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1986
Iowa
Turfgrass
Research
Report

&

Cooperative Extension Service

E&lowa State University
Ames, Iowa 50011
FG-452 | July 1986

Introduction

The f o l l o w i n g research report is the sixth yearly publication of the
r e s u l t s of turfgrass research projects performed at Iowa State University.
The first was published for the 1981 field d a y , which was held June 18, of
that y e a r .
The others were published in conjunction with the 1982, 1983,
1984, and 1985 field d a y s .
The first cultivar and management studies at the field research area were
s e e d e d in A u g u s t 1979, and many of these investigations are now in their
seventh s e a s o n .
The area has been expanded every year and by 1983 there were
4.2 acres of irrigated and approximately 3.0 acres of non-irrigated research
area.
Funding was obtained in 1983 to add 2.7 acres of irrigated research
plots to the exiting s i t e .
This construction was completed in the spring of
1985.
Several new studies were initiated on this area in the 1985 and 1986
seasons and a map showing the location of these studies can be found in this
report.
The e x p a n s i o n w h i c h h a s t a k e n place since 1979 would not have been
possible without the cooperation of the Iowa Agriculture Experiment Station,
the Iowa Turfgrass I n s t i t u t e , the Iowa Golf Course Superintendent's Associat i o n , the Iowa Professional Lawn Care Association, and the newly formed Iowa
Turfgrass Producers and Contractors (ITPAC) organization.
We would also like to acknowledge Kenneth Diesburg, Young J o o , Michael
G a u l , Zachary R e i c h e r , Jim W a l s e r , Rob D e m u t h , Dan Weidemeir, Pat Gradoville,
M i k e N u l l , Richard M o o r e , Paul J o h n s o n , and all the others who have been
employed at the field research area in the past year for their efforts in
building the p r o g r a m .

E d i t e d by N i c k C h r i s t i a n s , associate p r o f e s s o r , turfgrass science; Michael
A g n e w , assistant p r o f e s s o r , turfgrass extension; and Gene H e t t e l , extension
communications s p e c i a l i s t .

Table of Contents

ENVIRONMENTAL DATA

1 - 2

TURFGRASS RESEARCH AREA M A P S

3 - 5

SPECIES AND CULTIVAR TRIALS
The 1985 Results of High- and Low-Maintenance Kentucky
Bluegrass Regional Cultivar Trials

6

Regional Perennial Ryegrass Cultivar Evaluation

12

Perennial Ryegrass Cultivar Evaluations

15

Fine Fescue Cultivar Trial

16

Fine Fescue Management Study

19

Tall Fescue Management Study

21

Bentgrass Management Study

24

FERTILIZER INVESTIGATIONS
Nitrogen X Potassium Study

26

Evaluation of Different Granular Nitrogen Sources for
Fertilization of Kentucky Bluegrass Turf

29

Summer Slow-Release Nitrogen Sources Comparison Study

31

Evaluation of Liquid Fertilizer Programs on Three
Kentucky Bluegrass Cultivars

33

HERBICIDE S T U D I E S
1985 Preemergence Crabgrass Control Study

36

1985 Preemergence Annual Grass Control Study

38

The Effect of Preemergence Herbicides on Root Inhibition
of Kentucky Bluegrass (Poa pratensis)

39

1985 Postemergence Annual Weed Control Study

42

1985 Broadleaf Weed Control Study

44

1985 Phytotoxicity Tests

47

1985 Poa annua Control Study

49

Rubigan Bentgrass Cultivar Study

53

GROWTH RETARDANT INVESTIGATIONS
LIMIT: Effects of a High-Concentration at Six Application
Dates on Kentucky Bluegrass

55

TURFGRASS DISEASE RESEARCH
Evaluation of Fungicides for Control of Dollar Spot
on Penneagle Bentgrass - 1985

57

Evaluation of Fungicides for Control of Dollar Spot
on Emerald Bentgrass - 1985

59

Evaluation of Fungicides for Control of Bipolaris Leaf Spot
on Park Bluegrass - 1985

61

Pythium Root Dysfunction Field Studies

62

MANAGEMENT STUDIES
Sod Reestablishment Study

64

Influence of Soil Compaction on 14 Kentucky
Bluegrass Cultivars

67

Turfgrass Cultivation Studies

68

INTRODUCING
The Iowa State University Personnel
Affiliated with the Turfgrass Research Program

COMPANIES AND ORGANIZATIONS which have made donations to the
Research Program

71

72

Environmental Data

RAINFALL 1985

—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I—I

I I—I—I

I I I

4 4 4 4 4 4 5 5 5 5 5 5 6 6 6 6 6 6 7 7 7 7 7 8 8 8 8 8 8 9 9 9 9 9 9 1
0 0 1 1 2 2 0 0 1 1 2 2 0 0 1 1 2 2 0 0 1 2 2 0 0 1 1 2 2 0 0 1
1 2 2 0
4 9 4 9 4 9 4 9 4 9 4 9 3 8 3 8 3 8 3 8 3 3 8 2 7 2 7 2 7 1 6 1 6 1 6 0
1

MONTHDflY

AMES

1

DATE
MAXIMUM E Q U A L S STAR SYMBOL
MINIMUM E Q U A L S D A S H E D LINE

A M E S - 5 DAY

AVERAGES
2

Wildflower and
Native Grass
Establishment Study

0)
to

CO
(D

ÖUO
_o
03
3
CQ

Common

National
Kentucky
Bluegrass
Trial
(Non-Irrigated)

Vantage

Fall
Fertilization
Study

Parade

Ram I

Park

Premium

Sod Blend

Baron

Tall Fescue
Control
Study

Growth Ret.
Study

Parade

Baron

P. Ryegrass
Cultivar Evaluations

Sod
Re-establishment

Tall Fescue

Park

Tall Fescue
Management
Study

Baron

Turf grass
Research
Plots

N & K Study
Phosphorus
Fertilization
Demonstration

Rugby

Sod Production Study

Non-Irrigated ¡

Tall Fescue
Control
Study

Fine
Fescue
Management
Study

Buffalograss Management Study
Texoka

Common

Tall FescueKentucky
Bluegrass
Seed Mixtures

Kentucky Bluegrass
Management Study
Non-Irrigated |

Irrigated

Parade
Perennial Ryegrass
Management Study

Perennial
Ryegrass
Cultivar
Evaluations

Kentucky
Bluegrass
Compaction
Study

Irrigated

Fine
Fescue
Cultivar
Trials

Baron

i

I—

Park
Bentgrass
Cultivar
Study
Premium
Sod
Blend

Creeping
Bentgrass
Herbicide
Trials

Sharps

Tall Fescue
Regional Trials
Enmundi

I

Penneagle

Penncross

Emerald

Fungicide
Trials

Herbicide
Trial

Fungicide
Trials

Emerald

Penneagle

Penncross

Park

Gr>iiwth
Fungicide
Trials

Retardant
Timing Study"

N
Building
Regional Kentucky
Bluegrass Study
"Low Maintenance"

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The 1985 Results of High- and Low-Maintenance
Kentucky Bluegrass Regional Cultivar Trials
N . E . Christians

In 1980, the United States Department of Agriculture (USDA) initiated a
regional Kentucky bluegrass cultivar trial that is presently being conducted
at most of the northern agricultural experiment s t a t i o n s .
The test consists
of 84 cultivars, with each cultivar replicated three t i m e s .
Two separate trials are underway at Iowa State U2 n i v e r s i t y .
One is a
h i g h - m a i n t e n a n c e study that receives 4 lb N/1000 f t
and is irrigated2 as
needed; the other is a low-maintenance study that receives 1 lb N/1000 f t in
September and is not i r r i g a t e d . The objective of the high-maintenance study is
to investigate the performance of the 84 cultivars under a cultural regime
s i m i l a r to t h a t used on irrigated home lawns in I o w a .
The objective of
the low-maintenance study is to observe the performance of the 84 cultivars
under conditions similar to those that would be used in a p a r k , school y a r d ,
or other low-maintenance a r e a s .
The low-maintenance study was established in
September 1980 and the high-maintenance study in August 1981.
The values listed under each month in Tables 1 and 2 are the averages of
ratings made on three replicated p l o t s .
Yearly means of all the months in
w h i c h data were taken are listed in the last c o l u m n .
The first cultivar
received the highest average rating for the entire 1985 s e a s o n . The cultivars
are then listed in descending order of average q u a l i t y .
The Least Significant Difference (LSD) value listed at the bottom of each
column is a statistical value that can be used to further evaluate the d a t a .
For cultivars to be considered different from one a n o t h e r , their mean quality
ratings must exceed the LSD v a l u e .
For e x a m p l e , the yearly means for the
high-maintenance cultivars must exceed 1.0, the LSD for that column (Table 1).
M i d n i g h t w i t h a mean reading of 7.9 performed better than Enmundi with a
reading of 6 . 8 .
H o w e v e r , the performance of Midnight was statistically the
same as Merit which had a yearly mean of 6 . 9 .
M i d n i g h t , N 5 3 5 , G l a d e , Ram-I, B r i s t o l , and Merit were the best of the
c u l t i v a r s in the h i g h - m a i n t e n a n c e trial (Table 1).
These cultivars have
consistently performed well over the past few years and can be considered to
be among the best cultivars for Iowa conditions on high-maintenance s i t e s . It
should be noted that the first 43 cultivars performed very satisfactorily and
any of them would be a good c h o i c e . There are also cultivars in the lower 50?
that have been observed to perform well in cultivar blends in other locations
at the research s t a t i o n .
As in past y e a r s , cultivars that performed well under high-maintenance
conditions did not do as well under low-maintenance c o n d i t i o n s .
Midnight,
which ranked first in the high-maintenance t r i a l , was 51st in the low-maintenance trial (Table 2 ) . C o n v e r s e l y , many of the poorer cultivars in high-maintenance areas were the best in the low-maintenance s t u d y . Cultivars K 3 - 1 6 2 ,

6

S . D . C o m m o n , S - 2 1 , and V a n t a g e , which performed best in the low-maintenance
t r i a l , ranked 8 2 , 7 8 , 8 3 , and 7 9 , respectively, in the high-maintenance t r i a l .
S u r p r i s i n g l y , Ram I which has done very well under both high- and lowmaintenance c o n d i t i o n s , fell to 53rd place in the low-maintenance trial, in
1985.
Ram I will be evaluated further in the spring of 1986 to determine if
there was some unusual disease or insect damage on this cultivar last y e a r .

7

Table 1.

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.

The 1985 quality ratings for the high-maintenance regional
bluegrass test established in the fall 1981.

Cultivar

May

June

July

Aug.

Sept.

Oct.

Midnight
N 535
Glade
Ram-I
Majestic
Bristol
Merit
243
Enmundi
MLM-18011
CEB VB 3965
WW Ag 478
Vanessa
Mosa
Bonnieblue
Charlotte
Eclipse
Kimono
SV-01617
Eclipse
Barblue
PSU-150
Aspen
Mer pp 300
K3-178
Birka
Fylking
ISU-190
Trenton
Columbia
Victa
BA-61-91
Cheri
Nugget
Baron
Dormie
Shasta
Enoble
Admiral
PSU-173
Holiday
Sydsport
Bayside
239
Touchdown

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

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

7.3
7.3
6.7
6.0
7.3
6.7
6.7
5.7
6.3
6.0
5.7
6.3
6.0
6.3
6.7
6.7
5.7
6.7
6.0
6.3
5.3
6.3
5.7
5.3
6.0
6.7
6.3
6.3
5.0
5.0
5.7
6.3
5.3
5.7
7.0
6.3
5.3
5.3
5.3
6.0
5.0
5.7
5.3
5.3
6.3

9.0
8.0
7.7
8.3
7.3
7.7
6.7
7.0
8.0
7.3
7.0
6.7
7.3
7.0
6.3
7.3
7.3
6.3
6.3
7.7
7.3
6.0
7.3
6.3
6.7
6.0
6.3
6.3
7.0
7.3
6.7
6.0
5.7
6.3
5.3
6.7
7.3
7.0
6.0
6.3
7.0
6.0
6.7
7.0
6.3

6.7
7.3
6.0
7.7
7.0
7.3
7.0
7.7
6.3
7.7
7.7
7.7
7.0
7.3
7.0
6.7
6.7
6.3
6.3
6.7
6.7
7.3
7.3
6.7
6.7
5.7
5.7
5.7
6.7
7.3
6.0
6.0
6.7
6.3
5.3
7.3
6.0
6.0
6.7
7.0
7.7
6.7
6.3
6.7
6.0

8.3
9.0
8.0
7.7
7.7
7.7
7.7
8.0
7.0
7.0
7.3
8.0
7.3
6.7
7.3
7.7
7.7
7.7
8.0
5.7
7.3
6.0
7.0
7.0
7.7
6.0
6.7
6.7
7.3
7.0
6.7
7.0
6.7
6.3
7.0
6.7
7.3
7.3
7.3
5.7
6.0
6.3
6.3
7.0
6.7

8

Kentucky

Mean

7.9
7.7
7.3
7.3
7.2
7.1
6.9
6.8
6.8
6.8
6.8
6.8
6.7
6.7
6.7
6.7
6.6
6.5
6.5
6.4
6.4
6.3
6.3
6.3
6.3
6.2
6.2
6.2
6.2
6.2
6.2
6.2
6.1
6.1
6.1
6.1
6.1
6.1
6.1
6.0
6.0
6.0
6.0
5.9
5.9

Table 1.

46.
47.
48.
49.
50.
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 1985 quality ratings for the high-maintenance regional Kentucky
bluegrass test established in the fall 1981.
(continued)

Cultivar

May

June

July

Aug.

Sept.

Oct.

