May 22 and June 20.
While this effect was noted on those days, it does indicate that cultivation prior to dry weather does have
an effect on clipping production.

80

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Com parison of Kentucky Bluegrass Response to
Agriform, IBDU, Sulfur Coated Urea, and Urea
R. W. Moore and N. E. Christians
Four nitrogen sources were evaluated for maintenance fertilization of Kentucky bluegrass. This
evaluation included one quick-release source, urea, and three slow-release materials, IBDU (fine),
sulfur-coated urea (CIL), and Agriform. Urea, IBDU, and sulfur coated urea are commonly used turf
fertilizers. Agriform (34-0-7) is a blend of 70% coated and 15% uncoated urea. The coated fraction is
further divided into 3 to 4 month resin-coated urea and 8 to 9 month resin-coated urea. The balance
of this fertilizer is an uncoated potassium sulfate.
The turfgrass used in this study was ’Park’ Kentucky bluegrass, which was maintained at a cutting
height of 2 in. The plots were irrigated regularly at 1 in of moisture/week when needed. A
randomized, complete-block design with three replications was used. Each plot measured 4 ft by 8 ft,
and each replication was separated by a 2 ft border.
Each product was applied with two application schedules (Table 42). The Agriform (34-0-7), IBDU,
and sulfur-coated urea were applied at 4 lb N/1000 ft2 in one application on April 15, 1989, and at 4 lb
N in three split applications of 1.3 lb each. The split applications were made on April 15, June 15, and
August 15. Urea was applied on a balanced schedule at 1.3 lb/1000 ft2 on the same dates and on a
standard four application schedule of 0.75 lb of N on April 15 and May 15, 1 lb of N on August 15,
and 1.5 lb on September 15. Potassium sulfate was applied to all treatments not containing
potassium, at a rate equivalent to that provided by Agriform.
Data taken included visual quality and clipping yields. The visual quality rating was based on a 9 to 1
scale; 9 = best quality, 6 = acceptable quality, and 1 = no live grass. Clipping yields were obtained
by using a 21 in push mower and making one swath through the 8 ft length of each plot. This resulted
in a 14 ft2 area in which clippings were sampled.
The grass that received the Agriform product at 4 lb/1000 ft2 in mid-April (Graph 6, Table 42 & 43)
showed lowerer overall quality ratings than SCU but maintained better quality ratings than IBDU. This
treatment also had better quality in May, June and July, but not August or September. The grass
which received three equal applications of Agriform, in mid-April, mid-June and in mid-August, had a
slower spring start but more acceptable or near acceptable quality ratings in July, August and
September.
The IBDU-treated grass(Fig 6, Tables 42 & 43) at 4 pounds of N per 1000 ft2 in a mid-April application
demonstrated acceptable quality ratings in late May and through June only. The IBDU-treated grass,
at three equal application rates in mid-April, mid-June, and mid-August, demonstrated acceptable
quality ratings in early April, but not again until late July and in August and September.
The grass treated with SCU (Figure 6, Tables 42 & 43) at 4 lb of N per 1000 ft2 in mid-April had the
most consistent acceptable quality ratings. Only in early April, late August, and in September did
quality ratings fall below an acceptable level. The grass treated with three equal applications, had
accceptable quality ratings in early April, late July, and again in August and September.
The balanced-urea-treated grass, (Fig 6, Tables 42 & 43) demonstrated acceptable quality in late April
and May, and again in late August and September. The standard-urea-treated grass responded
similarly to the balanced program with slightly higher quality ratings.
The LSD readings (Table 43) suggest there are significant differences in quality ratings among the
eight treatments.

83

Overall clipping yields were not significantly different. The Agriform-treated grass at the 4 lb in one
application rate demonstrated slightly higher yields on the late fall collection dates. The SCU at the
split rate demonstrated slightly higher yields throughout the season. Again, these differences were
not significant.
Agriform at the 4 lb one application rate, (Figure 6, Table 43) had lower overall quality ratings than
SCU but maintained better quality ratings than IBDU. This is probably due to the combination of quick
and resin-coated ureas used. This also suggests the reason for a higher midsummer quality rating.
This rate was significantly greater than all of the split applications at the midsummer June 26
collection date (Table 43). Agriform applied at the split rate (Table 42) had somewhat higher quality
ratings in the last three data collection dates (Table 43). This is probably due to the slower-release
resin-coated ureas in the Agriform blend that released at the end of the season.
The addition of more water-insoluble nitrogen to the formula would possibly increase the early season
response of the grass.
Very little difference was demonstrated in clipping yield. In fact, the data suggests no significant
differences (Fig 7, Table 44). The large increase on the August 22 collection date was likely due to a
lower than normal mower height setting at the time of collection.

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RATINGS BASED ON 9-1 RATING.
9=BEST Q UALITY, 6=ACCEPTABLE QUALITY AND
1-NO LIVE GRASS

QUALITY RATINGS

SIERRA TRIAL 1990

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MURP Studies
M. L. Agnew and S. M. Kassmeyer
Tolerance Study
In the spring of 1990 a study was established in cooperation with O. M. Scott & Sons Company to
compare the effects of four nitrogen formulations on a four-year-old stand of ’Ram I’ Kentucky
bluegrass. Prior to any fertilizer treatments, the site was core cultivated and power raked to provide a
uniform testing area. Individual plots measured 3 ft X 10 ft and the treatments were replicated 3 times
in a randomized complete block design. The plots were mowed weekly with one mower pass and all
leaf tissue above 1 1/2 in collected. Irrigation was added to reduce plant stress. However, 1990 was
an extremely wet year and these conditions may have placed plants under waterlogged conditions for
short periods of time. The effects of the waterlogged soil conditions became evident in September.
Temperatures were hot and plant growth declined due to probable root dieback caused by wet soils.
Treatments
Nitrogen fertilizers used in this study include: three methylene urea formulations (39-0-0, 41-0-0, and
42-0-0) and urea (46-0-0). The fertilizers were applied at a rate of 1 lb N/1000 ft2 on May 23, June 29,
and August 14.
Data Collected
Data collected included fresh clipping weight and visual quality rating. Clippings were collected each
week or when growth warranted clipping removal. Clippings were collected with a Toro rotary mower
and placed in bags. Fresh weights were recorded immediately after mowing. Visual quality ratings
were collected weekly prior to clipping removal. Ratings are based on a scale of 9 to 1. A rating of 9
is equivalent to a dark-green turfgrass stand, 1 is equal to dead, straw-brown turf and 6 is equivalent
to a minimum acceptable level.
Results - Quality Ratings
Visual quality ratings are shown in Tables 45, 46, and 47. Table 45 contains the data from the first
fertilizer application. Table 46 contains data from the second fertilizer application and Table 47
contains data from the third fertilizer application. Fertilizer carryover from the previous dry seasons
was quite noticeable. This was reflected in the consistently higher quality ratings for control plots
before August 28. Only slight differences appeared when comparing urea (46-0-0) and the two
methylene ureas (42-0-0 and 41-0-0). However, the quality of methylene urea (39-0-0) was
consistently lower than urea. Except for the September 19 rating all fertilizer treatments rated above
an acceptable level. During this time period, plots were heavily stressed due to high temperatures.
Results - Fresh Weights
Fresh weight data is shown in Fig 8, 9, 10, and 11. Fig. 8 shows the data collected after the first
fertilizer application. There were few differences between the methylene ureas and urea. Fig. 9 shows
the data collected after the second fertilizer application. Fresh clipping weights were statistically the
same for urea (46-0-0) and methylene ureas (42-0-0 and 41-0-0). However, the urea treatment
consistently had the highest value. The fresh clipping weights of methylene urea (39-0-0) were
statistically less than urea for this period. Fig. 10 shows the data collected after the third fertilizer
application. Due to hot, dry weather in the fall growth slowed, causing a decrease in mowing
frequency. (The low mowing height and dry, hot conditions stressed the turf.) Dollar spot infested the
testing area in mid-August which also slowed growth. Fig. 11 shows the total fresh clipping weights

90

for 1990. Urea (46-0-0) and methylene urea (42-0-0) produced the greatest amount of vegetative
growth, while methylene urea (39-0-0) produced the least amount of growth.
Summary
The weather in 1990 was very wet. This provided excellent conditions for utilization of nitrogen
applied as urea. The probable loss of nitrogen due to volatilization or leaching was low since
fertilizers received water after application and the soils were silty clay loams that are not prone to
leaching. The overall green color for urea-treated plots was good throughout the season. The
addition of urea increased clipping yields by 128% over the non-fertilized control, while the addition of
39-0-0 methylene urea increased clipping yields only by 32% over the non-fertilized control.
It is important that this study be duplicated in a year when weather conditions are “more normal" (i.e.
hot and dry in summer and best growing conditions in spring and fall). Plans are to repeat this study
in 1991 on the same site .

Bum Study
Using the same fertilizers (42-0-0, 41-0-0, 39-0-0, and 46-0-0) a study was conducted to examine the
burn potential of different nitrogen formulations using 3 and 6 lb N rates.
Figs. 12 and 13 show burn ratings as they appeared 7 and 10 days after the application. Burn ratings
were taken on a scale of 9 to 1, with 9 equivalent to dark-green dense turf and 1 equal to a strawbrown dead turf. Using this scale, 6 is equivalent to a minimum acceptable level.
Methylene urea (42-0-0) produced a high amount of burn when applied at 6 lb N/1000 ft2. The burn
was immediate, showing a rating of 4.3. Methylene urea (42-0-0) applied at 3 lb N/1000 ft2 showed
very little burn, while the 3 and 6 lb N rates of the 41 -0-0 and 39-0-0 showed no burn. Urea (46-0-0)
applied at the 3 lb and 6 lb N rates showed severe burn immediately after application. The 3 lb N rate
burn did not appear as severe but was still very evident.

91

Table 45. Visual Quality Ratings from May 30 to June 26, 1990.