Welcome
K3-179
Parade
Rugby
Geronimo
W W Ag PS 463
Bono
A20-6
Apart
Mystic
Adelphi
Banff
A 20
A 20-6A
Mona
225
Kl-152
Harmony
Mer pp 43
NJ 735
W W Ag 480
1-13
America
Cello
A-34
Merion
Argyle
Plush
H-7
SH-2
Kenblue
Piedmont
S . D . Common
Vantage
Monopoly
Wabash
K3-162
S-21
Lovegreen

4.7
5.7
5.3
5.7
4.7
5.7
5.0
6.3
5.7
4.7
6.0
5.7
6.3
6.3
6.0
6.0
5.3
5.7
5.3
4.3
5.0
5.3
5.0
5.7
4.7
5.3
4.3
5.3
5.3
4.3
3.3
3.7
3.7
4.0
4.7
3.7
3.3
3.3
4.0

6.0
6.0
4.7
4.0
6.0
4.3
5.3
4.3
5.3
6.0
5.0
4.0
4.3
4.0
4.0
4.3
4.7
5.0
5.7
6.0
4.7
4.0
4.3
3.7
4.3
5.3
4.7
4.3
4.0
4.0
3.0
4.3
5.0
5.3
4.7
4.3
3.7
4.3
4.3

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

6.0
6.3
7.0
6.7
5.7
6.3
5.7
6.7
5.3
6.0
7.0
6.7
6.3
6.7
6.7
5.3
6.0
6.0
6.3
5.7
6.3
7.0
6.3
6.3
6.0
6.0
6.0
5.7
5.7
6.3
6.3
6.0
6.0
5.3
5.7
5.7
6.3
5.3
4.7

6.0
7.3
6.0
7.3
6.0
6.0
5.3
7.7
6.3
6.3
6.7
7.0
7.3
7.0
5.7
6.7
6.3
5.0
5.0
6.0
5.7
7.3
7.3
6.3
6.7
6.0
6.3
6.3
6.3
6.0
7.0
5.3
5.7
5.7
4.7
6.0
5.3
5.3
4.0

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

5.9
5.9
5.8
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
5.6
5.6
5.6
5.5
5.5
5.4
5.4
5.4
5.4
5.3
5.2
5.2
5.2
5.1
5.1
5.1
5.0
4.9
4.9
4.8
4.7
4.3

LSD

1.3

1.5

1.4

1.3

1.4

1.5

1.0

0.05

Mean

Quality ratings are based on a scale of 9-1; 9 = best q u a l i t y , 6 = acceptable
q u a l i t y , 1 = poorest q u a l i t y .

9

Table 2 .

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.

The 1985 quality ratings for the low-maintenance
bluegrass test established in the fall 1980.

regional

Cultivar

May

June

July

Aug.

Sept.

Oct.

K3-162
S . D . Common
S-21
Vantage
Argyle
Parade
Ken blue
Bono
Plush
PSU-17
Piedmont
FyIking
Wabash
PSU-190
Dormie
Vanessa
Escort
Monopoly
Harmony
A-34
Bayside
Cheri
Kimono
Geronimo
N 535
PSU-150
Mer pp 43
Birka
Cello
Victa
Glade
Baron
Trenton
Holiday
Majestic
Shasta
NJ 735
Eclipse
K3-178
MLM-18011
WW Ag 463
H-7
Enable
SH-2
Merion

5.7
6.7
6.3
6.0
5.0
5.0
5.0
5.3
5.0
5.0
5.0
5.7
5.3
5.7
4.3
6.0
4.0
4.7
4.3
4.8
4.0
4.7
5.0
5.0
3.7
4.0
4.0
3.0
4.7
6.0
3.0
4.7
3.7
3.3
4.3
3.7
5.3
4.3
4.7
4.3
5.7
4.7
4.0
3.7
4.3

6.7
6.0
6.3
7.0
6.3
5.0
6.0
4.7
5.0
5.0
5.0
4.7
3.3
5.3
4.3
4.3
4.0
5.3
4.0
4.3
3.7
4.0
4.3
4.3
4.0
4.0
3.7
4.0
4.0
4.3
3.3
4.3
3.7
3.0
3.0
3.7
4.3
4.7
4.0
3.7
4.3
4.0
4.7
4.3
3.7

5.3
5.0
4.3
4.0
4.3
3.7
5.0
4.0
3.3
3.7
4.3
3.0
3.7
3.7
4.0
4.0
3.7
3.7
3.7
3.5
3.3
4.0
3.3
3.7
3.7
3.3
4.0
3.7
3.3
3.7
3.0
3.7
3.3
3.0
3.3
3.3
4.0
3.7
3.7
3.3
3.3
4.3
3.7
3.0
4.0

6.7
6.0
5.7
5.7
5.3
6.0
4.7
5.3
5.7
5.0
4.7
4.7
5.7
4.7
5.0
4.7
5.0
4.7
5.0
4.8
6.0
4.7
4.7
5.0
4.3
5.0
4.7
5.0
4.7
3.7
5.0
4.0
4.3
5.0
5.0
4.7
3.3
4.3
4.0
4.0
3.0
4.0
4.0
4.7
4.0

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

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

10

Kentucky

Mean

6.3
6.0
5.7
5.7
5.6
5.4
5.3
5.2
5.1
5.0
5.0
4.9
4.9
4.9
4.9
4.9
4.9
4.8
4.8
4.8
4.8
4.7
4.7
4.7
4.7
4.6
4.6
4.5
4.5
4.5
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.4
4.3
4.3
4.3
4.3
4.3
4.3

Table 2 .

46.
47.
48.
49.
50.
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 1985 quality ratings for the low-maintenance regional
bluegrass test established in the fall 1980. (continued)

Kentucky

Cultivar

May

June

July

Aug.

Sept.

Oct.

Nugget
239
Enmundi
Touchdown
Mosa
Midnight
M e r pp 300
Ram-I
243
A20-6
225
Admiral
K3-179
Barblue
America
A20-6A
Adelphi
Aspen
W W Ag 480
Merit
1-13
Kl-152
Rugby
Banff
CEB VB 3965
Apart
Sydsport
Bristol
BA-61-91
Mystic
Mona
Lovegreen
Bonnieblue
Charlotte
A20
Columbia
SV-01617
Welcome
WW Ag 478

4.0
4.3
3.0
5.7
4.3
4.3
4.0
5.3
3.7
3.7
4.0
4.3
3.7
4.0
2.7
4.0
3.3
4.0
5.0
4.0
4.0
3.3
3.0
4.7
4.3
4.0
5.0
4.5
3.3
4.0
4.0
4.0
3.7
3.7
3.0
3.3
2.7
3.7
3.0

3.0
3.3
4.0
3.7
4.0
3.7
3.7
5.0
3.3
3.7
4.0
3.7
4.3
3.7
3.7
3.0
2.7
3.7
3.7
3.3
3.3
3.7
3.0
4.0
3.3
3.3
4.3
4.0
3.3
3.0
3.7
3.7
2.7
4.0
3.0
3.3
3.0
3.7
3.0

3.3
4.0
3.7
3.3
3.7
3.0
3.7
3.7
3.7
3.3
3.0
3.3
3.3
3.3
3.3
3.3
3.0
3.0
3.7
3.3
3.0
3.3
3.0
3.7
3.3
2.7
3.3
3.0
3.0
3.3
3.7
3.7
3.3
3.0
3.0
3.3
3.0
2.7
2.7

4.0
4.0
4.0
3.3
4.0
4.3
4.0
2.7
4.3
3.7
3.7
4.0
3.7
4.0
4.0
4.0
4.0
3.7
3.0
3.7
4.0
4.0
3.7
2.7
3.3
4.0
2.7
3.0
3.7
3.7
2.7
3.0
3.7
3.3
4.3
3.0
3.3
3.0
3.3

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

5.3
5.0
4.3
4.3
4.0
5.0
4.7
4.0
4.7
5.0
4.3
4.3
4.3
5.0
5.0
4.7
4.3
4.7
4.0
4.3
4.3
4.0
4.3
3.7
4.3
4.3
3.0
4.0
4.7
4.0
4.0
3.3
3.3
3.3
3.7
4.0
3.7
4.0
4.3

4.2
4.2
4.2
4.2
4.2
4.2
4.2
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.0
4.0
3.9
3.9
3.9
3.9
3.9
3.9
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.8
3.7
3.7
3.6
3.6
3.6
3.6
3.4
3.4
3.4

LSD 0.05

1.8

1.4

1.1

1.6

1.7

1.8

1.1

Mean

Quality based on a scale of 9-1; 9 = best q u a l i t y , 6 = acceptable q u a l i t y , 1 =
poorest q u a l i t y .

11

Regional Perennial Ryegrass Cultivar Evaluation
K . L . Diesburg and N . E . Christians

This is the third year of data from the trial established in fall 1982
in conjunction with several identical trials across the country coordinated by
the U S D A .
The purpose is to identify regional adaptation of the 48 perennial
ryegrass c u l t i v a r s .
Cultivars are evaluated each month of the growing season
for turf quality and d i s e a s e .
2

The trial is maintained at a 2-inch mowing height with 4 lb N/1000 f t
through the growing season and is irrigated when needed to prevent d r o u g h t .
Preemergence herbicide is applied once in the spring and broadleaf herbicide
is applied once in September to control w e e d s .
The summer of 1985 was cooler than n o r m a l .
It is possible the usual
r a n k i n g of cultivars shifted against those that tolerate h e a t .
A l s o , the
monthly experiment means in Table 3 are higher in 1985 than in previous y e a r s ,
i n d i c a t i n g t h a t the c u l t i v a r s as a group performed better in the cooler
conditions.
Disease symptoms typical of those caused by Drechslera siccans occurred
at a low level of severity in S e p t e m b e r .
Four cultivars had the symptoms in
two or three of their three replications:
WWE 19, O m e g a , C o c k a d e , and NK
79309.
Most of the cultivars have allowed the encroachment of Kentucky bluegrass
since 1982.
Those having no bluegrass seedheads in May were:
HE-168, BT-1,
Manhattan I I , B i r d i e , WWE 19, and G a t o r .
Those having heads in only one of
their three replications were: G T - I I , P a l m e r , C u p i d o , O m e g a , C o c k a g e , LP 2 1 0 ,
LP 7 9 2 , NK 80389, and C i g i l .
This implies less than optimal establishment in
the one replication.
All other cultivars had seedheads in two or three of
This could imply either lack of competitiveness to
their three replications.
or compatability with Kentucky b l u e g r a s s .
Those with a significant level of
bluegrass invasion were:
Regal, Premier, B a r r y , C r o w n , C i t a t i o n , NK 7 9 3 0 7 ,
C o w b o y , NK 7 9 3 0 9 , and L i n n .
The 48 cultivars can be divided
turf quality:
1.

Excellent throughout the growing season
SWRC-1
Ranger

2.

into eight groups in decreasing level of

Palmer
Diplomat

IA 728
Fiesta

Slow spring green-up and excellent thereafter
Repell
LP 702
HE 168

BT-1
Manhattan II
Blazer

12

282
M 382
HE 178

Fair in spring and fall and good otherwise
Acclaim

Derby
Yorktown II

Pennfine
Regal

Fair to poor through July and good thereafter

5.

LP 736
Cowboy

Crown
Citation

Pennant
HR-1
2 ED
Sensitive to environmental

fluctuations
Delray
Cupido

Gator
Cockade

Birdie
Manhattan
Prelude

Fair throughout the growing season
WWE 19
Omega
Premier

LP 792
NK 80389
NK 79307

Barry
Elka
LP 210

Good only in August and September
Dasher
8.

Cigil

Poor throughout the growing season
Pippin

Table 3 .

Linn

NK 79309

3

Turf q u a l i t y , Kentucky bluegrass
of perennial ryegrass c u l t i v a r s .

invasion, and disease

ratings^

Bluegrass

Ratings
Cultivar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Mean

SWRC-1
LP 702
Repell
HE-168
Ranger
Palmer
Diplomat
Tara
Blazer
Manhattan II

6.7
6.0
6.3
6.3
6.0
6.7
6.7
5.3
6.3
5.0

7.7
6.7
6.3
6.3
7.7
7.7
7.7
6.3
6.7
6.3

9.0
9.0
7.7
9.0
8.7
8.0
8.3
7.7
8.7
8.7

8.0
7.7
9.0
7.0
7.7
7.0
7.7
8.7
7.3
7.3

9.0
8.7
9.0
9.0
8.7
8.7
8.7
9.0
8.0
8.3

8.7
9.0
9.0
8.3
8.3
9.0
7.3
8.7
8.7
9.0

8.7
8.3
8.0
9.0
8.3
7.3
7.7
8.0
7.7
8.7

7.3
8.3
8.3
7.7
7.0
7.3
7.7
7.7
7.3
7.7

8.1
8.0
8.0
7.8
7.8
7.7
7.7
7.7
7.6
7.6

13

0

Disease

9.0
9.0
9.0
9.0
9.0
9.0
6.3
9.0
9.0
9.0

%
7
7
3
0
7
3
10
0
10
0

Citation II
M 382
All Star
HE 178
Fiesta
Pennant
Pennfine
HR-1
Regal
Derby
Birdie
WWE 19
Manhattan
Omega
Birdie II
Premier
Prelude
Barry
Yorktown II
Gator
Crown
Acclaim
Cockade
Elka
Citation
Delray
LP 210
LP 792
NK 80389
NK 79307
Ovation
Cupido
Dasher
Cigil
Cowboy
NK 79309
Pippin
Linn

5.0
5.3
5.0
4.7
6.0
5.0
5.7
5.0
5.3
6.0
6.7
7.0
6.7
6.7
5.0
6.7
5.7
5.7
6.0
6.3
6.7
4.3
6.3
6.0
6.7
5.7
5.3
5.3
5.7
3.7
5.7
5.7
5.7
6.3
4.0
5.0
5.0
3.0

6.7
6.3
7.0
6.3
7.0
6.3
7.3
6.3
6.0
6.3
8.0
6.7
6.7
7.3
6.0
6.7
6.0
6.7
6.0
6.7
5.7
6.7
6.7
6.3
6.7
7.0
6.0
6.3
6.0
7.0
6.0
5.7
5.7
5.3
4.3
5.0
5.0
3.0

8.7
8.3
8.0
7.3
8.0
8.7
8.7
6.3
8.0
8.0
7.7
7.3
8.0
6.7
7.3
7.0
7.0
7.7
7.7
7.3
7.0
7.0
8.3
6.3
5.7
8.0
8.0
7.0
7.0
7.0
6.7
8.7
6.3
6.3
6.3
6.0
6.7
3.0

8.0
7.3
8.3
7.0
7.0
6.7
7.7
7.0
7.7
7.3
6.7
6.7
7.0
7.0
6.7
6.7
6.3
6.3
7.3
6.3
5.7
7.3
6.7
6.3
5.7
6.3
6.7
6.0
6.3
6.7
5.7
7.0
6.3
6.0
6.0
5.3
4.7
3.7

8.7
8.3
8.7
8.3
7.7
8.3
8.3
8.7
8.0
8.7
8.0
7.3
7.7
7.7
8.7
7.7
8.3
7.0
7.7
8.3
7.3
7.7
7.7
8.3
7.3
8.3
6.7
7.3
7.0
8.3
7.0
8.0
8.3
7.7
7.7
8.0
6.0
5.0

8.7
9.0
8.7
9.0
9.0
8.7
8.0
9.0
8.3
7.7
8.3
6.7
5.7
6.7
9.0
9.0
9.0
8.3
8.0
8.7
8.3
8.3
5.7
7.3
7.7
8.3
7.0
7.7
8.3
8.0
8.3
4.0
8.0
7.7
8.3
5.7
5.7
3.7

8.0
8.0
7.3
8.3
8.0
7.7
6.7
8.0
7.7
7.0
6.3
7.7
7.3
8.0
7.3
7.0
7.3
8.0
6.7
6.3
7.3
7.3
7.0
7.7
7.3
6.0
7.0
7.3
6.7
7.0
7.0
7.3
6.7
6.3
7.0
5.7
6.3
5.0

7.0
7.0
7.0
8.3
6.7
7.3
6.3
7.0
6.3
6.3
5.7
7.3
8.0
7.0
7.0
6.0
6.3
6.7
6.7
5.7
7.0
6.7
6.7
6.7
7.0
5.0
6.7
6.7
6.7
5.7
6.7
6.7
5.3
5.7
7.0
5.3
7.0
4.7

7.6
7.5
7.5
7.4
7.4
7.3
7.3
7.2
7.2
7.2
7.2
7.1
7.1
7.1
7.1
7.1
7.0
7.0
7.0
7.0
6.9
6.9
6.9
6.9
6.8
6.8
6.7
6.7
6.7
6.7
6.6
6.6
6.5
6.4
6.3
5.8
5.8
3.9

9.0
9.0
9.0
9.0
9.0
9.0
6.3
9.0
6.3
6.3
9.0
3.7
6.3
3.7
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
1.0
9.0
6.3
9.0
6.3
9.0
9.0
9.0
9.0
6.3
9.0
9.0
6.3
1.0
9.0
9.0

13
10
3
7
10
10
10
10
50
13
0
0
7
7
7
27
13
23
7
0
20
13
13
7
37
17
7
7
3
53
10
3
13
3
23
43
23
40

Experiment
Mean

5.7

6.4

7.5

6.8

8.0

7.9

7.3

6.8

7.0

7.9

13

LSD

1.5

1.3

2.0

1.7

1.3

1.2

1.4

1.3

0.8

3.5

25

a

b

c

0.05

Ratings based on a scale of 1 - 9; 9 = b e s t , 6 = a c c e p t a b l e , 1 = worst q u a l i t y ,
Ratings based on 9 = no disease and 1 = disease present in all replications,
Average of monthly quality r a t i n g s .

14
V"

v

Perennial Ryegrass Cultivar Evaluations
N . E . Christians

The 22 perennial ryegrass cultivars in this trial were among the first
p l o t s to b e e s t a b l i s h e d a f t e r the renovation of the field research area
in 1979.
The study has been maintained since
that time at a 2-inch mowing
2
height and is fertilized with 4 lb N/1000 f t / y r . The area receives no fungicide or insecticide a p p l i c a t i o n s .
B e l l e , F i e s t a , B l y e s , and Diplomat received the highest overall quality
ratings in 1985.
The first 16 cultivars received satisfactory ratings (Table
4 ) . NK-100 and Linn received the lowest ratings in 1985.

Table 4 .

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.

The 1985 quality ratings for 22 perennial ryegrass cultivars
lished in 1979.

estab-

Cultivar

May

June

Quality Ratings
July
Aug
Sept

Oct

MEAN

Belle
Fiesta
Blyes
Diplomat
Derby
Yorktown
Loretta
Citation
Delray
Elka
Caravelle
K5-94
Pennfine
K5-88
Manhattan
Med North
Goalie
Regal
J186 R24D
NK-200
NK-100
Linn

6.7
6.3
6.0
6.0
5.7
6.7
5.7
6.3
6.0
6.3
6.3
6.0
6.0
5.3
5.7
6.0
6.0
5.0
5.0
5.3
5.0
4.0

6.3
7.0
5.7
6.3
7.0
5.7
7.0
7.0
7.3
7.7
6.7
6.3
7.3
5.7
6.0
6.0
5.7
6.7
5.7
5.7
6.3
5.0

8.0
7.7
7.0
7.7
6.7
7.0
6.3
6.3
6.7
5.3
7.0
7.0
7.3
7.0
7.0
6.3
6.3
6.0
5.7
5.7
4.7
4.0

7.3
6.3
6.7
7.0
7.0
5.7
5.3
6.0
7.3
5.7
6.3
6.3
6.3
7.3
6.3
6.7
5.7
6.0
5.7
6.0
5.7
4.7

8.0
7.3
7.7
7.3
5.7
7.0
7.3
6.7
5.7
5.7
5.7
6.3
5.7
6.3
5.3
5.3
6.0
4.3
4.0
3.7
4.3
3.0

7.0
7.7
8.3
6.7
8.3
8.0
7.7
7.0
6.3
7.7
6.3
6.7
5.7
6.3
7.3
6.3
6.0
5.7
4.3
4.3
4.7
4.3

7.2
7.1
6.9
6.8
6.7
6.7
6.6
6.6
6.6
6.4
6.4
6.4
6.4
6.3
6.3
6.1
5.9
5.6
5.1
5.1
5.1
4.2

LSD

NS

NS

1.8

NS

1.4

1.2

1.0

0.05

15

Fine Fescue Cultivar Trial
K . L . Diesburg and N . E . Christians

This is the third year of data from the trial established in fall 1982.
The purpose is to identify regional adaptation of the 32 cultivars and blends
tested.
Cultivars are evaluated each month of the growing season for turf
quality and d i s e a s e .
2

The trial is maintained at a 2-inch mowing height with 4 lb N/1000 f t
through the growing season and is irrigated when needed to prevent d r o u g h t .
Preemergence herbicide is applied once in the spring and broadleaf herbicide
is applied once in September to control w e e d s .
Disease is usually a problem at this site during the s u m m e r .
At that
time, the necessary conditions of hot d a y s , warm n i g h t s , high h u m i d i t y , and
moist soil from irrigation combine to allow pathogens to t h r i v e . The summer of
1985 was cooler than normal and irrigation was not used as m u c h . C o n s e q u e n t l y ,
disease was not a p r o b l e m .
E x p e r i m e n t m e a n s in T a b l e 5 indicate the average performance of all
cultivars.
Fine fescues in central Iowa generally have lower turf quality in
August and best turf quality in O c t o b e r .
The influence of the cooler summer
in 1985 is seen a g a i n , where the cultivars as a group did best in J u n e , averaging an 8.4 r a t i n g .
Their worst performance was during April and November
when all cool-season grasses are close to winter d o r m a n c y .
Many of the cultivars have allowed the encroachment of Kentucky bluegrass
since 1982.
Tournament, D u a r , NK 8 0 3 4 8 , NK 8 0 3 4 7 , NK 8 0 3 4 5 , and Scaldis had
20-100% Kentucky bluegrass in two or three of their r e p l i c a t i o n s . FOF-WC and
Waldina have 100% Kentucky bluegrass in only one of their three r e p l i c a t i o n s .
This implies poor establishment in that r e p l i c a t i o n .
The 32 cultivars can be divided into eight groups in decreasing level of
turf quality:
1.

Excellent throughout the growing season
Checker
Banner

2.

Jamestown
Ensylva

Atlanta

Excellent the first half and good the second
Shadow

3.

Slow spring green-up and excellent thereafter
Biljart

Dawson

Aurora

Scaldis/Atlanta

Dawson/Pennlawn

16

4.

Good throughout the growing season
Barfalla

5.

FOF-WC

NK 79189
NK 80346

Fortress
NK 80345

Fair throughout the growing season
Agram

8.

Highlight

Poor in spring and fall and good otherwise
Banner/Checker
NK 79190

7.

Koket

Slow spring green-up and good thereafter
Scaldis

6.

Waldina

Wintergreen

Fair to poor throughout the growing season
Pennlawn
Tournament
NK 80348

Duar
NK 8037

Ruby
NK 79191

17

Table 5 . Turf quality ratings of fine fescue cultivars and b l e n d s .

Turf quality
Cultivar

Checker
Shadow
Atlanta
Dawson
Banner
Jamestown
Ensylva
Barfalla
Scaldis/Atlanta
Biljart
Aurora
Banner/Checker
Fortress
NK 80345
Koket
Dawson/Pennlawn
Waldina
Scaldis
NK 79189
NK 80346
FOF-WC
Highlight
Agram
NK 79190
Wintergreen
Pennlawn
NK 79191
NK 80348
Tournament
NK 80347
Ruby
Duar

Apr
c

C
C
C
CR
C
C
CR
C
H
H
CR
CR
C
H
H
CR
CR
S
C
C
CR
C
CR
CR
CR
H
CR
CR
H

May

Jun

Jul

8,

Aug

Sep

Oct

Nov

8..0
8.,0
9..0
7..3
9..0
8..7
7..7
9..0
9..0
9..0
8,.0
7..7
7..3
9..0
9..0
8..3
8..3
5,.3
9,.0 9. .0
8..7
8..3
8..3
8,.3
7..3
8..7
8..3 7. .7
8..0 7. .3
8..7
8..0
8..0
7..7
7..7
8,.3
8..3
7,.3
7,.0
9..0
8..0
6,.3
8..0
7..7
9..0
8..7
8..3
6..0
6..3
8..3
8..3
8..0
6..7
5..3
9..0
8.,0
8..0 7. .3
7..7
9.,0
8..3
6,.7
8..3
8..0
7.,0
8..7
8..3
5..3
7..3
9..0
6..7
8.,0
7..3
7..7
9..0
8..3
8..0
5..3
7..7
7..3
8..0
8..3
6..0
7.,0
7.,0
8..0
8..7
8.,0
5..3
7.,0
4..7
8..7
7..0
7..7
9..0
8,.0
6,.3
7..0
7..3
9..0
4,.7
8..0
7..7
7..3
9..0
6,.7
8,.3
7..0
7..7
7..0
8,.0
6,.0
8,.7
7..0
7..3
4..7
8..0
8,.7
7..3
7..0
6,.3
6,.3 7. .0
8,.7
7..0
6..7
8,.0
6,.3
7,.3
7..7
8..0
5..0
7..3
7..7
7..0
4,.7
6..0 7. .7
7..7
7..3
6,.7
5..0
5..0
7..3
7..0
6,.7
6..3
8..0
5..0
7..0
6..7
6..3
5,.3
7..3
7..0
4,.3
4..7
6..3
7..0
3..3

8..0
7..7
8..0
7..3
7..7
8..0
7..3
7..7
8,.3
8,.0
7..7
7..3
7..3
7..3
7..0
7..3
7..7
7.,0
8..3
7..3
7,.0
7..3
7,.7
7,.3
6,.7
7..0
7..0
7..0
7..0
6,.7
6..7
7,.0

8.,0
8,.7
6..7
8..0
8,.0
8..3
8..7
9..0
8,.3
7..7
8..0
8,.0
8.,0
8..0
8,.0
7..3
8,.0
7..7
8..3 7. .7
8..0
8,.0
5..7
7..7
6..7
8,.0
6.,0
8..0
7..3
7..3
8..3
7..3
8..0
7..3
8,.0
7..3
6..7
7..3
6..7
7..3
7..3
7..7
7,.3
7..0
6,.3
7,.7
6,.7
7,.7
7..7
7..3
5..7
7..0
6,.7
5..0
6..0
6,.0
6,.0
7,.0
5,.0
5..7
4..3
5..3
6,.0
5,.0

Mean

b

BlueGrass
%

8..3
8..2
8..2
8., 1
8., 1
8.,0
7..9
7..9
7..9
7..7
7..6
7..6
7..5
7..5
7..5
7..5
7.,4
7..4
7..4
7..4
7..3
7..3
7..3
7..2
7..1
7..0
6..7
6,.5
6..4
6,.3
6,.3
5,.5

0
0
0
0
7
17
7
0
0
20
17
0
17
43
0
3
33
40
7
3
33
3
7
20
0
13
27
40
63
40
7
63

Experiment Mean

6,.2

7..2

8..4

7..8

7..5

7..4

7,.5

6,.9

7..4

17

LSD = 0.05

1,.0

1..2

0,.8

1..5

1..3

1..1

1,.0

0,.9

0,.6

35

£

Quality rated on a scale of 1 - 9; 9 = best and 1 = w o r s t .

b
Average of monthly quality r a t i n g s .
C

Chewings (C), creeping red (CR), sheep (S), or hard fescue

18

(H).