Fertilizer

5/30

6/4

6/13

6/20

6/26

7/3

7/13

7/19

7/25

Control

6.7

5.0

6.0

6.7

7.7

6.3

7.0

6.7

7.0

39-0-0

7.0

6.3

6.0

7.3

8.0

6.7

7.0

7.7

8.0

41-0-0

7.0

6.7

7.0

8.3

7.3

7.7

8.0

8.7

8.7

42-0-0

7.0

7.3

7.0

7.7

7.3

9.0

8.7

9.0

8.7

46-0-0

7.0

7.7

8.3

8.7

9.0

9.0

9.0

9.0

8.7

LSD

1.5

1.0

2.4

1.5

1.4

0.9

1.6

0.6

0.9

Table 46. Visual Quality Ratings from July 3 to August 14, 1990.
Fertilizer

8/1

8/8

8/14

8/20

8/28

Control

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7.7

6.7

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39-0-0

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7.7

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7.3

6.7

41-0-0

8.3

8.3

8.0

8.0

7.7

42-0-0

8.7

8.7

8.7

9.0

9.0

46-0-0

8.7

9.0

9.0

9.0

9.0

LSD

1.0

0.9

1.2

0.6

0.7

Table 47. Visual Quality Ratings from August 20 to October 19,1990.
Fertilizer

9/6

9/11

9/19

10/1

10/8

10/19

Control

5.3

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5.0

5.0

5.7

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5.7

6.0

7.0

7.0

41-0-0

6.7

8.0

5.7

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7.0

7.0

42-0-0

7.7

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6.7

6.7

7.0

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46-0-0

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8.3

6.3

7.3

7.7

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LSD

0.8

1.4

1.4

0.9

0.7

0.7

92

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Figure 8. Clipping yields irom June 4 to June 27.

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Figure 13. Burn rating 10 days alter application.

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Crabapples
J. K. lies

crab apple (krab’ap I) n. 1. any of several species of terrible little trees well known for their
propensity to litter the ground with rotting fruit and defoliate in July. 2. so-called ornamental
trees sold by dishonest nurseries and garden centers. 3. a homeowner’s worst nightmare.
Unfortunately, many homeowners might not see the humor in this tongue-in-cheek definition
of crabapples. Thanks to cultivars such as ’Dolgo’, ’Hopa’, ’Radiant’, and ’Royalty’, which
were planted heavily over the last 20 to 30 years, the public has had ample opportunity to
see trees without leaves in August and experience messy fruit drop. It’s a wonder that
nurseries are able to sell crabapples at all with cultivars such as ’Radiant’ serving as goodwill
ambassadors. Today, most nursery operators are aware that superior cultivars of the genus
Malus exist. These trees produce small, persistent fruit and show excellent disease
resistance. Nurseries and garden centers are obliged to sell these preferred cultivars and
varieties and phase out more troublesome species. Only when this is done will the general
public begin to regain faith in a truly remarkable group of small ornamental trees.
Iowa State University is one of 23 cooperators taking part in the National Crabapple
Evaluation Program (NCEP). Each trial site is currently evaluating over 50 crabapple varieties
and cultivars for disease resistance and outstanding ornamental features. ISU is also
participating in the National Crabapple Introduction Program (NCIP), established to evaluate
new taxa. Cultivars and varieties demonstrating superior qualities at the Ames, Iowa, trial site
are described below.
’Adams’ - Originated in the late 1940s at the West Springfield residence of the late Walter
Adams, former president of Adams Nursery, Westfield, Massachusetts. Trees are rounded
and dense, growing about 20 ft tall with an equal spread. In spring, deep carmine buds open
to single reddish-pink flowers. The light-green foliage exhibits a reddish tinge on new growth
and is only slightly susceptible to powdery mildew. The 5/8 in fruit of ’Adams’ colors a dark
red by the middle of July, but will persist until the following spring. Use the tree in mass
plantings or as a single specimen.
'Candied Apple’ - A popular weeping form growing 10 to 15 ft tall developed at Lake County
Nursery Exchange, Perry, Ohio. Dark red buds open to single, pink flowers in spring and
leaves are dark green with just a hint of brownish-red. The bright cherry red fruit are 5/8 in in
diameter and may persist until late winter. ’Candied Apple’ reportedly has slight to moderate
scab susceptibility; however, this disease has not affected trees in Ames. Use it in place of
the disease-prone weeper 'Red Jade’.
’David’ - Named in 1957 by Arie F. denBoer after a grandson, this round and compact tree
will grow to a height of approximately 20 ft. Flowers are light pink in bud, opening to
moderately fragrant single white blooms. Fruit are 1/2 in in diameter, scarlet red, and very
persistent. Unfortunately, the dense, dark green foliage of ’David’ tends to conceal the
attractive flowers and fruit. This cultivar is only slightly susceptible to scab and fireblight.

99

’Donald Wyman’ - Given the name of the famous horticulturist in the late 1940s, this cultivar
remains a standout among the hundreds of available crabapples. Dark-green foliage is dense
on this tree’s rounded, 15 to 20 ft tall frame. Pink buds open to mildly fragrant single white
flowers and an abundant crop of bright red 3/8 in fruit is produced annually. The persistent
fruit are a welcome addition to bleak winter landscapes. ’Donald Wyman’ is only slightly
susceptible to powdery mildew.
’Harvest Gold’ - This vigorous cultivar grows 15 to 20 ft tall and maintains a neat, upright
habit, perfect for narrow boulevards or other sites where space is limited. Single white
flowers are followed by 3/5 in golden-yellow fruit that remain effective well into December.
’Harvest Gold’ is highly resistant to all major crabapple diseases.
’Professor Sprenger’ - This wonderful cultivar, introduced in 1950 by Mr. S. G. A. Doorenbos
of the Hague, Netherlands, is still struggling for acceptance in this country. The tree grows to
heights of 20 to 25 ft and develops a spreading, global shape with maturity. Abundant,
showy white flowers are produced in spring followed by eye-catching 1/2 to 5/8 in orange-red
fruit in late summer. Because birds shun the fruit, these colorful ornaments are allowed to
remain on trees until midwinter. Some have found the dried fruit make interesting additions to
floral displays. ’Professor Sprenger’ is highly disease resistant.
There is no shortage of desirable crabapples for midwestern landscapes. Some like ’Bob
White’, ’Indian Magic’, ’Profusion’, ’Sentinel’, and ’Snowdrift’ have been around for years,
while newcomers ’Adirondack’, ’Doubloons’, and ’Louisa’ show promise for the future. It is
time for responsible growers and retailers to introduce superior cultivars and varieties to
homeowners, landscape architects and designers, and other grounds maintenance personnel
throughout our region.
The International Ornamental Crabapple Society has been formed to bring together breeders,
wholesalers, retailers, horticulturists, scientists, and hobbyists who are interested in
crabapples with the intent to educate the public and eliminate substandard plant material from
the market place. Persons wishing to join IOCS may contact Dr. Thomas Green, Research
Plant Pathologist, The Morton Arboretum, Lisle, Illinois 60532.

100

Table 48.

National Crabapple Evaluation Program/Fall 1990 Evaluation
Cultivar/Var.
'Adams'

b.

'Jackii'

'Beverly'
'Bob White'
'Candied Apple'
'Centurion'
'Xmas Holly'
'David'
'Dolgo'

Rep

Aes

Scab

FB

CAR PM

FE

1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2

1
2
1
2
3
3
4
3
3
2
1
2
1
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0

X-

X-

X-

X-

X-

X-

X-

X-

X-

2
2
3
3
2
2
3
3

*

0
0
0
0
0
0
0
0
0
0
0
0
0
0

Fruit
Abund.
3
3
3
2
3
1
2
2
2
4
4
4
4
5

%
Drop
5%
10%
5%
0%
0%
0%
10%
5%
0%
0%
5%
0%
0%
0%

X-

X-

X-

X-

X-

X-

X-

X*

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X*

X-

X-

0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0

0
0
0
1
0
0
2
2

4
4
3
1
2
2
3
3

0%
0%
0%
0%
0%
0%
90%
90%

101

Cultivar/Var.
'Donald Wyman'

floribunda

'Harvest Gold'
'Henningi'
'Hopa'

hupehensis

'Indian Magic'
'Indian Summer'
'Jewelberry'

Rep

Aes

Scab

FB

CAR PM

FE

3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2

3
1
2
X3
3
2
2
1
2
2
2
2
4
4
4
3
3
2
2
2
2
X*
*
3
3

0
0
0

0
0
0
*
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
XX*
0
0

0
0
0

2
0
0
*
0
0
0
0
0
0
0
0
0
0
0
2
1
1
0
2
2
2
XXX0
0

*

0
0
0
0
0
0
0
0
0
4
4
2
0
0
0
0
1
1
*
*
*
0
0

102

*

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
*
*
*
0
0

0
0
0
X*
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
X*
X*
0
0

Fruit
Abund.
3
4
3
X4
4
4
2
2
2
4
3
4
3
3
4
2
4
4
3
2
3
XXX3
2

%
Drop
95%
0%
0%
X0%
0%
0%
0%
0%
0%
5%
0%
0%
30%
50%
50%
0%
0%
0%
5%
0%
0%
XXX0%
0%

Cultivar/Var.
'Liset'
'Mary Potter'
'Molten Lava'
'Ormiston Roy'
'
'Pink Spires'
'Prairifire'
'Prof. Sprenger'
'Profusion'
'Radiant'