Fine Fescue Management Study
N . E . Christians

The fine fescue management study includes the following cultivars:
1.
2.
34.
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

Each cultivar is maintained at two mowing heights: 1 and 2 inches. Each
2
plot is also divided into two fertilizer treatments: 1 and 3 lb N/1000 f t ,
a p p l i e d as I B D U .
The study was established on September 8 , 1979, and is
irrigated as n e e d e d .
The quality ratings in Table 6 are
replicated plots from May to O c t o b e r .
the only two grasses of the 10 included
tory overall quality mean for the entire

the means of monthly ratings taken on
Reliant and Scaldis Hard Fescue were
in this study to maintain a satisfacseason.

At the 2-inch mowing h e i g h t , none of 2 the cultivars maintained a satisfactory quality rating at the 1 lb N/1000 f t / y r fertility r a t e , although Reliant
and Scaldis
were both very close to an acceptable rating of 6 . At the 3 lb
2
N/1000 f t / y r rate R e l i a n t , S c a l d i s , A t l a n t a , Jamestown, E n s y l v a , D a w s o n , and
K5-29 maintained a satisfactory q u a l i t y .
At the 1 - i n c h m o w i n g h e i g h t , again none2 of the grasses maintained a
s a t i s f a c t o r y q u a l i t y a t t h e 1 lb N/1000 f t / y r r a t e .
Reliant,2 Scaldis,
J a m e s t o w n , and Atlanta were the best cultivars at the 3 lb N/1000 f t / y r r a t e .
This study has now been in progress for six s e a s o n s .
The fact that any of
these grasses have maintained an acceptable cover at a 1-inch mowing height for
that length of time is s u r p r i s i n g .
The cultivars listed as acceptable have
performed well consistently during the s t u d y .
The difference between poorly
rated cultivars and acceptable cultivars is large and the choice of fine fescue
cultivars for this region should be made c a r e f u l l y . Many are not well adapted
to Iowa c o n d i t i o n s .

19

Table 6 .

The effects of mowing height and nitrogen fertilizer on the quality
of 10 fine fescues.

Mowing Height
2 inch
1 inch
N Rate
Na Rate
1 lb
1 lb
3 lb
3 lb
b

c

Overall
Mean

5.2

4.6

5.9

4.9

5.2

6.9

5.7

7.4

6.3

Ruby Red Fescue

3.4

4.5

4.1

5.3

4.3

4.

Atlanta Chewings Fescue

4.6

6.1

4.8

6.4

5.5

5.

K5-29 Red Fescue

3.7

5.1

4.7

6.1

4.9

6.

Dawson Red Fescue

4.7

5.7

4.9

6.2

5.4

7.

Reliant Hard Fescue

5.7

7.6

5.9

7.9

6.8

8.

Ensylva Red Fescue

4.3

5.6

4.5

6.3

5.3

9.

Highlight Chewings Fescue

3.0

3.8

3.3

3.8

3.5

10.

Jamestown Chewings Fescue

4.6

6.2

4.9

6.5

5.5

a

k

1.

Pennlawn Red Fescue

3.9 »

2.

Scaldis Hard Fescue

3.

2

N rates are in lb N/1000 f t / y r .

The N source is I B D U .

Values are the means of monthly observations from May to O c t o b e r .

Q
Quality ratings are based on a scale of 9-1; 9 = best q u a l i t y , 6 = acceptable quality; and 1 = poorest q u a l i t y .

20

Tall Fescue Management Study
K . L . Diesburg and N . E . Christians

This is a report of the second year of data from the experiment.
It is
designed to compare the response of F a l c o n , H o u n 2d o g , Kentucky 3 1 , M u s t a n g , and
Rebel tall fescue at 0 , 2 , and 4 lb N/1000 f t / y r and cutting heights of 2
and 3 i n c h e s .
One pound of N was applied once during each month of May and
September for the 2-lb treatment and A p r i l , M a y , A u g u s t , 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 x 3 block within each
cultivar with the five cultivars replicated three times. A single application
each of DCPA in the spring and a phenoxy herbicide in the fall is sufficient
to control w e e d s .
Cultivar means in the last column of Table 7 show that the turf-type
cultivars were similar to each other and superior to Kentucky 31 over all
managements.
Monthly means show that Mustang and Houndog had better turf
quality than Falcon and Rebel in J u n e , J u l y , and August while in September,
Mustang alone was superior to all other c u l t i v a r s .
H i g h e s t q u a l i t y t u r f w a s o b t a i n e d with all cultivars at the 2-inch
cutting height and 4-lb N l e v e l .
Greater improvement was shown from 0 to 2
lb than from 2 to 4 lb N / y r .
The difference in quality between the 2- and
3-inch cutting heights became greater with each increment in applied N .
Mustang had a slower start in April than the other four cultivars. From
May through S e p t e m b e r , h o w e v e r , it was the only cultivar to have the best turf
quality at all fertility l e v e l s .
It continued as the best cultivar at the
4-lb level through November.
Rebel was comparable to Mustang the entire
s e a s o n a t the 4-lb l e v e l , and Houndog was comparable to Mustang where no
fertilizer was a p p l i e d .
Houndog was the only cultivar to perform the best at
the 2-lb level the entire s e a s o n .
Falcon did well at the 2- and 4-lb levels
during A p r i l , M a y , J u n e , A u g u s t , and S e p t e m b e r . At 0 - l b , h o w e v e r , it did just
a little better than Kentucky 3 1 .
Kentucky 31 was comparable to the other
cultivars at 2- and 4-lb levels in April but was inferior the rest of the
season at all fertility l e v e l s .
All cultivars produced higher quality turf at the 2-inch clipping h e i g h t .
K e n t u c k y 31 had p o o r turf quality throughout the growing s e a s o n , but its
ratings did not drop as much as those of the turf-type cultivars going from
the 2-inch to 3-inch clipping h e i g h t .
Improvement of turf quality at higher fertility levels for all cultivars
was due primarily to better color resulting from higher chlorophyll content
and less yellowing from d i s e a s e .
The turf-type cultivars also responded very
well to the 2-inch cutting height showing finer leaf texture and h i g h e r leaf
density.
Kentucky 31 responded with finer l e a v e s , but leaf density decreased
with a net small improvement of turf q u a l i t y .

21

A 3 - to 3 1 / 2 - i n c h c u t t i n g h e i g h t is traditionally recommended for
Kentucky 31 tall fescue t u r f .
This cultivar was released in 1943 for forage
and land reclamation p u r p o s e s .
It is not as well adapted for turf as are the
turf-type c u l t i v a r s .
The initial response of all perennial grasses to lower
clipping height is more diminutive growth giving a finer t e x t u r e . Only those
adapted to the stress of close clipping will persist over many y e a r s .
Data
f r o m f u t u r e y e a r s will allow assessment of the persistence level of each
cultivar.

22

Table 7 .

Means of turf quality ratings (9 = best) for tall fescue
c u l t i v a r s at t w o c l i p p i n g h e i g h t s a n d t h r e e fertility
levels.

Clip
N
Hgt
lb/ 2
(") 1000

Apr

Mustang

2
0
2
2
2
4
0
3
3
2
3
4
Average

2.3
3.7
5.0
2.0
2.3
3.0
3.1

Houndog

2
0
2
2
4
2
3
0
3
2
3
4
Average

Rebel

Cultivar

Jun

Jul

Aug

Sep

Oct

Nov

Mean

5.0
6.0
7.7
4.3
5.0
6.0
5.7

4.3
7.3
8.0
3.7
6.0
7.0
6.1

5.0
6.7
7.7
4.0
5.7
6.7
5.9

5.0
5.3
8.0
4.3
5.0
7.0
5.8

5.3
6.3
7.7
5.0
5.3
6.7
6.1

4.7
6.0
7.3
4.0
4.7
6.0
5.4

3.0
4.3
5.3
2.7
3.7
5.3
4.1

4.3
5.7
7.1
3.8
4.7
6.0
5.3

2.3
4.7
6.0
2.0
3.0
3.7
3.6

4.3
6.3
7.3
3.7
5.0
6.3
5.5

5.3
7.3
7.7
4.3
6.7
6.7
6.3

4.7
6.0
7.3
4.0
5.0
6.0
5.5

4.3
5.3
7.7
3.7
5.0
6.7
5.4

4.7
5.7
7.0
4.0
5.0
6.0
5.4

5.0
6.7
6.0
4.3
6.3
4.7
5.5

3.3
4.7
3.7
3.0
5.0
4.0
3.9

4.3
5.8
6.6
3.6
5.1
5.5
5.2

2
0
2
2
2
4
0
3
3
2
3
4
Average

3.0
5.0
5.7
2.0
3.0
3.3
3.7

4.7
6.0
7.7
3.7
4.7
6.0
5.4

4.0
6.7
7.7
2.7
5.7
6.7
5.6

4.0
6.0
7.3
3.0
5.0
6.3
5.3

4.0
5.0
8.0
3.3
5.0
6.7
5.3

4.3
5.3
7.0
4.0
5.3
6.3
5.4

5.3
6.3
6.7
4.3
4.7
5.3
5.4

3.3
4.3
5.0
3.7
4.7
5.7
4.4

4.1
5.6
6.9
3.3
4.8
5.8
5.1

Falcon

2
0
2
2
4
2
3
0
3
2
3
4
Average

2.3
4.3
5.0
2.0
3.7
3.7
3.5

4.3
6.0
7.3
3.7
5.0
6.0
5.4

4.0
6.7
7.7
3.0
5.3
6.7
5.6

4.0
6.0
7.0
3.0
5.0
6.0
5.2

4.0
5.0
8.0
3.3
5.0
7.0
5.4

4.3
5.7
7.0
3.7
5.0
6.3
5.3

5.0
6.7
6.3
4.0
5.3
5.3
5.4

3.0
4.3
4.7
2.7
4.0
4.3
3.8

3.9
5.6
6.6
3.2
4.8
5.7
5.0

Kentucky
31

2
2
2
3
3
3

0
2
4
0
2
4

2.3
4.0
5.3
2.0
3.3
3.7

3.0
4.7
6.0
3.0
4.0
5.0

2.7
6.0
6.3
2.3
5.0
5.3

3.3
4.7
5.3
3.3
4.0
4.7

3.3
4.3
6.3
3.0
4.0
6.0

3.7
4.0
6.0
3.3
4.3
5.3

3.3
5.3
6.0
3.0
5.0
6.0

2.0
3.7
5.0
2.0
4.0
5.3

3.0
4.6
5.8
2.8
4.2
5.2

LSD cultivar averages 0.7

0.4

1.1

0.6

0.4

0.5

0.4

0.6

0.3

LSD managements

0.6

0.6

0.4

0.6

0.8

0.6

0.7

0.4

0.9

May

23

Bentgrass Management Study
N . E . Christians

T h e b e n t g r a s s management study was established
includes the following species and cultivars:
Species
1.
3.
4.
5.
6.

Agrostis
Agrostis
Agrostis
Agrostis
Agrostis
Agrostis

in

the

fall

1980.

It

Cultivar

stolonifera Creeping Bentgrass
canina Velvet Bentgrass
stolonifera Creeping Bentgrass
stolonifera Creeping Bentgrass
stolonifera Creeping Bentgrass
stolonifera Creeping Bentgrass

Emerald
Kingstown
Penncross
Penneagle
Prominent
Seaside

Each cultivar planting is split into three fertility levels: 0 . 5 , 0 . 8 ,
a n d 1.2 lb N/1000 ft /growing m o n t h .
This Results in a total N application rate of 3 . 5 , 5 . 6 , and 8.4 lb N/1000 ft / y e a r .
The area was managed
a s a g o l f c o u r s e g r e e n , with a 3/32-inch mowing height and with applicat i o n s o f i n s e c t i c i d e s and fungicides as n e e d e d .
Each cultivar is replicated four times.
Penncross ranked first in the trials again this y e a r , but is so close to
P e n n e a g l e in yearly mean quality that they can be considered to be equal
(Table 8 ) .
Emerald ranked t h i r d , but it was statistically the same as Penncross and P e n n e a g l e .
Kingstown moved up one position from last y e a r ' s r a n k i n g , but this is due
to the fact that much of the Kingstown velvet bentgrass has died and surrounding bentgrasses have begun to take over these p l o t s .
Prominent and Seaside
have survived the past five s e a s o n s , but both have performed p o o r l y .
Quality of bentgrass increased with each increment of applied nitrogen
(T^ble 9 ) .
This is surprising because of the high N rates (8.4 lb N/1000
ft /year) that are being applied to some p l o t s . When the study was b e g u n , it
was anticipated that the high rate would be excessive and that plot quality
would deteriorate with t i m e .
After five s e a s o n s , we find that the 3.5 lb
N/1000 ft /yr is too low and that the best grass is found at higher fertility
levels.
The trend in the past few years has been to go to lower and lower fertility l e v e l s on b e n t g r a s s g r e e n s .
I still agree with the overall concept
involved in reduced N levels for b e n t g r a s s , but the research results from this
area would bring into question some of the things we have heard lately about
low-N p r o g r a m s .

24

Table 8 .

8

T h e 1985 q u a l i t y r a t i n g s
for six bentgrass cultivars with
averaged over four replications and three fertility l e v e l s .

data

Cultivar

May

June

July

Aug

Sept

Oct

MEAN

1.

Penncross

6.2

3.8

5.5

6.6

6.8

6.5

5.9

2.

Penneagle

5.2

3.7

5.8

6.5

7.2

6.3

5.8

3.

Emerald

5.8

4.3

5.2

5.5

6.2

5.6

5.4

4.

Kingstown

5.4

3.8

5.1

5.1

5.1

4.9

4.9

5.

Prominent

4.7

3.6

4.9

4.8

5.3

5.3

4.7

6.

Seaside

4.2

3.3

4.7

4.1

5.1

4.8

4.4

LSD

1.1

0.9

1.0

1.1

1.0

1.1

0.6

0.05

Quality ratings based on a scale of 9-1; 9 = best q u a l i t y , 6 = acceptable
q u a l i t y , and 1 = poorest q u a l i t y .

Table 9 .

The e f f e c t s
cultivars.

of

fertility

level

on

the

quality

of

Cultivar

0.5

lb N/growing season
0.8

1.2

1.

Emerald

4.5

5.3

6.3

2.

Kingstown

4.2

4.8

5.8

3.

Penncross

5.0

5.9

6.9

4.

Penneagle

5.0

5.8

6.5

5.

Prominent

3.9

4.9

5.4

6.

Seaside

3.5

4.3

5.4

six

LSD 0.05 for comparison of fertility levels within cultivar = 1.0.

25

bentgrass

Nitrogen X Potassium Study
K . L . Diesburg and N . E . Christians

T h i s s t u d y w a s initiated to observe the effects of nitrogen (N) and
potassium (K) on turf quality and vegetative growth of Kentucky bluegrass and
to evaluate the interactions between these two n u t r i e n t s .
The area was seeded with 'Baron' Kentucky ^Dluegrass in September 1979.
At the time of establishment, 1 lb Y 0^/1000 ft
(as triple super phosphate)
and 0.5 lb N/1000 ft
(as ammonium nitrate) were a p p l i e d .
The area is maintained in lawn condition including 2-inch mowing h e i g h t , pre- and postemergent
weed control, and irrigation as n e e d e d .
No insecticides or fungicides have
been a p p l i e d .
The study is arranged in a complete factorial with four levels of N and K
each at 0 , 2 , 3, and 4 lb/1000 ft /yr. A randomized complete block design is
used with 16 treatments and three r e p l i c a t i o n s . Urea is the N source and KC1
is the source of K .
Treatments are split over A p r i l , M a y , late A u g u s t , and
September.
M o n t h l y r a t i n g s o f t u r f q u a l i t y and fresh weights of clippings are
presented in Tables 10 and 11, r e s p e c t i v e l y . Benefit from K was not as great
as that from comparable amounts of N . The beneficial effect from increasing N
application levels was highly significant throughout the season for both turf
q u a l i t y and c l i p p i n g w e i g h t .
Increases occurred between the 0- and 2-lb
treatments and the 2- and 3-lb treatments but not between the 3- and 4-lb
treatments.
Higher levels of applied K seemed to cause slightly better turf
q u a l i t y and c l i p p i n g w e i g h t s b u t the d i f f e r e n c e s w e r e not s i g n i f i c a n t .
I n c r e a s e s seemed to occur between the 0- and 2-lb treatments but not any
others.
The n e e d for a p r o p e r balance of N and K can be seen in Table 10.
Although there was little interaction between N and K , optimum improvement cjf
turf quality from increments of applied N seemed to occur at 2 lb K/1000 ft .
Likewise, optimum stimulation of grass growth ^ n d turf quality from increments
of applied K seemed to occur at 2 lb N/1000 ft .
Turf quality was reduced to such an extent at low N levels that Kentucky
bluegrass stands were thin enough to allow germination and establishment of
crabgrass (Table 11).

26

Table 10. Turf quality
treatments.

N
lb/1000

ratings

8

of Kentucky

bluegrass

in response to N and K

K
fWyear

Apr

4
4

4
3
2
0

3.0
4.0
4.0
3.7

7.3
7.3
7.0
7.3

8.3
8.7
9.0
8.7

8.7
8.3
7.7
7.7

7.7
8.0
7.3
7.3

7.3
7.0
8.3
8.3

7.3
5.0
7.0
7.7

5.7
4.0
5.7
6.3

6.9
6.5
7.0
7.1

3
3
3
3

4
3
2
0

4.3
4.0
3.7
4.7

6.0
6.3
6.3
5.7

8.0
8.3
8.0
7.7

8.0
8.0
7.7
7.0

8.0
7.7
7.7
6.7

8.3
7.0
7.0
7.7

7.0
7.0
6.0
7.0

5.0
6.0
4.0
5.3

6.8
6.8
6.3
6.5

2
2
2
2

4
3
2
0

4.0
4.3
4.0
4.0

5.7
5.3
5.7
4.7

7.0
7.3
7.7
6.7

7.3
6.3
7.7
4.7

5.0
4.7
5.7
4.7

5.0
5.0
6.0
4.0

5.3
5.0
6.3
4.7

4.7
4.3
4.7
4.3

5.5
5.3
6.0
4.7

0
0
0
0

4
3
2
0

2.7
2.7
2.3
2.0

4.0
3.3
3.0
3.7

3.7
3.3
3.0
3.3

3.0
3.3
2.7
3.3

3.3
3.3
2.7
3.0

4.3
4.7
3.3
4.7

5.3
5.7
4.0
4.7

4.7
4.3
3.0
3.7

3.9
3.8
3.0
3.5

Experiment Mean

3.6

5.5

6.8

6.3

5.8

6.1

5.9

4.7

5.6

LSD = 0.05

0.5

0.6

0.6

0.8

0.8

1.0

1.2

1.1

0.6

4

May

Jun

Jul

Aug

Sep

Oct

Nov

Mear

Ratings based on a scale of 1-9; 9 = b e s t , 6 = a c c e p t a b l e , 1 = worst quality

27

Table 11. Mean effects of N and K on vegetative growth of Kentucky
and crabgrass i n f e s t a t i o n .

N
K
lb/1000 ft^/year

Aug 5

bluegrass

Crabgrass

Fresh Clipping Weights (grams)
Oct 16
Sep 20
Aug 28

Mean

%

4
4
4
4

4
3
2
0

74
95
46
57

78
83
50
62

70
46
48
50

45
39
31
41

67
66
44
53

0
10
0
0

3
3
3
3

4
3
2
0

66
72
79
38

93
78
83
46

73
64
52
59

54
42
47
38

71
64
65
46

0
3
10
10

2
2
2
2

4
3
2
0

28
19
73
15

13
11
42
9

17
18
47
9

10
12
35
8

17
15
49
10

13
3
7
27

0
0
0
0

4
3
2
0

2
4
5
6

1
2
2
3

15
11
11
12

3
2
2
2

5
5
5
6

53
40
70
57

Experiment Mean

42

41

38

26

37

19

LSD = 0 .05

28

23

16

12

19

12

28

Evaluation of Diffèrent Granular Nitrogen Sources
for Fertilization of Kentucky Bluegrass Turf
M . L . A g n e w , R . W . M o o r e , and N . E . Christians

In this s t u d y , eight granular N sources are being evaluated for maintenance f e r t i l i z a t i o n . The turf is Glade Kentucky bluegrass which was established in September 1984 and is maintained at a cutting height of 2 inches.
A
randomized complete block design with three replications is being u s e d . Plot
size is 3.5 X 7 f t .
The treatments include seven slow-release N sources applied at 4 lb N/1000
2
f t / y e a r s p l i t i n t o t w o equal applications 2 of N .
In a d d i t i o n , one urea
t r e a t m e n t w a s a p p l i e d a t 4 lb N / 1 0 0 0 f t / y e a r s p l i t i n t o f o u r e q u a l
applications.
The dates of fertilizer applications are May 1 and August 15.
The additional urea treatments were applied on June 1 and September 15.
Measurements to be taken i n c l u d e , monthly visual quality with particular
attention to disease d e v e l o p m e n t , density of t u r f , and color of t u r f .
Table 12.

Treatment
Number

List of t r e a t m e n t s .

Fertilizer
Source

Date of N
Application

1

Urea

May 1
June 1
August 15
September 15

1
1
1
1

2

IBDU (Estech)
(31-0-0)

May 1
August 15

2
2

3

SCU (Andersons, CIL)
(32-0-0)

May 1
August 15

2
2

4

SCU (Lakeshore, TVA)
(37-0-0)

May 1
August 15

2
2

5

M e t h y l e n e Urea (OMS)
(41-0-0)

May 1
August 15

2
2

6

UF (Blue Chip)

May 1
August 15

2
2

7

PCU (Estech)
(100 day release-rate)

May 1
August 15

2
2

8

Azolone (Noram)
(38-0-0)

May 1
August 15

2
2

29

lb N per2
1000 f t

Data taken during the summer of 1985 are listed in Table 13. While the
data are representative of an establishment y e a r , there were several differences.
U r e a , S C U / C I L , SCU/TVA, and Methylene urea consistently demonstrated
better visual q u a l i t y .
The d i f f e r e n c e s in c l i p p i n g yield and shoot density were very small and
inconsistent.
T h i s w o u l d not be surprising since the test area had not
completely filled in until August 1985.
The field area had sustained severe
winter damage during the winter of 1984-85 prior to the onset of t r e a t m e n t .
Further data will be collected in 1986, 1987, and

Table 13.

E f f e c t s of g r a n u l a r
and visual q u a l i t y .

sources

on

1988.

short

Shoot
Density
Sept.

Clipping Yield
Sept
June Aug

June

July

Urea
IBDU
SCU/CIL
SCU/TVA
Methylene
Urea
UF
PCU
Azolone

62.0
56.0
72.0
62.0
68.0

33.2
49.3
54.3
51.3
46.4

17.8
19.7
26.7
30.2
20.2

20.2
14.7
23.2
24.7
26.7

6.9
7.4
7.6
7.8
7.3

7.2
7.4
7.5
7.5
7.6

54.0
58.0
53.0

33.5
39.6
37.3

22.1
29.3
22.1

15.0
14.7
16.8

6.4
7.2
7.1

LSD 0.05

N.S.

14.2

N.S.

9.1

0.6

Nitrogen
Source

30

d e n s i t y , clipping

yield,

Visual Quality
Aug Sept Oct

Mean

8.2
7.7
8.3
8.5
8.5

7.6
7.7
7.7
7.7
7.7

9.0
6.2
7.4
7.3
7.2

7.8
7.2
7.7
7.8
7.7

7.3
6.8
7.4

7.4
7.8
7.5

7.5
7.8
7.2

6.1
7.8
6.2

6.9
7.5
7.1

N.S.

0.4

0.2

0.3

0.3

Summer Slow-Release Nitrogen Sources
Comparison Study
The purpose of this study was to compare eight slow-release N sources for
the summer application of n i t r o g e n . The turf is Glade Kentucky bluegrass which
was established in September 1984.
Treatments were initiated in the spring
1985 and w i l l continue for several y e a r s . Individual treatment plots measured
5 X 5 ft and they were randomized in a complete block design with three
r e p l i c a t i o n s . The turf was mowed at 2 inches and water was applied to prevent
drought s t r e s s .
Treatments include eight slow-release N sources applied at 2
ft^/season split into two equal applications
on May 20 and August
2
t r e a t m e n t received 2 lb N/1000 f t / s e a s o n of urea (46-0-0) split
equal applications on April 20 and September 10.
One additional
which included combinations of Powder Blue and u r e a , was added for
(Table 14).

lb N/1000
10.
Each
into two
treatment,
comparison

During the summer of 1985, visual quality was taken on a monthly b a s i s ,
shoot density was taken in S e p t e m b e r , and clipping yield was taken in J u n e ,
A u g u s t , and S e p t e m b e r . The data from summer 1985, as listed in Table 15, shows
that there was no difference in the response of each of the nitrogen s o u r c e s .
1985 is considered an establishment s e a s o n .
ed in 1986, 1987, and 1988.

Table 14.

Treatment
Number

Further data will be collect-

List of t r e a t m e n t s .

lbs N per
2
1000 f t

Date of N
Application

N
Carrier

April
May
August
September

1
1
1

Urea
Powder Blue
Powder Blue
Urea

2

April
May
August
September

1
1
1
1

Urea
FLUF
FLUF
Urea

3

April
May
August
September

1
1
1
1

Urea
Formolene
Formolene
Urea

1

31

April
May
August
September

Urea
Slo-Release
Slo-Release
Urea

April
May
August
September

Urea
IBDU
IBDU
Urea

April
May
August
September

Urea
SCU - TVA
SCU - TVA
Urea

April
May
August
September

Urea
SCU - CIL
SCU - CIL
Urea

April
May
August
September

Urea
Azolone
Azolone
Urea
1/4 - 3/4
1/2-1/2
1/2
3/4 - 3/4

April
May
August
September

Table 15.

Powder
Powder
Powder
Powder

Comparison of slow-release nitrogen sources in summer

Nitrogen
Source

Shoot
Density

Clipping Yield
June Aug
Sept

June

July

64.0
71.0
62.0
66.0
67.0
71.0
64.0
69.0
61.0

34.6
32.7
28.1
27.4
38.9
30.9
37.6
34.4
29.2

12.4
12.4
11.7
15.0
13.6
15.0
17.8
15.8
11.0

11.0
6.7
12.2
14.5
10.7
11.0
11.7
9.5
9.5

7.5
7.6
7.4
7.6
7.6
7.4
7.8
7.6
7.4

7.3
7.5
7.4
7.2
7.5
7.5
7.7
7.6
7.5

7.7
8.1
7.9
8.3
8.3
8.2
8.3
7.5
7.6

LSD 0.05

N.S.

N.S.