Rep

Aes

Scab

FB

CAR PM

FE

3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1

3
3

0
0

0
0

0
0

0
0

0
1

Fruit
%
Abund. Drop
2
0%
3
0%

X*

X*

X-

X-

X-

X-

X-

X-

3
3
3
3
2
3
2
3
2

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

2
4
3
3
4
3
4
4
3

0%
0%
0%
0%
0%
0%
0%
0%
0%

X-

X-

X-

X-

X-

X-

X-

4
4
4

0
0
0

0
0
0

0
0
0

0
0
0

3
3
3

3
3
2

20%
5%
5%

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X-

X*

X-

X-

X-

X-

X-

X-

X-

X-

2
1
2
1
2
2
4
4

0
0
0
0
0
0
4
3

0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0

1
1
1
2
0
0
0
0

4
5
4
4
3
4
2
2

5%
0%
0%
0%
5%
0%
10%
30%

2

103

Cultivar/Var.
'Ralph Shay'
'Red Baron'
'Red Jade'
'Red Jewel'
'Red Splendor'
'Robinson'
'Royalty'
'Ruby Luster'

sargentii

0
2
0
2
0
2

Fruit
Abund.
2
4
4
4
3
2

%
Drop
40%
20%
5%
10%
0%
0%

X-

X-

X-

X-

0
0

0
0

0
1

0%
0%

x-x-

x-x-

x-x-

x-x-

x-x-

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
1
2
3
3
0
0
2
3
0
0
0
0
0
0

2
2
2
3
3
3
2
3
3
2
1
1
0
1
0
1
3

0%
0%
0%
0%
5%
10%
0%
0%
25%
50%
50%
50%
0%
0%
0%
0%
0%

Rep

Aes

Scab

FB

CAR PM

FE

3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2

4
2
1
3
2
3
*
4
3'

4
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
0

X-

X-

0
0

0
0
0
0
0
0
*
0
0

x-x-

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

X-X-

3
2
3
3
3
3
4
2
1
3
4
3
3
3
3
5
4

0
0
**
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0

104

Cultivar/Var.
'Selkirk'
'Sentinel'
'Silver Moon'
'Snowdrift'
'Sberry Parfait'
'Sugar Tyme'

tschonoskii

'Velvet Pillar'
'White Angel'

Rep
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2

Aes

Scab

FB

CAR PM

FE

Fruit
%
Abund. Drop

X-X-

X-X-

x-x-

x-x-

x-x-

x-x-

X-X-

X-X-

3
4
4
1
2
*
4
*
3

0
0
0
0
0

0
0
0
0
0

0
0
0
0
0

0
0
0
0
0

0
1
3
0
0

2
2
2
2
4

50%
50%
50%
0%
0%

X-

X-

X-

X-

X-

X-

X-

0

0

0

0

1

1

0%

X-

X-

X-

X-

X-

X-

X-

0

0

0

0

0

1

0%

X-

X-

X-

X-

X-

X-

X-

X-

2
2
4
3
4
1
3
2
3

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

0
0
1
0
0
0
0
0
2

3
3
2
1
1
4
1
3
0

0%
0%
0%
0%
0%
0%
0%
5%
0%

X-X-

x-x-

x-x-

x-x-

x-x-

x-x-

X-X-

x-x-

X-X-

x-x-

x-x-

x-x-

x-x-

x-x-

x-x-

x-x-

2
2
2
3
3

0
0
0
0
0

0
0
0
0
0

0
0
0
0
0

0
0
0
0
0

0
0
0
1
0

1
0
1
2
2

0%
0%
0%
0%
5%

105

Cultivar/Var.
'White Cascade'
'Winter Gold'
y. veitchii

zum i calocarpa

0
0
0
0
0

Fruit
Abund.
4
3
4
1
3

%
Drop
5%
0%
0%
0%
0%

X-

X-

X-

X-

X-

X-

X-

X-

X-

0
0

0
0

0
0

0
0

0
0

0%
0%

x-x-

x-x-

x-x-

x-x-

x-x-

x-x-

x-x-

0
0
0

0
0
0

0
0
0

0
0
0

0
0
1

4
4
4

0%
0%
0%

Rep

Aes

Scab

FB

CAR PM

FE

3
1
2
3
1
2
3
1
2
3
1
2
3

3
4
4
3
1

0
0
0
0
0
*

0
0
0
0
0

0
0
0
0
0

0
0
0
0
0

X*

X-

X-

X-

X-

5
5

0
0

X-X-

3
1
2

X-

“■ -new plant
**=dead plant
Aes=aesthetic rating - (0-5)/0=perfect, 5=unacceptable
Scab=apple scab rating - (0-4)/0=none, 4=severe
FB=fireblight rating - (0-4)/0=none, 4=severe
CAR=cedar apple rust rating - (0-4)/0=none, 4=severe
PM=powdery mildew rating - (0-4)/0=none, 4=severe
FE=frog-eye leafspot rating - (0-4)/0=none, 4=severe
Fruit abund.=fruit abundance at rating - (0-5)/0=none/ 5=abundant
% Drop=%fruit drop at rating - (0-100%)

106

W eed Control With Landscape Fabrics
N. H. Agnevjtand J. K. lies

Introduction
Due to reported adverse effects on landscape plant growth when plastic (black or clear) Is used for
weed control, and the Increasing desire to reduce chemical use In the landscape, weed control
alternatives are needed. The ability of landscape fabrics (also referred to as geotextiles or weed
barriers) to suppress weed growth without jeopardizing the vigor of desirable landscape plants has
been well documented. Unfortunately, weeds may still cause problems when they germinate and
grow in the mulch layer covering the fabric. In the spring of 1990, a study was initiated to test the
ability of several landscape fabrics to suppress the growth of weeds in the mulch layer on top of the
fabric. Dalen Products, Inc. of Knoxville, Tennessee, provided funding and materials for this study.

Materials and Methods
The four landscape fabrics tested were:
Reemay’s Typar - stiff polypropylene/nonwoven.
Blunk’s Duon - softer polypropylene/nonwoven.
Easy Gardener’s Weedblock - punched polyethylene film.
Dalen’s Weed-X - porous polyethylene film/polyester nonwoven laminate.
Typar and Duon can be installed with either side up. Weedblock should be installed with the rough
side down. Weed-X must be installed with the smooth black side up and the nonwoven side down.
1.
2.

3.
4.
5.
6.

7.

Weed-free test plots (strips) were prepared.
Using a randomized block design, landscape fabric treatments (3 ft by 3 ft squares) were
randomly assigned to 6 test strips (replications). Each fabric appeared 3 times in each
replication.
Fabrics were covered with 1 to 1 1/2 in shredded hardwood mulch.
Seed from several species of challenge weeds were applied to the mulch covering the
fabric to augment natural weed pressure.
In August, 1990, one-half of the experiment was rated visually for weed shoot growth
occurring in the mulch.
In October, 1990, the same portion of the experiment was analyzed more thoroughly.
Root mass below the fabric and shoot growth above the fabric were rated qualitatively
and quantitatively.
The remaining plots will be evaluated in summer and fall of 1991.

107

Table 49. Subjective rating2 of weed growth occurring in the mulch layer above the various weed control
fabrics. Evaluated August, 1990.

______Observation__________

Rep 1

Rep 2

Rep 3

Fabric

1

2

3

Mean
Rating

Typar

2

3

3

2.7

Duon

3

3

2

2.7

Weedblock

4

4

5

4.3

Weed-X

1

1

1

1.0

Typar

3

2

3

2.7

Duon

4

3

3

3.3

Weedblock

4

3

3

3.3

Weed-X

1

2

2

1.7

Typar

3

3

2

2.7

Duon

3

3

2

2.7

Weedblock

4

2

3

3.0

Weed-X

1

1

1

1.0

z 1 = no weed growth, 5 = prolific weed growth.

108

Table 50. Number of shoots above the fabric. Evaluated October 1990.

Rep 1

Typar

20

19

19

19.3

Duon

25

23

17

21.7

Weedblock

24

28

62

38.0

3

2

3

2.7

Typar

25

18

23

22.0

Duon

37

30

34

33.7

Weedblock

34

22

28

28.0

1

6

12

6.3

Typar

32

25

42

33.0

Duon

22

26

27

25.0

Weedblock

25

21

28

24.7

5

2

2

3.0

Weed-X

Rep 3

Mean
Rating

1

Weed-X

Rep 2

Observation_________
2
3

Fabric

Weed-X

Overal Means
Typar

24.8

Duon

26.8

Weedblock

30.2
4.0

Weed-X

109

Table 51. Subjective rating2 of root penetration through fabric. Evaluated October, 1990.

Rep 1

Rep 2

Rep 3

3

Mean
Rating

1

2

1.0

2

2

1

1.7

Weedblock

1

1

2

1.3

Weed-X

0

0

0

0.0

Typar

1

1

1

1.0

Duon

2

1

2

1.7

Weedblock

2

1

1

1.3

Weed-X

0

0

1

0.3

Typar

1

1

1

1.0

Duon

1

2

1

1.3

Weedblock

2

0

2

1.3

Weed-X

0

0

0

0.0

Fabric

1

Typar

0

Duon

Observation
2

z 0 = no roots visible, 1 = hair roots, minor surface soil lift, 2 = some larger roots, no deep soil
disruption, 3 = larger roots, isolated deep soil lifting.

no

Table 52. Root dry weight (g) below fabric. Evaluated October 1990.