N.S.

N.S.

N.S.

N.S.

N.S. N.S.

32

fertilization.

Visual Quality
Aug Sept Oct

Powder Blue
Fluf
Formolene
Slo-Release
IBDU
SCU/TVA
SCU/CIL
Azolone
Powder Blue/
Urea

7.4
7.2
7.3
7.5
7.5
7.5
7.6
7.4
7.3

Blue/Urea
Blue/Urea
Blue
Blue/Urea

8.5
8.6
8.1
8.3
8.2
8.3
8.7
7.8
7.5

Mean

7.7
7.8
7.6
7.8
7.8
7.8
8.0
7.6
7.5

N . S . N.S

Evaluation of Liquid Fertilizer Programs
on Three Kentucky Bluegrass Cultivars
R . W . M o o r e , M . L . A g n e w , and N . E . Christians

T h i s study compares 12 liquid fertilizer programs using four nitrogen
sources on three Kentucky bluegrass c u l t i v a r s . The treatments were started in
the spring 1985 and will continue for several y e a r s .
The turf is maintained
at a cutting height of 2 inches and all clippings are removed.
T h e f o u r f e r t i l i z e r s include U r e a , Powder B l u e , F l u f , and F o r m o l e n e .
They were applied using different application schedules and2 three different
application r a t e s .
Each schedule received 2 4 lb N/1000 f t / g r o w i n g s e a s o n .
The balanced program required 1 lb N/1000 f t in each of the months of A p r i l ,
M a y , A u g u s t , and S e p t e m b e r . The heavy May program required 1/2 lb N in A p r i l ,
1 1/2 lb in M a y , and 1 lb N each in August and S e p t e m b e r .
The late fall
program required 1/2 lb N in A p r i l , 3/4 lb in M a y , 3/4 lb in A u g u s t , 1 lb in
September and 1 lb in N o v e m b e r .
The three cultivars of Kentucky bluegrass are Majestic (high-maintenance
g r a s s ) , Vantage (medium-maintenance g r a s s ) and Park (low-maintenance g r a s s ) .
E a c h c u l t i v a r w a s r e p l i c a t e d three t i m e s , and each of the 12 fertilizer
programs were randomized within each c u l t i v a r .
The data taken in 1985 include visual quality and clipping w e i g h t .
In
future y e a r s , carbohydrate r e s e r v e s , root d e n s i t y , and thatch development will
also be m e a s u r e d .
The field was seeded in the fall 1984 and sustained substantial winter
damage.
T h e r e f o r e , the turfgrasses were not ready for ratings until late
summer and early f a l l .
In a d d i t i o n , early snows in 1985 prevented ratings in
November.
In comparison of the cultivars (Table 16), the visual quality ratings were
generally better for Majestic than Vantage or Park; h o w e v e r , Majestic produced
only half as much clipping weight as Vantage or P a r k . This difference is not
s u r p r i s i n g , since Majestic is a prostrate-growing c u l t i v a r .
In comparison of programs (Table 17), the balanced and heavy May applications demonstrated better overall quality and shoot g r o w t h . The heavy May and
balanced programs produced greater shoot growth than the late fall p r o g r a m .
The lower quality of clippings from the late fall program is not surprising,
since only 1/2 lb N was applied in August while the other two programs received
1 lb e a c h . In the f u t u r e , clippings will be measured on a monthly b a s i s .
The individual fertilizer ratings suggest the widest difference of any of
the data t a k e n . Urea demonstrated the best visual quality followed by FormoClipping yields indicated the same
l e n e , F l u f , and Powder Blue (Table 18).
r e s u l t s with Urea producing the highest yield and Powder Blue the lowest.
Urea is a very quick release nitrogen source and Powder Blue a slow or delayed
release type n i t r o g e n .

33

In summary, 1985 was an establishment year for this s t u d y .
The data
reflect only the effects on establishment.
As the turfgrass matures and the
study p r o g r e s s e s , more conclusive results will be o b t a i n e d .

Table 16. T h e 1985 v i s u a l
cultivars.

quality

ratings

of

three

Kentucky

Clipping
3
Yield*
September

3

Cultivar

July

August

Ratings
September

October

bluegrass

Mean

Vantage

6.4

7.3

7.2

7.7

7.2

35.8

Park

6.5

6.9

7.0

7.5

7.0

30.8

Majestic

7.4

7.6

7.3

7.8

7.6

15.6

LSD = 0.05

0.07

0.29

0.09

0.13

0.11

Ratings based on a scale
poorest visual q u a l i t y .

of

1 - 9; 9 = best

visual

Clippings collected in September are in grams per 1.63 m

3.10

quality,

1 =

2

Table 17. The 1985 visual quality ratings of three liquid fertilizer p r o g r a m s .

3

Program

July

August

Ratings
September

October

Mean

Clipping
13
Yield
September

Balanced

6.8

7.4

7.2

7.7

7.3

29.0

Heavy May

6.8

7.7

7.3

7.7

7.3

29.9

Late Fall

6.8

6.8

7.1

7.6

7.1

23.3

LSD = 0.05

NS

0.29

0.09

Ratings based on a scale
poorest visual q u a l i t y .

of

NS

1 - 9; 9 = best

0.11

visual

quality,
2

Clippings collected in September are in g r a m s per 1.63 m .

34

3.14

1 =

Table 18. The 1985 visual quality ratings of four fertilizers.

3

Fertilizer

July

August

Ratings
September

October

Mean

Clipping
Yield
September

Urea

6.8

7.8

7.3

8.6

7.6

32.5

Powder Blue

6.8

6.7

7.1

7.6

7.0

21.9

Fluf

6.8

7.1

7.1

7.2

7.1

24.7

Formolene

6.8

7.6

7.2

7.4

7.3

30.4

LSD = 0.05

NS

0.33

0.11

0.15

0.13

Ratings based on a scale
poorest visual q u a l i t y .

of

1 - 9; 9 = best visual q u a l i t y ,

2
Clippings collected in September are in grams per 1.63 m .

35

3.62

1 =

1985 Preemergence Crabgrass Control Study
N . E . Christians and M . L . Agnew

T h e treatments of the 1985 preemergence crabgrass control trials were
applied on April 2 3 , 1985, with follow-up applications for some treatments
applied on May 2 5 . All treatments were immediately watered i n . The treatments
i n c l u d e d B e t a s a n 4 E - L F , B e t a s a n 2 . 2 S , and Betasan/Devrinol from Stauffer
C h e m i c a l ; S N 5 9 4 from Nor-Am; Ronstar 5 0 W P , Ronstar 2 G , and Ronstar/Modown
f r o m R h o n e - P o u l e n c ; D a c t h a l f r o m S D S B i o T e c h ; T e a m f r o m E l a n c o ; and
Pendimethalin 60WDG from 0 . M . S c o t t .
Spring 1985 was mild and crabgrass had germinated by the first week of
M a y . The mild spring was followed by extremely dry conditions in late spring
t h r o u g h the end o f J u l y .
The Kentucky bluegrass on this area went into
summer dormancy by late May due to the dry conditions and much of the early
crabgrass died because of lack of m o i s t u r e . The area was irrigated in mid-July
to bring the bluegrass out of dormancy; there was a second germination of
crabgrass in late J u l y . Crabgrass counts were made on the plot area on August
2 9 , 1985.
j
The o n l y t r e a t m e n t s to completely control crabgrass were the Betasan
4E-LF at 12.5 lb a i / A , both Betasan/Devrinol t r e a t m e n t s , the Ronstar 50WP at 8
lb a i / A , D a c t h a l at 10.5 lb with a 7.5 lb ai/A follow-up t r e a t m e n t , and
Pendimethalin 60WDG at 3 lb a i / A .
All of the treatments with the exception
of SN594 at the 1 lb/A rate significantly reduced crabgrass as compared to the
c o n t r o l . The SN594 was less effective than many of the other materials at the
2-lb/A rate but was found to be effective at the 4- and 6-lb/A r a t e s .
The
Ronstar m a t e r i a l s , D a c t h a l , T e a m , and Pendimethalin products were all quite
effective in controlling crabgrass at all rates tested
(Table 19).
Damage ratings were performed on the bluegrass at two w e e k s , one m o n t h ,
two m o n t h s , and four months following t r e a t m e n t .
There was no visible damage
from any of the treatments in the first 10 days after a p p l i c a t i o n .
By the
second w e e k , SN594 at the 6-lb/A rate and Ronstar 50WP at 4- and 6-lb/A rates
were observed to have a detrimental effect on the bluegrass (Table 19). Only
the Ronstar 50WP was observed to produce unacceptable damage after two w e e k s .
At the 1-month r a t i n g , only the Ronstar 50WP was observed to have a detrimental
effect.
All other plots had r e c o v e r e d .
At two m o n t h s , all plot areas were
dormant.
By the fourth m o n t h , all plots had recovered from drought d a m a g e .
There was no visible damage to any of the plots as they recovered from drought
stress nor was there any apparent damage at the fourth month r a t i n g .

36

Table 19-

Results of the 1985 preemergence weed control t r i a l s .

Treatment

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.

Rate
lb ai/A

Crabgrass

Control
Betasan 4E-LF
8
C
ri
8 + 4 '
Betasan 4E-LF
Betasan 4E-LF
12.5
Betasan 2.2S
7.5
Betasan 2.2S
12.5
Betasan/Devrinol
(7.5/1.5G)
4.875/0.975
Betasan/Devrinol
(7.5/1.5G)
7.5
/1.5
1
SN594
2
SN594
4
SN594
6
SN594
Ronstar 50WP
2
4
Ronstar 50WP
8
Ronstar 50WP
Ronstar 2G
3
Ronstar/Modown
2/3
4/6
Ronstar/Modown
Dacthal
10.5 C
Dacthal
10.5
/7.5
Team
1.5
2.0
Team
Pendimethalin 60WDG
1.5
Pendimethalin 60WDG
3.0
LSD 0.05

a
b

c
d

f

a

2 wks

Phytotoxicityk
1 mon
4 mon

26
1
1
0
7
2

9.0
9.0
9.0
9.0
8.5
9.0

9.0
9.0
9.0
9.0
9.0
9.0

9.0
9.0
9.0
9.0
9.0
9.0

0

9.0

9.0

9.0

0
33
10
2
7
2
1
0
1
2
1
1
0
3
5
1
0

9.0
9.0
8.5
9.0
7.5
8.5
7.5
5.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0

9.0
9.0
9.0
9.0
9.0
9.0
9.0
5.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0

9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0

9

1.1

0.2

N.S

f

Number of crabgrass plants in a 5 X 5 p l o t .
Phytotoxicity is rated on a scale of 9 to 1 ; 9 = no d a m a g e , 6 = accepta b l e , 1 = severe d a m a g e .
Plots measure
5 X 5 ft; four replications
2
liquids applied in 4 g a l water/1000 f t ,
Applied four weeks after the first t r e a t m e n t .
Follow-up treatments were made on May 25 for numbers 3 , 7 , 8 , and 2 0 .

37

1985 Preemeigence Annual Grass Timing Control Study
M . L . Agnew and N . E . Christians
The purpose of this study was to investigate the effectiveness of three
preemergent herbicides when applied at five different times during the s p r i n g .
The herbicides used (Dacthal, B e n e f i n , and Bensulide) were applied during the
first and third weeks of March and April and the first week of M a y . The area
chosen for the study was a lawn area on the ISU campus which is infested with
crabgrass and k o t w e e d .
Individual plots measured 5 X 5 f t . There were three
replications.
The environmental conditions recorded during summer 1985 were not t y p i c a l .
The summer began with a very dry period which inhibited crabgrass germination
in the Ames a r e a . Crabgrass germination did not take place for the most part
until m i d s u m m e r .
On August 2 7 , both percentage of knotweed coverage and number of crabgrass
plants per plot were recorded.
Crabgrass germination was spotty between
replications. H o w e v e r , trends demonstrated that knotweed was reduced by early
applications of D a c t h a l , while all treatments reduced crabgrass numbers (Table
20).
This study will be continued in future years
should provide more uniform crabgrass g e r m i n a t i o n .
Table 2 0 .

Weed control
study.

in the

at

a

new

1985 preemergence annual grass

Percent
Knotweed

Week

location

timing

which

control

Crabgrass
Numbers

Herbicide

Month

Dacthal
Dacthal
Dacthal
Dacthal
Dacthal

March
March
April
April
May

1
1
1
3
1

1.7
1.7
1.7
25.0
40.0

14
3
4
7
1

Benefin
Benefin
Benefin
Benefin
Benefin

March
March
April
April
May

1
3
1
3
1

35.0
6.7
24,7
35.0
63.3

4
20
3
8
3

Bensulide
Bensulide
Bensulide
Bensulide
Bensulide

March
March
April
April
May

1
3
1
3
1

63.3
45.0
13.3
45.0
43.3

4
1
2
5
8

27.0

31

Control

38

The Effect of Preemergence Herbicides on Root Inhibition
of Kentucky Bluegrass (Poa pratensis)
Z . J . Reicher and N . E . Christians

P r e e m e r g e n c e h e r b i c i d e s for the control of annual weeds are becoming
i n c r e a s i n g l y important to the turfgrass industry.
According to Lawn Care
Industry (9(6):1, 2 0 - 2 1 , 1985), lawn care companies alone were estimated to
have spent more than $43 million on these h e r b i c i d e s . The most widely used of
these herbicides include: Dacthal (DCPA), Balan (benefin), Betasan (bensulide),
and Ronstar (oxadiazon).
These herbicides are very effective in controlling annual weeds and thus
improving aesthetics; b u t , these chemicals may also have detrimental effects on
the t u r f . As reported in Agronomy Journal (67:563-565, 1975), studies done at
the University of Illinois showed that repeated treatments of the same herbi c i d e r e s u l t e d in increased leaf spot d i s e a s e , higher wilting tendencies,
reduced shoot g r o w t h , and increased thatch d e v e l o p m e n t . Reductions in rhizome
weight and length and a l s o , reduced overall turf quality in some s p e c i e s , due
to a p p l i c a t i o n s o f various preemergence h e r b i c i d e s , have been reported in
HortScience (17(6):911-912, 1982).
As indicated in HortScience (14:282-283,
1979), rooting of transplanted sod was decreased when preemergence herbicides
were applied either to the sod or sod b e d .
The objective of the following
s t u d y was to measure the effects of seven preemergence herbicides on root
inhibition of Kentucky bluegrass (Poa p r a t e n s i s ) .
The study was divided into high-maintenance and low-maintenance trials.
The high-maintenance trial received 4.0 lb of N yearly and was irrigated to
prevent moisture s t r e s s .
The area was mowed at 2.25 i n c h e s . The low-maintenance trial was mowed at 1.5 inches and received only 1.5 lb N yearly and no
irrigation.
T h e h i g h - m a i n t e n a n c e t r i a l consisted of four preemergence herbicides
a p p l i e d a t t h e r e c o m m e n d e d high and low rates and replicated four t i m e s .
Herbicide treatments (expressed as active ingredients) were Dacthal 75 WP at
10.5 and 15 l b / A , Ronstar 2 G at 2.0 and 3.5 l b / A , Betasan 4 EC at 7.5 and
14 l b / A , and Balan at 2 and 3 l b / A . (Note: Pendimethalin 60 WDG was mistakenly
applied at an excessive rate in this trial and was dropped from the s t u d y ) .
The herbicidesT were applied
on April 2 0 , to a 3-year old stand of Kentucky
f
bluegrass cv E n d m u n d i .
The soil on this area is a Nicollett (fine loamy
m i x e d m e s i c Typic Hapludoll) soil having a pH of 7 . 5 , 20 lb/A phosphorus
c o n c e n t r a t i o n , 1 6 0 - l b / A p o t a s s i u m c o n c e n t r a t i o n , and 2.3% organic matter
content.
The herbicides were thoroughly watered in with 2 inches of water
after a p p l i c a t i o n .
On June 5 , eight s a m p l e s , 20 cm d e e p , were taken from each treatment in
each r e p l i c a t i o n .
The vegetation and thatch were removed and the plugs were
divided into four d e p t h s , 0 - 5 , 5 - 1 0 , 10-15, and 15-20 c m . The roots were then
washed free of any s o i l , oven d r i e d , and w e i g h e d .

39

The low-maintenance trial consisted of four h e r b i c i d e s , all applied at
the recommended low rate and two of these applied at the high r a t e .
The
t r e a t m e n t s (expressed in active ingredient) were Bensulide 4 ELF at 8 and
12.5 l b / A , Pendimethalin 60 WDG (pendimethalin) at 1.5 and 3.0 l b / A , Ronstar 2
G at 3 lb/A, Dacthal 75 WP at 10.5 l b / A . This study was also replicated four
times.
The chemicals were applied on April 2 5 , and thoroughly watered i n .
This was on an old g o l f course fairway on a Webster (fine loamy mixed mesic
Typic Hapludoll) soil having a pH of 7 . 5 , 59 lb/A phosphorus c o n c e n t r a t i o n ,
196 lb/A potassium c o n c e n t r a t i o n , and 5% organic m a t t e r .
On June 2 5 , and again on August 8 , samples were taken as in the high-maintenance t r i a l , but divided into three depths; 0 - 5 , 5 - 1 0 , and 10-15 c m .
These
samples were w a s h e d , d r i e d , and weighed as in the other t r i a l .
In a d d i t i o n ,
these samples were ashed and the ash weights subtracted from the oven dry
weights to give the final r e s u l t s .
An analysis of variance was performed on the data at the termination of
the s t u d y .
The findings of the June sampling of the low-maintenance trial
were highly variable as demonstrated by the Ronstar having more root weight
t h a n the c o n t r o l .
T h i s is q u i t e surprising because in Agronomy Journal
(67:563-565, 1975), A . J . Turgeon reported oxadiazon to be quite damaging to
t u r f . This could be due to the variability in the old g o l f course s o i l s . The
o n l y h e r b i c i d e t h a t significantly inhibited rooting was the Pendimethalin
which was 18$ lower at the low rate than the control and 20% lower at the high
rate (Table 2 1 ) .
The August samplings in the low-maintenance trial showed less variability
and no significant differences among the h e r b i c i d e s .
But a g a i n , the Ronstar
treatment was rather high and the Pendimethalin treatments were l o w .
The high-maintenance study showed no significant differences
herbicides and the rates at which they were applied (Table 2 2 ) .

among

the

There were considerable differences between the high- and low-maintenance
trials with the low-maintenance trial showing more d a m a g e . This could be due
to a number of r e a s o n s , the first b e i n g , preemergent herbicides break down
faster with high-moisture than low-moisture c o n d i t i o n s .
T h u s , if the herbicides degraded quickly in the high-maintenance t r i a l , they had little time to
d o a n y d a m a g e to the r o o t s .
Another explanation is based on the faster
recovery ability of the turf in the high-maintenance t r i a l .
S o , even if the
turf was damaged to a certain e x t e n t , it recovered before it could be d e t e c t e d .
Preemergence herbicides can cause damage to turf under certain c o n d i t i o n s .
More research should be done to delineate exactly which c o n d i t i o n s , h e r b i c i d e s ,
and r a t e s p r o d u c e the d a m a g e .
Simpler and more accurate methods must be
established to check root inhibition caused by these h e r b i c i d e s .
Currently,
to obtain more conclusive r e s u l t s , the authors are undertaking an in vitro
study to investigate these e f f e c t s .
It is very important to remember that these are the results of only one
year's data on two locations. Much more work will be required before conclusions can be drawn concerning the effects of the herbicides on r o o t i n g .
At
this time, this information should not be used to make herbicide selection
decisions.

40

Table 2 1 .

Mean weights of low-maintenance rooting s a m p l e s .

Treatment

1.

Control

2.

Betasan 4 EC

3-

kg ai/ha

Ash weights (mg)
June
August

97.37

118.04

8.0

86.08

101.05

Betasan 4 EC

12.5

91.28

114.11

4.

Ronstar 2 G

3.0

107.07

112.71

5.

Dacthal 75 WP

10.5

96.90

111.52

6.

Pendimethalin 60 WDG

1.5

79.68

96.53

7.

Pendimethalin 60 WDG

3.0

78.25

99.97

17.54

N.S.

LSD = 0..05

Table 2 2 .

Mean weights of high--maintenance rooting s a m p l e s .

Treatment

lb ai/A

weight (mg)

241.04

1.

Control

2.

Dacthal 75 WP

10.5

210.43

3.

Dacthal 75 WP

15.0

207.31

4.

Ronstar 2 G

2.0

190.64

5.

Ronstar 2 G

3.5

189.55

6.

Betasan 4 EC

7.5

180.58

7.

Betasan 4 EC

14.0

240.71

8.

Balan 2 G

2.0

213.64

9.

Balan 2 G

3.0

199.24

LSD = 0,.05

N.S.

41

1985 Postemergence Annual Weed Control Study
N . E . Christians and M . L . Agnew

The 1985 postemergence annual weed control study was conducted between
the 7th and 8th fairways of Homewood Golf Course located on the east side of
Ames, Iowa.
T h i s a r e a w a s e s t a b l i s h e d m o r e t h a n 50 y e a r s ago and no
preemergence herbicides have been used on the s i t e .
The crabgrass population
on the area is generally quite h i g h .
The treatments included Acclaim from American Hoechst C o r p o r a t i o n , MSMA
(Daconate 6 ) , Tridephane from Dow Chemical C o m p a n y , and two experimentáis from
PBI Gordon - EH 795 and EH 8 0 5 .
The materials were originally to be applied at times through spring and
early summer to correspond to
1) the one- to two-leaf s t a g e ,
2) the firsttiller s t a g e , and
3) the mature stage of c r a b g r a s s .
Due to the very dry
spring and summer, h o w e v e r , the later treatments were shifted to midsummer
(July 29) and late summer (August 2 0 ) . These times of application corresponded
to the appropriate stages of late-germinating c r a b g r a s s .
The May 28 treatments of Acclaim and MSMA were not effective in controll
ing crabgrass (Table 2 3 ) . This is likely due to the extended dry period in the
summer of 1985 that began in late May and extended through late J u l y . The high
crabgrass counts were likely due to a second germination of crabgrass in late
J u l y . Much of the crabgrass that had germinated in May died in all plot areas
during the summer d r o u g h t .
Tridephane, applied on May 2 8 , was not effective in controlling crabgrass
at 1.0 lb a i / A , but did reduce crabgrass populations at the 1.5- and 2.0-lb/A
rates, although these reductions were not significantly lower than the c o n t r o l .
Tridephane applied at 1.0 lb/A on May 2 8 , and 1.0 lb/A on July 2 9 , completely
eliminated crabgrass from plot a r e a s .
The EH 795 was not effective in controlling
crabgrass when applied at a
2
single application rate of 5 oz/1000 f t .
H o w e v e r , in plots where follow-up
treatments were made with EH 795 10 days l a t e r , crabgrass counts were reduced
from 22 to 7 p l a n t s .
Single applications of EH 805 were as effective as the
r e p e a t e d a p p l i c a t i o n s o f EH 7 9 5 .
C o n t r o l w a s n o t i m p r o v e d by r e p e a t
applications of EH 805 (Table 2 3 ) .
The July 29 applications of Acclaim at both 0.12 and 0.18 lb/A completely
eliminated crabgrass in all treated p l o t s . The MSMA reduced crabgrass numbers
but was not completely effective (Table 2 3 ) .
Acclaim and MSMA applied to
mature crabgrass on August 20 reduced crabgrass numbers but the treatments
were not as effective as those applied at the first tiller stage of crabgrass
on July 2 9 .
The August 20 application of Acclaim appeared to damage treated Kentucky
bluegrass plots (Table 2 3 ) .
Close examination of damaged plants indicated no
d i r e c t damage to mature grass leaves but the material appeared to inhibit

42

tillering and growth of new plants from rhizomes which resulted in thinning of
plots.
This was the only time during the season that any damage to the plots
was observed in response to herbicide treatments.

Table 2 3 .

Results of the 1985 postemergence annual weed control s t u d y .

Treatment

Rate

Date of Application
May 28 July 29 Aug 20

Crabgrass

a

Phytotoxicity
Aug 2 9 , 1985

lb ai/A
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.

Control
Acclaim
Acclaim
MSMA
Acclaim
Acclaim
MSMA
Acclaim
Acclaim
MSMA
Tridephane
Tridephane
Tridephane
Tridephane
EH 795
EH 795
EH 805
EH 805

0.12
0.18
2.0
0.12
0.18
2.0
0.12
0.18
2.0
1.0
1.5
2.0
1.0/1.0
2
5 oz/1000 f t
5 oz/5 oz
5 oz
5 oz/5 oz

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

LSD 0.05

25
26
32
24
0
0
4
2
3
7
39
8
14
0
22
7
7
7

9
9
9
9
9
9
9
8
5
9
9
9
9
9
9
9
9
9

23

0.7

Number of crabgrass plants in a 5 X 5 ft plot on August 2 9 , 1985.
9 = no d a m a g e , 6 = a c c e p t a b l e . 1 = worst d a m a g e .

43

b

1985 Broadieaf Weed Control Study
N . E . Christians and M . L . Agnew

The 1985 broadieaf weed control study was conducted at Brookside Park in
A m e s , Iowa.
The Kentucky bluegrass turf area chosen had never been treated
w i t h h e r b i c i d e s and w a s h e a v i l y i n f e s t e d with broadieaf weeds including
the following species:
dandelion (Taraxacum o f f i c i a n a l e ) , broadieaf plantain
(Plantago m a j o r ) , field bindweed (Convolvulus a r v e n s i s ) , black medic (Medicago
l u p u l i n a ) , p r o s t r a t e knotweed (Polygonum o v i c u l a r e ) , ladysthumb (Polygonum
p e r s i c o n i a ) , C a n a d i a n thistle (Cirsium a r v e n s e ) , and p r o s t r a t e spurge
(Euphorbia maculata).
Treatments included X R M - 4 8 1 4 , TurfIon D , Starane 2 ,
and Formula 40 from Dow Chemical; and Trimec E s t e r , EH 791 (Turf E s t e r ) , EH 680
(Super T r i m e c ) , and Trimec from PBI Gordon (Tables 1 and 2 ) .
Treatments were made in three replications to 5 X 10 ft plots on June 2 0 ,
1985, in the equivalent of 50 g a l w a t e r / a c r e . The temperature was between 75
and 80°F at the time of application and there was no rain in the area for more
than 48 hours after treatment.
Counts of the number of each weed species per
plot were made on July 22 and again on August 2 9 .
By July 22, XRM-4814 had reduced dandelion numbers as compared to the
control; h o w e v e r , control at the 2.5-pt/A rate was unsatisfactory (Table 2 4 ) .
The 3.0- and 3.5-pt/A rate provided satisfactory control of d a n d e l i o n . All
rates of XRM-4814 were effective in controlling field bindweed and black m e d i c ,
b u t n o n e o f the r a t e s w e r e e f f e c t i v e in controlling prostrate k n o t w e e d .
Turflon D was very effective in controlling d a n d e l i o n , field b i n d w e e d , and
black m e d i c .
This material was effective in reducing prostrate knotweed as
compared to the c o n t r o l , but it did not completely eliminate this s p e c i e s .
Starane 2 reduced the population of most species of weeds as rates i n c r e a s e d ,
but it was not completely effective in controlling any of t h e m . Formula 40 was
effective against d a n d e l i o n s , but did not completely eliminate t h e m .
Field
bindweed and black medic were completely e l i m i n a t e d .
Prostrate knotweed was
not reduced by Formula 4 0 .
T h e EH 7 9 1 , EH 6 8 0 , and T r i m e c a t 3 . 5 - p t / A were very effective in
controlling d a n d e l i o n , field b i n d w e e d , and black m e d i c .
Prostrate knotweed
was controlled by EH 791 and EH 6 8 0 . This species was reduced by Trimec Ester
a t 2.0 p t / A and T r i m e c at 3.5 p t / A , but the knotweed was not completely
controlled by either m a t e r i a l .
The stand of Kentucky bluegrass on the area was thin and by August 29
many weed species had reinfested the plot areas (Table 2 5 ) . Plots treated with
the XRM-4814 at 3.5 p t / A , Turflon D at both r a t e s , the EH 7 9 1 , and EH 680 had
the lowest numbers of dandelions on August 2 9 . Prostrate knotweed populations
increased rapidly between July 22 and August 2 9 . Starane 2 , the EH 791 (Turf
Ester), and EH 680 (Super Trimec) were the most effective materials at limiting
reinfestation of k n o t w e e d . The ester formulations of Trimec tended to be much
more effective than the standard Trimec formulation against this s p e c i e s .