Rep 1

Rep 2

Rep 3

3

Mean
Rating

0.15

0.68

0.28

0.48

1.75

0.96

1.06

Weedblock

0.73

0.85

1.68

1.09

Weed-X

0.00

0.00

0.00

0.00

Typar

0.09

0.28

0.29

0.22

Duon

1.17

0.60

0.73

0.83

Weedblock

1.60

0.54

0.79

0.98

Weed-X

0.00

0.00

0.25

0.08

Typar

0.14

0.16

0.50

0.27

Duon

0.26

0.53

0.12

0.30

Weedblock

0.80

0.00

1.83

0.88

Weed-X

0.00

0.00

0.00

0.00

Fabric

1

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0.00

Duon

Observation
2

Overall Means
Typar

0.26

Duon

0.73

Weedblock

0.98

Weed-X

0.03

Ill

Shade and Flowering Tree Evaluation
J. K. lies
The Shade and Flowering Tree Evaluation Project is sponsored by the Iowa Nurserymen’s Research
Corporation in cooperation with the Iowa State University Department of Horticulture. Forty-two
selections of shade and ornamental trees were planted at the ISU Horticulture Research Station in
1986. Because of space constraints and poor drainage at the original site, a new evaluation site was
established just east of the turfgrass research plots in fall of 1990. Trees planted in 1990 include:
Acer negundo ’Sensation’ (Sensation Box Elder) - Three trees were originally planted and all failed to
survive the winter of 1990-91.
Acer platanoides ’Lamis’ (Crystal Norway Maple) - A Bailey Nursery selection made in Oregon by Max
Lamis. This maple is expected to grow 50 to 60 ft tall and is noted for its vigorous, straight trunk. It
reportedly has better branching than ’Emerald Lustre’ with a lighter colored leaf tip. Of the three
planted, one failed to survive the winter.
J. Frank Schmidt Nursery in Boring, Oregon, has introduced two new maples that are hybrids of Acer
truncatum (Shantung Maple) and Acer platanoides (Norway Maple). According to Schmidt, both trees
will mature at a size slightly smaller than a typical Norway maple, have a finer textured branching
habit, and leaves will exhibit shades of orange and red in fall. These new introductions are described
below.
Acer truncatum X platanoides ’Keithsform’ (Norwegian Sunset Maple) - An upright oval tree growing 35
ft tall and 25 ft wide with excellent orange-red fall color. Norwegian Sunset has a particularly nice
branch structure and uniform canopy. The trademark name, Norwegian Sunset, reflects the tree’s
similarity to Norway Maple in growth rate, branch structure, and leaf shape. All test trees survived the
first winter.
Acer truncatum X platanoides Warrenred’ (Pacific Sunset Maple) - This upright, spreading tree will
grow 30 ft tall, spread 25 ft, and displays outstanding glossy summer foliage that changes to bright
red in fall. Pacific Sunset colors earlier and a little brighter than Norwegian Sunset. Branch structure
is a little finer textured and more spreading than Norwegian Sunset. All test trees survived the first
winter.
Crataegus viridis ’Winter King’ (Winter King Hawthorn) - Is this ornamental tree truly hardy for Iowa?
After receiving conflicting reports, this tree was included in the trial for closer observation. ’Winter
King’ has white spring flowers, attractive silver bark, showy and persistent red fruit, and is virtually
thornless. All test plants survived their first Iowa winter.
Fraxinus pennsylvanica ’Mahle’ (Mahle Green Ash) - This selection comes from a tree in K. A. Mahle’s
yard in Woodbury, Minnesota. Expected to grow 50 to 60 ft tall, ’Mahle’ branches exceptionally well
as a young tree, forming a broad, oval head at maturity. Foliage is described as a good, glossy
green, and the tree is seedless. All test trees survived the winter.
Tilia americana ’Fastigiata’ (Pyramidal American Linden) - A Bailey Nurseries selection expected to
grow to 60 ft. The tree has a narrow, pyramidal form with fragrant yellow flowers. A good candidate
for street tree duty. All test trees survived the winter.
Selections added to the trial in 1991 include the following:
Acer X freemanii ’Autumn Blaze’ (Autumn Blaze Maple) - A hybrid of red maple (Acer rubrum) and

112

silver maple (Acer saccharinum) that grows approximately 50 ft tall and 40 ft wide. The tree has a
dense, oval head with ascending branches. Summer foliage is a rich green, changing to orange-red
in fall. The tree is thought to be more drought tolerant than cultivars of Acer rubrum. Selected by
Glenn Jeffers, Fostoria, Ohio, in the late 1960s.
Acer platanoides ’Oregon Pride’ (Oregon Pride Nonway Maple) - An interesting, cut-leaf form of Norway
Maple with a gold-bronze fall color. Developing a heavy crown and possessing a rapid growth rate,
’Oregon Pride’ will attain heights of 40 to 50 ft.
Acer saccharum ’Majesty’ (Flax Mill Majesty Sugar Maple) - This cultivar was originally found at Flax
Mill Nursery in Cambridge, New York. ’Majesty’ is characterized by a perfectly symmetrical, ovoid­
shaped head, numerous branches (2 to 3 times the branch number of the species), and a rapid
growth rate. Thick, dark green leaves turn orange-red in fall. Trees will grow to heights of 50 to 75 ft
and are reportedly free from sunscald and frost-crack injury.
Cornus kousa (Kousa Dogwood) - A handsome small specimen tree growing to heights of
approximately 20 ft, with an equal or greater spread. Flowers, with their showy, creamy-white bracts,
form in early to mid-June. When young, the tree has a vase-shaped growth habit, becoming rounded
with a distinct stratified branching pattern as it ages. Leaves are dark green in summer, changing to
reddish purple or scarlet in fall. Kousa Dogwood may survive winters in central Iowa, but will it flower
dependably?
Corylus colurna (Turkish Filbert) - A broadly pyramidal tree with an excellent formal character growing
40 to 50 ft in height with a spread of 20 to 30 ft. Turkish Filbert reportedly will thrive in areas with hot
summers and cold winters and is pH adaptable. Leaves are dark green in summer, turning yellow or
purple in fall. Insect and disease problems are rare.
Fraxinus pennsylvanica 'Dakota Centennial’ (Dakota Centennial Green Ash) - A globe-shaped, seedless
selection of green ash from North Dakota State University growing 40 to 50 ft in height. The tree
develops a strong central leader and desirable scaffold branches. Leaves are a glossy, dark green,
turning yellow in fall.
Fraxinus pennsylvanica ’Prairie Spire’ (Prairie Spire Green Ash) - Another hardy, seedless, green ash
from North Dakota State University. The tree is compact and columnar when young, becoming narrow
pyramidal to elliptical with age, and attaining heights of 50 to 60 ft. Bright golden yellow fall color has
been reported.
Tilia cordata ’Ronald’ (Norlin Linden) - A broadly pyramidal selection of littleleaf linden growing 35 to
45 ft tall. Norlin has a rapid growth rate, strong branches, and is more resistant to sunscald. Dark
greenish-brown stems accent the dark green summer foliage.
Tilia cordata ’Baileyi’ (Shamrock Linden) - Selected and introduced by Bailey Nurseries, this littleleaf
linden cultivar is similar to ’Greenspire’, but has stouter branching and a more open canopy.
Shamrock will grow 40 to 50 ft tall and take on a broad, conical form.

113

NCR-10 Regional Alternative Grass Trial
N. E. Christians and R. W. Moore

The North Central Region-10 (NCR-10) Regional Research Turfgrass Committee established an
alternative grass trial in the fall of 1988 at nine cooperating universities in the midwest. The objective
of this study is to evaluate the adaptation of 16 grasses that are presently not used as turf species in
the region (Table 53).
The grasses were established in a strip-split plot arrangement at the nine state sites in 3 ft by 10 ft
plots in three replications. The plots are further divided into three mowing height strips; no mow, 2 in,
and 4 in. Fertilizer was applied at a rate of 2 lb P205 and 1 lb N/1000 ft2 at establishment. No weed
control other than hand weeding was used in the first year and no additional fertilizer was applied.
Data collection sheets were distributed to each of the states in 1990 and visual quality ratings based
on a scale of 9 to 1 with 9 = best quality and 1 = dead turf, were performed monthly. The data were
sent to Iowa State University for analysis in the late fall of 1990.
All but one of the nine states submitted data, and not every state submitted data for all months.
Means of the data submitted were calculated for each state and an analysis of variance was
conducted on the 1990 means.
Sheep fescue received the highest average rating for all state locations and all three mowing heights
(Table 54). It was followed in order by Alta tall fescue, Reton red top, and Exeter colonial bentgrass.
Quality ratings for the 16 grasses are listed by state in Table 55 and by state and mowing height in
Table 56. The buffalograsses survived the winter of 1988 in four of the eight states (these grasses
were reestablished in the spring of 1990). Of the two reestablished Buffalograsses, Texoka has shown
marked improvement in its’ quality ratings over the 1989 data.
Ruff-crested wheatgrass continues to show considerable damage or complete loss at several
locations.
Poa
alpinademonstrated a lower overall rating in 1990 as compared to the 1989 data.
This trial will continue for one or two more years at which time all data will be summarized for
publication.

m

Table 53. Turfgrasses and seeding rates evaluated in the NCR-10 Regional
Alternative Turfgrass Species Trial established in the fall of 1989.
Seeding rate
lb seed/M

Common name

Scientific name

Fairway Crested Wheatgrass

Agropyron

desertorum

'Fairway'

4.3

Emphraim Crested Wheatgrass

Agropyron

desertorum

'Emphraim'

4.2

Sodar Streambank Wheatgrass

Agropyron

riparium

Ruff Crested Wheatgrass

Agropyron

desertorum

Reubens Canada Bluegrass

Poa

Durar Hard Fescue

F e s t u c a o v i n a var.

Covar Sheep Fescue

Festuca ovina

Alta Tall Fescue

Festuca arundinacea

Sheep Fescue

Festuca ovina

4.2

Bulbous Bluegrass

Poa

4.2

Alpine Bluegrass

Poa alpina

Reton Red Top

Agrostis alba

'Reton'

4.0

Colt Rough-stalked Bluegrass

Poa

'Colt'

4.0

Exeter Colonial Bentgrass

Agrostis

Texoka Buffalograss

Buchloe dactyloides

'Texoka'

plugs^

NE 84-315 Buffalograss

Buchloe dactyloides

'NE-84-315'

plugs-*-

compressa

'Sodar'

4.2

' Ruff'

6.2

'Reubens'
duriuscula

4.3
'Durur'

'Covar'
'Alta'

bulbosa

trivialis

4.5
4.5

4.0

tenuis

'Exeter'

Ipiots were established with four 2 -inch plugs per plot.

115

4.2

3.8

Table 54. Quality means of data submitted by the eight states for the 16
grasses. The grass species are listed from best to worst.
Quality
rating

Species
Sheep Fescue

5.0

Alta Tall Fescue

4.9

Reton Red Top

4.6

Exeter Colonial Bentgrass

4.6

Durar Hard Fescue

4.4

Reubens Canada Bluegrass

3.7

Cover Sheep Fescue

3.6

Fairway Crested Wheatgrass

2.9

Colt P o a t r i v i a l i s

2.6

Sodar Streambank Wheatgrass

2 .6

Ephraim Crested Wheat

2.4

Texoka Buffalograss

2.3

Bulbous Bluegrass

2 .0

Poa Alpina

1.9

Ruff Crested Wheatgrass

1.9

NE 84-315 Buffalograss

1.8

LSD

0.9

0.05

116

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Selective Control of Quackgrass With Primisulfuron
D. L. Struyk and N. E. Christians
Primisulfuron is an herbicide used to control quackgrass in corn. The objective of these studies was to
determine if primisulfuron, which will be known as ’ACE’ in the turf market, can be used as a selective
control of quackgrass in Kentucky bluegrass and perennial ryegrass. The effectiveness of two surfactants
was also evaluated.
The first study was a field investigation consisting of five treatments and a control. The treatments were
20g ai/ha, 40g ai/ha, 60g ai/ha, 20g ai/ha + 20g ai/ha at a one-week interval, and 20g ai/ha + 20g ai/ha
at a two week interval. All treatments used X-77 (0.25% v/v) as the surfactant. These were applied to a
turf area with a high population of quackgrass. This trial was initiated on August 8,1990, and an identical
separate trial begun on October 6.
Three greenhouse studies were conducted during the winter. Greenhouse Study 1 (GH 1) involved
individual pots of ’Ram I’ Kentucky bluegrass and quackgrass. The pots were treated with 20, 40, 60, and
80g ai/ha. This trial also compared two surfactants, X-77 and Sunit (an experimental surfactant from CIBAGEIGY that later had its name changed to ’Scoil’). Data was collected after 12 weeks (Figs. 14 and 15).
Greenhouse Study 2 involved the same surfactants and treatments as GH 1, but included perennial
ryegrass. The results of Greenhouse Study 2 are shown in Figs. 16 and 17. Greenhouse Study 3
involved individual pots of ’Ram I’ and quackgrass treated with 20, 40, 60, 80, 100, 120, 140, and 160g
ai/ha. All treatments used Scoil (formerly called Sunit) at 0.25% v/v. This trial was conducted to
determine the single application tolerance of Kentucky bluegrass. Data was not available at the time this
report was prepared.
The data obtained from the completed trials showed that primisulfuron will kill quackgrass and will not
detrimentally effect Kentucky bluegrass or perennial ryegrass. (It should be noted that some initial
stunting was observed on perennial ryegrass and some reduction of growth was observed at the highest
rates of treatment.) Surfactants are important to the effectiveness of this compound, but no significant
differences were observed between X-77 and Scoil (Sunit).
More work is planned on this subject during the summer and fall of 1991. There are still many questions
to be answered on the effects of primisulfuron on other grass species as well as on different cultivars of
the grasses already studied. Evaluation of the effects of primisulfuron on non-target species such as trees
and shrubs must also be made before it can be labeled for the turf market.

119

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1990 BEDDING PLANT FIELD TRIAL
Nancy H. Agnew
INTRODUCTION:
A bedding plant field trial was developed in 1990 to evaluate the garden performance of various
bedding plant cultivars under central Iowa growing conditions. The trial was planted May 17 1990.
Plants were maintained under standard garden conditions. Phosphorus (P) and potassium (K) fertility
were determined by soil tests and P and K were added prior to planting. Two maintenance nitrogen
fertilizer applications were made at the rate of 1 lb actual N/1000 ft2 of garden area. Routine manual
weed control and faded flower removal were employed to keep the plants and plantings in top
condition. Irrigation and/or rainfall of at least 1 in per week was applied to the plantings.
DATA:
Monthly performance ratings were scored on the 20th of each month from June to September.
Performance was scored on a scale of 1 to 5: 1 = poor, 2 = fair, 3 = good, 4 = very good, and 5 =
excellent. Season-average performance was the mathematical mean of the June through September
scores. Performance evaluations were based on observations of plant vigor, habit, disease resistance,
and amount and consistency of bloom. Weather tolerance was scored using the same scale as
performance ratings. Throughout the season, plants were observed for tolerance to wind and rain. A
single score was used for the season. Heat tolerance also was scored using the 1 to 5 rating scale.
Throughout the season, plants were observed for tolerance to high temperatures. A single score was
used for the season. Plant height and spread and flower size were recorded at the end of the growing
season. These measurements were recorded with the September performance rating.
PERFORMANCE REVIEW BY SPECIES:
CATHARANTHUS (annual vinca)
The best season performance among vinca groups was recorded for the Little series. A high scoring
cultivar was Morning Mist. Many of the other cultivars scored in the very good to excellent category.
They were: ’Coolers’, ’Parasol’ (1991 All-America Selections Winner), and ’Polka Dot’. The Pretty In
series did not score as well because they were not as vigorous and had a more upright and open habit
than the other vincas. Two 1991 All-America Selections winners come from this series (’Pretty in Pink’
and ’Pretty in Rose’). ’Pretty in Pink’ contains none of the purple to violet undertones that all the other
vinca varieties display. The Carpet series again performed best late in the season with ’Snow Carpet’
scoring exceptionally well for the season. The Carpets differ from most vincas because of their ground
hugging habit (6 to 8") and their adaptability to hanging baskets. The Sahara Madness series did not
perform as well but scores remained in the good to very good category. Scores were lower because
they tended to start slowly in the garden. This series has a compact and well-branched habit.
MARIGOLD (dwarf french)
The high-scoring marigold series were Laguna, Spice, and Boy. The Laguna series scored high last
season also. The large, flat flowers, similar to the Sophia flower, form are long lasting and create a
continuous carpet of color all season. We teamed ’Laguna Gold’ with ’Geranium Orbit Red’ in the ISU
Horticulture Garden to create an impressive display. The Spice series flowers are similar to the
Lagunas, but with a slightly smaller flower size. The Boy series scored well and represents the industry
standard for dwarf french marigolds with a “pompon type“ flower form.Summer 1990 was a good year for
marigolds. Moderate temperatures and abundant rainfall resulted in performance ratings of no less than
good for all cultivars tested.

124

PELARGONIUM (geraniums from seed)
The Orbit series scored highest among all groups of geranium cultivars. Specific cultivars 'Orbit
Cardinal’, 'Orbit Cherry’, 'Orbit Appleblossom’, 'Orbit Scarlet’, and Orbit Hotpink scored the highest
among all cultivars. Very good color, flower presentation, and weather resistance characterized this
group of geraniums. 'Gerónimo' a single introduction from Sluis and Groot also scored very high.
'Orange Appeal’, an intense true orange geranium, is a breakthrough color geranium from Goldsmith.
The color is indeed eye-catching, but the performance was not as good as other geraniums. We would
like to reserve judgement until it has been trialed for 2 to 3 years. The Multibloom series performed
similar to last year with early flowering and very good early garden performance. Unfortunately, it tends
to decline late in the summer.
GRANDIFLORA PETUNIA
Summer 1990 was not a great year for petunias. Cool, damp weather is not optimal for petunias that
thrive in warm temperatures and well-drained soils. The Supermagic Series scored highest for the
season with 'Supermagic Pink’ and 'Supermagic Lilac’. Both of these plants were noted as good
performers last year when temperatures were warm and drought conditions prevailed. Other notables
include the Laser and Dreams series which were included in the trial for the first time this year and
scored in the good to very good range. The Supercascade series scored second in the series season
scores along with the Frost series. Supercascade was noted last year as a good performing group.
MULTIFLORA PETUNIA
The multiflora petunias are valued for their profuse flower numbers and well-branched, compact habit
that stays compact in warm weather. The Carpet and Madness series performed equally as well in the
1990 trials, both displaying characteristics typical of the multiflora hybrids. The Madness series had
more cultivars scoring high individually with Red, Orchid, Rose, Silver, and Simply Madness scoring very
well. The new Primetime series also scored well with Primetime Coral, Plum, and Rose scoring very well.
The Polo and the Pearl series scored in the good to very good range; but not as high as the others.
Flower production and habit were good, but flower size was smaller so the color and floral display of
these series was not as impressive.

125

Top Five Series for Each Species

Catharanthus
(annual vinca)

Mariqold
(dwarf french)

Pelargonium
(seed geranium)

1.
2.
3.
4.
5.

1.
2.
3.
4.
5.

1.
2.
3.
4.
5.

Little Series (4.2)
Cooler Series (4.0)
Pretty in. Series (3.8)
Carpet Series (3.4)
Sahara Madness (3.3)

Laguna Series (4.4)
Spice Series (4.4)
Boy Series (4.2)
Sophia Series (4.1)
Marietta Series (3.9)

Petunia
(grandiflora)

Petunia
(multiflora)

1.
2.
3.
4.
5.

1.
2.
3.
4.
5.

Supermagic (3.8)
Supercascade (3.5)
Frost (3.5)
Falcon (3.4)
Laser (3.4)

Orbit Series (4.0)
Elite Series (3.4)
Pinto Series (3.3)
Multibloom Series(3.2)
Ringo Series (2.9)

Carpet (3.5)
Madness (3.5)
Primetime (3.3)
Celebrity (3.2)
Polo (3.1)

What’s New in the 1991 Bedding Plant Field Trial?
SALVIA Thirty-three cultivars of Salvia splendens have been added to the trial this year. Many new
introductions in recent years warrant the addition of this species. New shades of the traditional scarlet
sage have been introduced and these colors include: violet, salmon, purple, white, rose, and burgundy.
Three cultivars of Salvia farinácea have also been added. These varieties of mealycup sage are excellent
performers. We have added them to demonstrate their usefulness.
NICOTIANA A new group of flowering tobacco has been introduced by the Ball Seed Company. It is
called the Starship series. We’ve added it to the trial and will compare it with the Nicki series. Flowering
tobacco is a useful addition to other annuals used for bedding display and it is as easy as petunia to
grow.
IMPATIENS We have been able to add a shading structure thanks to a grant from the Society of Iowa
Florists and Growers Liaison Committee. All the major impatiens series are represented in this trial.
NEW GUINEA IMPATIENS New Guinea Impatiens grow more popular with consumers every year. We
have added a field trial that includes all the major commercial series in addition to some new commercial
series and ISU’s Cyclone series.

126

Cultivars With a Season Performance Score of 4.00 or More
Table 57.
Catharanthus
(annual vinca)

Marigold
(dwarf french)

Pelarqonium
(seed geranium)

Little Bright Eye (4.3)
Little Linda (4.3)
Little Pinkie (4.3)
Morning Mist (4.3)
Pretty in Pink (4.3)
Snow Carpet (4.0)
Grape Cooler (4.0)
Peppermint Cooler (4.0)
Little Blanche (4.0)
Little Delicata (4.0)
Parasol (4.0)
Polka Dot (4.0)

Sophia Orange (5.0)
Bonanza Deep Orange (4.5)
Orange Boy (4.5)
Yellow Boy (4.5)
Laguna Gold (4.5)
Laguna Yellow (4.5)
Yellow Marietta (4.5)
Spice Saffron (4.5)
Harmony Boy (4.3)
Laguna Orange (4.3)
Spice Ginger (4.3)
Spice Orange (4.3)
Regular Sophia (4.3)
Golden Boy (4.0)
Disco Marietta (4.0)
Orange Jacket (4.0)
Janie Harmony (4.0)
Legend Yellow (4.0)
Early Queen Sophia (4.0)
Calico Yellow (4.0)
Gold Supreme Nugget (4.0)

Cardinal Orbit (5.0)
Cherry Orbit (5.0)
Scarlet Orbit (4.8)
Appleblossom Orbit (4.8)
Hotpink Orbit (4.5)
Orchid Orbit (4.3)
Pink Orbit (4.3)
Red Orbit (4.3)
Pink Elite (4.0)
Rose Orbit (4.0)
Deep Salmon Orbit (4.0)
Scarlet Eyed Orbit (4.0)
Light Salmon Orbit (4.0)

Petunia
(grandiflora)
Falcon Rose (4.5)
Falcon Salmon (4.5)
Laser Blue (4.5)
Supermagic Pink (4.5)
Ultra Salmon (4.5)
Salmon Cloud (4.3)
Salmon Dreams (4.3)
Falcon Mid Blue (4.3)
Falcon Rose and White (4.3)
Falcon White (4.3)
Supercascade Lilac (4.3)
Ultra White (4.3)
Sugar Daddy (4.0)
Pink Dreams (4.0)
Laser Lavender (4.0)
Picotee Rose (4.0)
Supermagic Orange (4.0)

127

Petunia
(multiflora)
Red Madness (4.5)
Celeb Strawberry Ice (4.3)
Orchid Madness (4.3)
Rose Madness (4.3)
Silver Madness (4.3)
Simply Madness (4.3)
Plum Madness (4.0)
Sheer Madness (4.0)
Primetime Coral (4.0)
Primetime Plum (4.0)
Primetime Rose (4.0)

O rn a m e n ta l G ra s s S tu d ie s-1 9 9 0
R. G. Roe and N. E. Christians

This study is being conducted on the Turfgrass Research Plots at the Iowa State University
Horticulture Research Station near Ames, Iowa. This study was started in 1989. The purpose of the
study is to investigate the suitability of nineteen species of ornamental grass for the Iowa climate (Fig.
18 & 19). It is expected that the trial will run for 5 to 8 years.
The area chosen for the study is on the west side of the turfgrass maintenance building. Individual
plots measured 4 ft by 5 ft, for a total of 68 plots, in a bow-shaped bed measuring 270 ft by 5 ft (Fig.
18). The grasses were planted with the tallest, giant Chinese silver grass
floridulus
’Giganteus’) in the center. The remaining grasses were placed in descending size order, with the 2
plants of each cultivar being planted on the right and left of the center grass. Each plot is of sufficient
size to allow adequate growth of the grasses, and to enable them to grow without competition. A total
of 34 cultivars or varieties, 2 plants each, were planted in mid-September of 1989. Several plants did
not survive the first winter, possibly due to the late planting date-these were replaced the spring of
1990. The grass plants were supplied at a substantial discount by the Kurt Blumel Nursery in
Maryland, which is one of the premier ornamental grass nurseries in the United States.
Larger plots measuring approximately 4 ft by 12 ft, for a total of 12 plots, contain an additional 14
varieties (Fig. 19). These grass plants were in the 1989 container overwintering trial. The grasses
were started from seed in the greenhouse, potted into 4" pots in June, and allowed to develop in the
greenhouse. They were potted into 1 gal containers in July and moved to shade at the Horticulture
Research Station to harden prior to being placed on nursery beds under irrigation in August. The
pots were moved to the over wintering area and covered in October prior to a killing frost. The
grasses received irrigation and were sprayed with a fungicide. Rodenticide pellets were placed
among the grasses prior to covering with plastic, straw, and a top sheet of plastic. The grasses were
uncovered in April when it was considered unlikely that a severe cold spell would return. They were
planted into the beds in May, 1990.
After two winters the following grasses exhibit adaptability to Iowa:
Common Name
Big blue stem
Blue fescue
Blue wild rye grass
Bottle brush grass
Canada wild rye
Feather grass
Feather reed grass
Giant blue wild rye grass
Giant Chinese silver grass
Giant feather grass
Golden variegated ribbon grass
Hairy mellic
Japanese silver grass
Japanese silver grass
June grass
Karl foerster’s feather reed grass
Late blooming tufted hair grass
Little blue stem

Botanical Name
Andropogon
gerardii
Festuca ovina ’Glauca’
Elymus glaucus
Hystrix patula
Elymus canadensis
Stipa capillata
Calamagrostis acutlflora strlcta
Elymus giganteus ’Vahl Glaucus
Miscanthus floridulus ’Giganteus’
Stipa gigantea
Phalaris arundinacea luteo-picta
Melica ciliata
Miscanthus sinensis ’November Siberfeder
Miscanthus siensis ’November Sunset’
Koeleria cristata
Calamagrostis arundinacea ’Karl Foerster’
Deschampsia caespitosa tardiflora
Andropogon scoparius

128

Mosquito grass
Prairie dropseed
Purple moor grass
Purple moor grass
Quaking grass
Red switch grass
Red switch grass
Red switch grass
Sand hills big blue stem
Scottish tufted hair grass
Sideoats grama
Small Japanese silver grass
Switch grass
Tall purple moor grass
Tall purple moor grass
Tall purple moor grass
Tall purple moor grass
Tall purple moor grass
Tall purple moor grass
Tufted hair grass
Tufted hair grass
Tufted hair grass
Tufted hair grass
Variegated maiden grass
Viviparous hair grass

Boutelous gracilis
Sporobolus heterolepis
Molinia caerulea
Molinia caerulea ’Moorhexe’
Briza media
Panicum virgatum ’Haense Herms
Panicum virgatum ’Rehbrun’
Panicum virgatum
Andropogon hallii
Deschampsia caesp/fosa’Schottland’
Bouteloua curtipendula
Miscanthus oligostachys
Panicum virgatum
Molinia caerulea sp arundianacea ’Sky Race’
Molinia caerulea sp arundinacea ’Bergfreund’
Molinia caerulea sp arundinacea ’Transparent’
Molinia caerulea sp stlmfomsvrs ’Windspiel’
Molinia caerulea sp arundinacea
Molinia caerulea sp arundinacea ’Staefa’
Deschampsia caespitosa ’Bronzeschleier’
Deschampsia caespitosa ’Goldgehaenge’
Deschampsia caespitosa ’Tautraeger’
Deschampsia ’Goldstaub’
Miscanthus sinensis ’Morning Light’
Deschampsia vivipara

The following grasses were less adaptable, exhibiting poor growth and some winter kill:
Giant feather grass
Japanese silver grass
Scottish tufted hair grass
Tufted hair grass
Tufted hair grass
Tufted hair grass
Variegated maiden grass

Stipa gigantea
Miscanthus sinensis ’November Sunset’
Deschampsia caespitosa ’Schottland’
Deschampsia caespitosa ’Goldgehaenge’
Deschampsia caespitosa ’Tautraeger’
Deschampsia ’Goldstaub’
Iscanthus sinensis ’Morning light’

The following grasses suffered winter kill:
Hairy mellic
Japanese silver grass
Northern seat oats

Melica ciliata
Miscanthus sinensis
Chasmanthium latifolium

129

i

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Figure 18

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ORNAMENTAL GRASS TRIALS

ft 7-b

No.

ft

36

ft

4- 6

Botanical Name

Common Name

1

Deschampsia vivipara
Briza media
Festuca ovina 'Glauca'
Sporobolus heterolepis
Bouteloua gracilis
Melica ciliata
Koeleria cristata
Bouteloua curtipendula
Panicum virgatum
Elymus canadensis
Andropogon gerardi
Andropogon hallii
Andropogon scoparius
Hystrix patula
Panicum virgatum

Viviparous Hair Grass
Quaking Grass
Blue Fescue
Prairie Dropseed
Mosquito Grass
Hairy Mellic
June Grass
Sideoats Grama
6
Switch Grass
7
Canada Wild Rye
8
Big Blue Stem
9 ' Sand Hills Big Blue Stem
Little. Blue Stem
10
Bottle Brush Grass
11
12
Switch Grass

2A
2B
3A
3B
4A
4B
5

131

Environmental Research

Several of our more in-depth research projects involving graduate research assistants are aimed at
environmental issues. These projects generally require 2 to 4 years to complete and reports on the
progress of these projects are usually not included in the annual report.
Beginning this year, brief descriptions of these projects will be included. These descriptions concern work
in progress. Full reports on the work will become available as the projects are completed.

Non-Target Movement of Herbicides Applied to Turfgrass Areas
H. H. Valenti, N. E. Christians, and M. D. Owen

Pesticide spray drift has been and will continue to be an important concern. The lawn care industry has been
under special scrutiny because their predominant customer base is homeowners. Most studies conducted to
investigate the effect of meteorological conditions, formulations, and application parameters on spray deposition
have dealt with agricultural sprayers. Very little research has been directed toward the evaluation of equipment
and the application parameters used in other areas such as in the lawn care industry. Therefore, research has
been undertaken to determine the efficiency under varying wind conditions of three common lawn-care spray
nozzles and to quantify the level of off-target particle movement with each. The three sprayers used were a
hydraulic sprayer with a ChemLawn gun®, a carbon-dioxide pressurized backpack sprayer with 8004 VS® nozzles,
and a hydraulic sprayer with RA-6® nozzles. The delivery rates for the three sprayers were 3.5, 0.27, and 0.54
gal/min, respectively. The operating pressure and ground speed were adjusted for each sprayer so the mean
volume rates were 120, 20, and 40 gal/a, respectively. The triethylamine salt of triclopyr [(3, 5, 6-trichloro-2pyridinyl)oxy] acetic acid was applied at a rate of 0.45 lb ai/a with the addition of 0.01% w/v Fluorescein, a
fluorescent dye.
The spray application was made along a line perpendicular to wind direction. Three sampling lines were set
perpendicular and downwind from the spray-swath edge. Sample location spacing was 1, 3, 5, and 7 ft. Two
mylar sheets mounted on poster board and two tomato plants were placed at each location. Plants were spaced
in a fan-like arrangement so that there would be no interference at each distance. Two crystallizing dishes at five
locations were used to sample within the spray swath. Between the crystallizing dish locations, 2 potted turfgrass
samples were placed. Immediately following application, plant samples, mylar sheets, and crystallizing dishes
were collected and individually stored until fluorescent analysis could be completed. One of the 2 tomato plants
at each sampling site was returned to the greenhouse for visual observations of triclopyr injury.
In 1990, the experiment was run twice during September and November and although not all the data has been
statistically analyzed, several observations were made. First, tomato plants next to the spray swath unavoidably
received direct-spray contact with the Chemlawn gun® and RA-6® nozzles. These plants showed severe herbicide
injury. Second, plants further downwind showed very little or no injury with both types of equipment. Third,
tomato plants at all four distances showed herbicide injury with the flat-fan nozzles. On both application dates
the wind speed was very low (1-3 mph), which indicates potential danger when using flat-fan nozzles.

132

Isolation and Identification of Allelopathic Compounds
D. L. Liu and N. E. Christians

Allelopathy is a term used to describe a chemical interaction among plants. It is often referred to as the
detrimental effects of higher plants of one species (the donor) on the germination, growth, or development of
plants of another (receptor) species. The detrimental effect is exerted through release of a chemical by the donor.
Several chemical groups including phenolic acids, flavonoids, quinones, terpenoids, steroids, purines, long-chain
fatty acids and acetylenes, organic acids, unsaturated lactones, and others have been classified. Although the
specific chemicals involved in allelopathy remain obscure, they have an important role in crop production and crop
protection. To determine the chemical specificity for allelopathy, identification of the causative agents is required.
Based on preliminary studies, allelopathic compounds exist in grain that inhibit the establishment of a variety of
plant species by limiting root formation during germination. It will be environmentally and economically desirable
to exploit the phenomenon of allelopathy in grain products as potential alternatives to conventional herbicides.
If the purification method of extracting the allelopathic compounds can be established, it could potentially be
marketed as a naturally-occurring, environmentally-safe-herbicide.
The purposes of the study underway at Iowa State University are to evaluate the phytotoxicity of various grain by­
products, to extract and purify the allelopathic compound(s) from the selected grain products, and to identify the
chemical structure(s) of the allelopathic compound(s).

Evaluation of Species of Pseudomonas and Streptomyces as Potential
Biocontrol Agents for Dollar Spot and Leaf Spot3
C. F. Hodges, N. Christians, and D. F. Campbell

Isolates of bacteria in the genus Pseudomonas and of actinomycetes in the genus Streptomyces are being
evaluated for their ability to control infection of grasses by the dollar spot (
homoeocarpa) and leaf
spot (Bipolaris sorokiniana) pathogens. The evaluation process will include laboratory bioassays to determine
biocontrol activity and field evaluation to determine the potential for control in the field. Preliminary laboratory
studies have established biocontrol activity against dollar spot in three isolates each of Pseudomonas and
Streptomyces. The isolates of both organisms substantially decrease the development of dollar spot infection
over a 3 day period. The average decrease in disease (measured as loss of chlorophyll and yellowing) by the
six isolates is 97.5%. The Pseudomonas species are less active in controlling leaf spot, decreasing disease by
an average of 81 %. One isolate of Streptomyces, however, has almost completely prevented leaf spot in
preliminary studies.
The studies conducted to date are preliminary and the potential control activity found in laboratory bioassays
has not been evaluated in the field. Field studies are planned for the summer of 1991 to determine the
potential use of these microbes for controlling dollar spot and leaf spot in the field.
aThis research is being supported in part with a grant from the Soil Technologies Corporation.

133

Physiological Management of Chlorosis Associated with Foliar
Pathogens of Turfgrasses3
C. F. Hodges
Research is in progress to determine the potential for manipulation of symptom expression by leaf spot
(JB i p o l a r i s s o r o k i n i a n a ) infected turfgrasses. Studies conducted over the last eight years have established that
foliar yellowing of leaves infected by leaf spot (and possibly other leaf infecting pathogens) is due to a
combination of hormonal imbalances and the production of fungal toxins during the process of infection.
Preliminary research suggests that several substances are active against the hormone-induced yellowing
during infection. These substances function by either interrupting the biosynthesis of the hormones during
infection, or by preventing the mode of action of the hormones after they are produced. Preliminary studies in
which leaf spot infection causes at least a 50% loss in chlorophyll over four days can be decreased to a 9%
loss in plants treated with one substance under study. The remaining loss of chlorophyll is believed due to a
toxin that functions independently of the hormone imbalance.
The intent of these studies is to develop a new approach to foliar disease control that would not prevent
infection, but would limit the expression of yellowing by infected leaves. With frequent mowing, the infected
tissue would be removed and the small lesions produced by the pathogen without yellowing would not
interfere with the aesthetics of the turf.
‘‘This research is being supported in part by a grant from the United States Golf Association.

Plant and Soil Response to Nitrogen Fertilizer Source
J. N. Ryan, M. L. Agnew, and N. E. Christians

Turfgrass managers have several nitrogen sources from which to choose. Quick-release sources provide fast
green-up and are relatively inexpensive. Slow-release sources extend the feeding time by slowing the release
rate of available nitrogen. Some advantages claimed from using slow-release sources are reduced chance of
fertilizer burn, less volatilization, and less leaching.
With the environmental concerns currently surrounding fertilizers and the leaching of nitrates into the
groundwater, it is important to understand the possible differences among nitrogen sources as they pertain to
nitrogen use efficiency and the movement of nitrates in the soil.
This study will evaluate 8 fertilizer sources as to their effects on plant growth and nitrogen content in plant
tissue. In addition, the movement of nitrates through the soil will be monitored. The study was initiated in the
spring of 1991 on an established turf of ’Glade’ Kentucky bluegrass mowed at two in.

134

The following is the list of treatments:

1)
2)
3)
4)
5)
6)
7)
8)
9)

CORON 28-0-0
Nutralene 40-0-0
Sulfur-Coated Urea 37-0-0
Urea 46-0-0
Ringer Lawn Restore 10-2-6
Ureaform 38-0-0
N-Sure 28-0-0
ISU Experimental 10-1.5-.5
Control - No fertilizer

Treatments will be applied at a rate equivalent to 1 lb N/1000 ft2 on four dates scheduled for May 2, June 1,
August 15, and September 15.
Measurements of plant growth will include weekly observations of visual quality, clipping yields, and
chlorophyll content. Plant development will be monitored by measuring plant density, thatch depth, thatch
organic matter content, rhizome weights, and root distribution. These measurements will be taken prior to the
first treatment, in the middle of summer, and at the end of the season.
Nitrogen content in leaf tissue will be measured weekly and nitrate content in the soil at several different
depths up to 3 ft will be taken initially, in midsummer, and at season’s end.

Allelopathic Effects of Several Terpenoids on Plant Growth
J. N. Ryan, N. E. Christians, and J. H. Dekker
Allelopathy may be defined as biochemical interactions between plants. In the past, interactions covered by
the term allelopathy have included both beneficial and deleterious effects imposed by one plant upon another
although it is more commonly used to refer to the harmful effects. The "toxins" produced by plants are
referred to as allelochemicals.
Concern about environmental pollution by pesticides has increased immensely within the past few years. The
possible use of allelochemicals as naturally-occurring herbicides of low toxicity has become more appealing to
companies responsible for producing pesticides.
This particular research project will screen naturally-produced chemical compounds starting with chemicals
from the terpenoid family. The following chemicals will be screened for allelopathic effects:
1) Borneo!

2)

Camphene3) Camphor 4) Carvo

5) Carophyllene 6) 1,8-cineole 7) Dipentene 8) Limonene
9) Linalool

10) 4-ol-terpinen11) 12-terpineol

Chemicals will be screened for phytotoxic activity on several turf and weed species using petri-dish assays
in the lab and pot experiments in the greenhouse. These initial procedures should provide some candidates
for further greenhouse study and possible field research.

135

Organic Lawn Care Trial

S. M. Kassmeyer, N.E. Christians, and M. L. Agnew
This trial was established in the summer of 1990 in Ames, Iowa, on the corner of 13th Street and Haber Road.
The objective of this study is to observe the effects of two “no pesticide* natural organic fertilizer products at
split rates, and one complete fertilizer system, using a home lawn scenario including herbicides and
insecticides. The study is being conducted under non-irrigated conditions.
The treatments included:
Scott’s Complete 4-step program
ISU Experimental - 4 lb. N /1000 ft2 applied in spring
ISU Experimental - split treatment of 2 lb N spring & 2 lb N late summer
Ringer 10-2-6 - 4 lb. N/1000 ft2 applied in spring
Ringer 10-2-6 - split treatment of 2 lb N spring & 2 lb N late summer
This study was replicated three times in a randomized, complete-block design. All plots are mowed weekly by
the University Student Housing Department maintenance personnel.

Pesticide and Fertilizer Fate in Turfgrasses Managed Under
Golf Course Conditions in the Midwestern Region
S. K. Starrett, N. E. Christians, and A. B. Blackmer

Various chemicals and nutrients are widely used by the turfgrass industry to maintain a high quality stand of
turf. Runoff and leaching of fertilizers and pesticides from golf courses, recreational, agricultural, municipal,
and industrial operations are perceived to be an important environmental problem. In this study, we are trying
to answer the following question. How much of the nitrogen, phosphorous, Trimec®, Pendimethalin,
Isazophos, Chlorpyrifos, Metalaxyl, and Chlorothalonil applied to a turf area maintained as a golf course
fairway move past the root system to the groundwater? This three-year research project is being funded by
the United State Golf Association (USGA).
For the first year of the project, the fate of nitrogen and phosphorous will be studied. The soil that was used
was excavated from the Horticulture Farm with an established stand of turf cut at fairway height. Undisturbed
soil columns were brought into the greenhouse in November, 1990, and testing started in February, 1991.
The one-week testing procedure starts with applying nitrogen and phosphorous in a liquid form to the turf.
The source of nitrogen is urea and for phosphorous, calcium phosphate was used. To distinguish between
nitrogen that is stored in the soil and nitrogen that is applied, the urea is labeled with 15N which is only
present in extremely low levels in nature.
To determine the effects of irrigation rates, two watering schemes were used.One is an application of 1 inch
immediately after nutrients are applied and the other is 4 separate quarter inch applications distributed
throughout the one week test period. Volatilizing nitrogen and any soil water that leaches through the column
is collected and tested for nutrients at the end of the test period, and the soil and vegetative materials are
dried and sent to the analytical lab for testing. The following figure is a diagram showing the method of
collecting volatilized nitrogen and soil water leachate.

136

S c h e m a tic of V o l a t i l i z i n g Nitrogen C o l le c t i o n

To Individual
Chambers

Sulfunc
Acid

*.

•%

\\

\\

•%

Flowmeter

•/•/•/•/•/•/•/•I

Flowmeter
>.« S •% • s • % • % • % - %

'•

•

>

Distilled
Vater

'A

Sulfuric
Acid

To Collect
Volatilized Nitrogen

Soil Column With
Glass Collection Chamber

137

Vacuum Pump

Introducing
Iowa State University Personnel
Affiliated with the Turfgrass Research Program

Dr.

M ichael Agnew

Associate Professor, Extension Turfgrass Specialist.
Horticulture Department.

Ms. Susan Berkenbosch

Extension Associate,
Department

Mr. Tim Bormann

Field Technician, Horticulture Department

Mr. Doug Campbell

Lab Technician, Horticulture Department

Dr. Nick Christians

Professor, Turfgrass Science.
Research and Teaching. Horticulture Department.

Mr. Robert Clause

Field Technician. Horticulture Department

Ms. Paula Flynn

Extension Associate. Plant Disease Clinic

Dr. Mark Gleason

Assistant Professor, Extension Plant Pathologist.
Plant Pathology Department.

Ms. Harlene
Valenti

H

Horticulture

Extension Associate. Weed Science Department.
Graduate Student Ph.D. (Christians/Owen).

Dr. Clinton Hodges

Professor, Turfgrass Science.
Research and Teaching. Horticulture Department.

Dr. Donald Lewis

Associate Professor, Extension Entomologist.
Entomology Department.

Ms. Dianna Liu

Graduate Student and Research Associate.
Horticulture Department PhD. (Christians).

Mr. M att Mixdorf

Field Technician. Horticulture Department

Mr. Richard Moore

Research Associate. Horticulture Department.

Mr. Glenn Pearston

Computer Consultant. Horticulture Department.

Mr. Gary Petersen

Jasper County Extension Director and Graduate Student.
Horticulture Department M.S. (Agnew, M.).

Mr. Roger Roe

Graduate Student and Research Associate.
Horticulture Department M.S. (Christians/Agnew N.)

Mr. Jeff Rosener

Horticulture undergraduate student.

Mr. Jeff Ryan

Graduate Student and Research Associate.
Horticulture Department M.S. (Christians/Agnew M.)

Mr. Jeff Schmidt

Field Technician, Horticulture Department

Ms. Marcy Simbro

Field Technician. Horticulture Department.

138

Mr. Steve Stanett

Graduate Student and Research Associate.
Horticulture Department M.S. (Christians)

We would also like to thank Mark Stoskopf, Superintendent of the Horticulture Research Station, and
Adrian Lucas, William Emley, and Lynn Schroeder for their support during the last year.

Companies and Organizations That Made Donations
or Supplied Products to
the Iowa State University Turfgrass Research Program
Special thanks are expressed to the Big Bear Turf Equipment Company and Cushman Turf for providing
a Cushman Truckster, a mataway, and a Lawn-Aire IV for use at the research area in 1989; to Tri-State
Turf and Irrigation for providing a Greensmaster III Triplex Greensmower for use on the research green;
to the Toro Company and Tri-State Turf and Irrigation for providing a Toro 84 Triplex mower.

American Hoechst Corporation
Agricultural Chemicals Department
Route 1 - Box 7
Brownsdale, Minnesota 55918

Dow / Elanco
Midland, Michigan 48674

Dupont Incorporated
1007 Market Street
Wilmington, Delaware 19898

BASF Corporation
1000 Cherry Hill Road
Parsippany, New Jersey 07054

EniChem Americas, Inc.
Research and Development Center
2000 Princeton Corporation Center
Monmouth Junction, New Jersey 08852

Big Bear Turf Equipment Company
10405 ’J’ Street
Omaha, Nebraska 68127

E-Z-Go Textron
Post Office Box 388
Augusta, Georgia 30906

Brayton Chemical Company
215 North Sumner Street
West Burlington, Iowa 52655-0437

CelPril Industries
251 Oak Street
Manteca, California 95336

Fermenta Plant Protection Company
Post Office Box 348
7528 Auburn Road
Painesville, Ohio 44077

CIBA-Geigy Corporation
Agriculture Division
Greensboro, North Carolina 27049

Grain Processing Corporation
Post Office Box 349
Muscatine, Iowa 52761

Cushman Turf
5232 Cushman
Lincoln, Nebraska 68501

Grace SIERRA
Post Office Box 4003
Milpitas, California 95035-2003

D & K Turf Products
8121 Parkview Drive
Urbandale, Iowa 50322

GrassRoots Turf
6143 Southwest 63rd
Des Moines, Iowa 50321

m

Hawkeye Chemical Company
Post Office Box 899
Clinton, Iowa 52732

NOR-AM Chemical Company
3509 Silverside Road
Post Office Box 7495
Wilmington, Delaware 19803

International Seeds
820 First Street
Post Office Box 168
Halsey, Oregon 97348

PBI/Gordon Corporation
1217 West 12th Street
Post Office Box 4090
Kansas City, Missouri 64101-9984

Iowa Golf Course Superintendents
Association
Pickseed West Incorporated
Post Office Box 888
Tangent, Oregon 97389

Iowa Professional Lawn Care
Association

Professional Turf Specialties Inc.
133 Kenyon Road
Champaign, Illinois 61820

Iowa Turf Producers and
Contractors

Rhone-Poulenc Chemical Company
Black Horse Lane
Post Office Box 125
Monmouth Junction, NJ 08852

Iowa Turfgrass Institute

Lebanon Chemical Corporation
Country Club Fertilizer Division
Post Office Box 180
Lebanon, Pennsylvania 17042

Ringer Corporation
9959 Valley View Road
Minneapolis, Minnesota 55344

LESCO Incorporated
300 South Abbe Road
Elyria, Ohio 44035

O. M. Scott and Sons
14111 Scottslawn Road
Marysville, Ohio 43041

Loft-Kellogg Seed
322 East Florida Street
Post Office Box 684
Milwaukee, Wisconsin 53201

Ross Daniels Inc
1720 Füller Road
West Des Moines, Iowa 50265

Milorganite
735 North Water Street
Milwaukee, Wisconsin 53200

Spraying Systems Company
N Avenue at Schmale Road
Wheaton, Illinois 60187

Monsanto Company
Agricultural Products Division
800 North Lindbergh Boulevard
St. Louis, Missouri 63167

Sustance Corporation
1107 Hazeltine Boulevard
Chaska, Minnesota 55318

141

Terra Chemical Corporation
Box 218
Quimby, Iowa 51049

Tri State Turf & Irrigation Co.
6125 Valley Drive
Bettendorf, Iowa 52722

The Toro Company
Irrigation Division
Riverside, California 92500

UAP Special Products
Omaha, Nebraska 68100

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'Urand justice for all
The Iowa Cooperative Extension Service’s programs and policies
are consistent with pertinent federal and state laws and regulations
on nondiscrimination regarding race, color, national origin, religion,
sex, age, and handicap.

Cooperative Extension Service, Iowa State University of Science
and Technology and the United States Department of Agriculture
cooperating. Robert M. Anderson, Jr., director, Ames, Iowa.
Distributed in furtherance of the Acts of Congress of May 8 and
June 30, 1914.