,

44

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1985 Phytotoxicity Tests
N . E . Christians
A phytotoxicity test to screen the effects of a variety of herbicides on
Penncross creeping b e n t g r a s s , Scaldis hard fescue, Pennfine perennial ryegrass,
and Falcon hard fescue was applied in a single replication on July 30, 1985.
The bentgrass was maintained at a 5/32-inch mowing h e i g h t .
The other three
species were maintained at a 2-inch mowing h e i g h t .
Temperatures were between
85-90°F at the time of a p p l i c a t i o n .
T h e c r e e p i n g bentgrass was very sensitive to all herbicides with the
exception of D a c t h a l , Pendimethalin, T e a m , and Betasan/Devrinol (Table 2 6 ) .
The SN 594 at 2-lb ai/A and the Acclaim damaged the bentgrass initially, but
the turf recovered by September 3 , 1985.
The only herbicide
perennial r y e g r a s s , and
4-lb ai/A r a t e s .
The
September 3 testing date
ai/A.

to cause unacceptable damage to the hard fescue, the
the tall fescue was Ronstar 50 WP at both the 2- and
only treated plot showing unacceptable damage at the
was the hard fescue treated with Ronstar 50 WP at 4-lb

47

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1985 Poa annua Control Study
M . C . Gaul and N . E . Christians

Annual bluegrass (Poa annua) is a weed that has presented turf managers
with serious problems for many y e a r s .
A variety of chemicals, including prea n d p o s t e m e r g e n c e herbicides along with plant growth retardants, has been
tested and used for annual bluegrass c o n t r o l .
If one word could be used to
sum up the results of all these chemicals in controlling annual b l u e g r a s s , it
would have to be the word "inconsistent."
The latest trend in controlling
a n n u a l bluegrass is the development of programs to successfully manage this
species as a turf; h o w e v e r , the search for effective chemical control still
continues.
Rubigan and chlorsulfuron are two chemicals that have been tested
for possible annual bluegrass control in the past two years at Iowa State
University.
T h e objectives of this study include determining appropriate
rates of both chemicals for controlling annual bluegrass and observing any
phytotoxic effects that may occur on the desired turfgrass species in the test
area.
Rubigan
R u b i g a n , produced by the Elanco C o m p a n y , is a systemic fungicide labeled
for controlling many common turfgrass d i s e a s e s .
It has also been observed
in some instances to gradually reduce annual bluegrass p o p u l a t i o n s .
Elanco
states there is no single rate that will effectively
control
annual
b
l
u
e
grass.
2
They do recommend rates of 0.2 to 0.4-oz/1000 f t applied every 2 to 3 weeks
d u r i n g t h e 2 s u m m e r d i s e a s e s t r e s s period until an accumulative amount of
2-oz/1000 f t has been r e a c h e d .
This field study was conducted over a 2-year period (1984-1985) at the
Iowa State University g o l f course on the east end of the practice putting
g r e e n . T r e a t m e n t s , applied beginning in mid-June
each y e a r , included rates of
2
0 . 0 5 , 0 . 10, 0 . 15, 0 . 2 0 , and 0.25 oz ai/1000 f t .
Each treatment was applied
to a 5 X 5 ft plot and replicated three t i m e s . The treatments were applied in
326 ml of water (equivalent to 150 g a l / A ) at 20 psi using a hand-held b o o m ,
o p e r a t e d in f o u r d i f f e r e n t d i r e c t i o n s to ensure uniform c o v e r a g e .
Each
treatment was applied eight times over a period
of
3.5
months
until
cumulative
2
amounts ranging from 0.40 to 2.0 oz ai/1000 f t were r e a c h e d .
Data were taken at periodic intervals during the study and included only
quality r a t i n g s .
The quality ratings were determined on a scale from 9 to 1;
with 9 = best q u a l i t y , 6 = a c c e p t a b l e , and 1 = dead t u r f . Clipping weights
were not taken because species were so dispersed throughout the plots that
separation would have been i m p o s s i b l e . At the termination of the s t u d y , final
ratios of annual bluegrass to creeping bentgrass were measured to determine if
differences among treatments e x i s t e d .
Response in this study varied with s p e c i e s , treatment r a t e s , and y e a r s .
In 1984, annual bluegrass showed increasing phytotoxicity (decreasing quality
ratings) with increasing rates of r u b i g a n .
Similar results were observed on
creeping b e n t g r a s s .
Overall mean quality ratings ranged from 8.3 to 6.3 for
a n n u a l bluegrass and from 8.6 to 5.5 for creeping bentgrass (Table 2 7 ) .
In

49

1985, annual bluegrass showed a very slight increase in phytotoxicity (decreasing quality ratings) with increasing rates of r u b i g a n .
Overall mean quality
ratings ranged from 8.9 to 8.1 for annual bluegrass and from 9.0 to 5.9 for
c r e e p i n g b e n t g r a s s (Table 2 7 ) .
As in 1984, creeping bentgrass showed an
increase in phytotoxicity with increasing rubigan treatment r a t e s .
At the
termination of this s t u d y , annual bluegrass to creeping bentgrass ratios were
measured and no signficant differences were observed between control plots and
treated p l o t s .
Results indicated that the annual bluegrass was more tolerant to increasing rubigan treatment rates than was creeping b e n t g r a s s .
The phytotoxicity
that occurred to the creeping bentgrass was a purplish-wilted condition that
persisted for up to two months after the final application at some of the
higher treatment r a t e s .
A l s o , quality ratings on both species tended to be
lower in 1984 than in 1985. This could be because the summer of 1984 was much
warmer and drier than the summer of 1985. As a r e s u l t , a d d i t i o n a l stress may
have been placed on the turf allowing for chemical stress to be more v i s i b l e .
Several logical reasons can be presented to support the results seen in
this s t u d y . F i r s t , it is important to remember that rubigan is not h e r b i c i d a l
in nature —
it will not kill a plant the way a herbicide w i l l .
Rubigan's
primary mode of action involves the inhibition of gibberellic acid synthesis
in susceptible plants such as annual b l u e g r a s s .
Gibberellic acid is a plant
hormone responsible for cell e l o n g a t i o n .
As a r e s u l t , susceptible p l a n t s ,
s u c h a s a n n u a l b l u e g r a s s , w i l l become reduced in size and eventually be
crowded out by the more aggressive and nonsuscepitble plants such as creeping
bentgrass.
One problem may be that such a competitive shift may take several
years before any actual reduction o c c u r s . A second reason is t h a t , perhaps in
this s t u d y , we are dealing with an annual bluegrass biotype that is resistant
to r u b i g a n .
Such chemical resistances are commonly observed among various
annual bluegrass b i o t y p e s .
Chlorsulfuron
Chlorsulfuron, produced by the DuPont C o m p a n y , is a postemergence herbicide used mainly for controlling various broadleaves and annual
grasses
in
1
f
f
cereal c r o p s .
It is labeled under the trade names of 'Glean and T e l a r .
T e l a r has been labeled for use in low-maintenance turfgrass areas such as
r o a d s i d e s . Brian M a l o y , a former ISU graduate s t u d e n t , tested the selectivity
of several cool-season turfgrass species to chlorsulfuron in the g r e e n h o u s e .
Maloy could adequately control annual bluegrass with rates of 2-oz a i / A . With
these observations, field studies were initiated to see if chlorsulfuron could
' also control annual bluegrass in the field.
The field study was conducted at two sites —
on the practice putting
g r e e n o f the I o w a State University golf course in Ames and on the third
fairway of the Hyperion Field Club in Des M o i n e s . Treatments were applied in
1984 and 1985 at the ISU golf course; Hyperion only received treatments in
1985.
Treatments included rates of 0 . 2 5 , 0 . 5 0 , 1.0, 2 . 0 , and 4.0-oz a i / A .
These were applied only once beginning in mid-June of each y e a r . The methods
used to apply the treatments and collect data were identical to those used in
the rubigan s t u d y .
Responses in this study varied with s p e c i e s , treatment r a t e s , y e a r s , and

50

sites.
At the ISU g o l f c o u r s e , creeping bentgrass appeared more tolerant of
c h l o r s u l f u r o n than did annual . bluegrass in both 1984 and 1985.
In 1984,
overall mean quality ratings ranged from 8.2 to 7.0 for creeping bentgrass and
f r o m 7 . 6 to 6 . 8 f o r annual bluegrass (Table 2 8 ) .
In 1985, overall mean
quality ratings ranged from 9.0 to 8.7 for creeping bentgrass and from 8.9 to
8.5 for annual b l u e g r a s s .
A g a i n , 1984 quality ratings are lower than those
f r o m 1985 .
T h i s is p r o b a b l y due to a warmer and drier summer in 1984.
Overall there is no significant annual bluegrass reduction at any treatment
level of c h l o r s u l f u r o n .
A t the H y p e r i o n s i t e , m u c h m o r e p o s i t i v e r e s u l t s w e r e s e e n w i t h
chlorsulfuron in terms of annual bluegrass c o n t r o l .
Increasing phytotoxicity
(decreased quality ratings) on annual bluegrass was observed with increasing
treatment r a t e s .
Overall mean quality ratings ranged from 9.0 at the control
level to 2.9 at the highest treatment l e v e l . The Kentucky bluegrass that was
in the plots showed no phytotoxic effects at all treatment l e v e l s .
U n f o r t u n a t e l y , one of the problems with this postemergence herbicide is
that it lacks the ability to prevent annual bluegrass from growing back into
voids left in the t u r f . This was a slight problem in our study as many of the
lower rate plots completely filled back in with annual bluegrass during the
cool fall m o n t h s .
F o r t u n a t e l y , h o w e v e r , the higher rate plots were slower to
fill back in with annual b l u e g r a s s .
This created less competition for the
existing Kentucky bluegrass and allowed for further establishment that hopefully in the long run would result in the conversion to Kentucky b l u e g r a s s .
S e v e r a l explanations can be offered to help explain why chlorsulfuron
controlled the annual bluegrass at Hyperion and not at the ISU golf c o u r s e .
Differences in soil c o n d i t i o n s , especially soil p H , can greatly affect herbicide a c t i v i t y . Soil tests revealed pH readings of 7.7 at the ISU golf course
and 6.9 at the Hyperion Field C l u b . This large pH difference between the two
sites may account for some of the differences o b s e r v e d . Another factor may be
leaching.
The putting green tends to contain much more sand and is irrigated
more often creating conditions ideal for the leaching of c h e m i c a l s . This may
also partially account for the poor control of annual bluegrass at the ISU
g o l f c o u r s e . This is a possible avenue of investigation for further r e s e a r c h .
F i n a l l y , perhaps we are dealing with two very different biotypes — one that
is tolerant of chlrosulfuron and one that is susceptible to i t .

51

Table 2 7 .

Rubigan quality

Rate/
Application

Species

(oz ai/1000
Annual
bluegrass

Creeping
bentgrass

Table 2 8 .

ratings.

Wk 6

Wk 15

Mean

Wk 6

1985
Wk 10

Wk 15

Mean

2

ft )

-0.05
. 10
.15
.20
.25

7.7
7.7
7.7
7.7
7.0
6.0

8.0
7.3
7.7
7.7
7.3
6.0

8.6
7.7
7.7
7.7
8.0
6.3

8.3
7.6
7.7
7.6
7.4
6.3

9.0
8.7
8.0
7.7
7.0
8.7

9.0
9.0
9.0
9.0
8.3
8.0

9.0
9.0
9.0
9.0
9.0
9.0

8.9
8.8
8.7
8.4
8.1
8.1

-0.05
.10
.15
.20
.25

8.0
7.3
7.7
7.7
7.7
6.0

8.7
8.3
8.0
7.3
7.0
6.3

9.0
8.3
7.3
6.7
6.3
4.7

8.6
7.9
7.7
7.0
7.0
5.5

9.0
8.7
8.3
7.0
6.3
6.0

9.0
8.0
8.3
7.7
7.0
6.0

9.0
9.0
8.0
8.3
7.3
6.0

9.0
8.6
8.5
7.9
7.3
5.9

Annual Bluegrass
Wk 4 Wk 10 Wk 15

Mean

Wk 4

Wk 10

Wk 15

Mean

Chlorsulfuron quality

Site

1984
Wk 10

Rate

ratings.

oz ai/A
Veenker 1984

-0.25
.50
1.00
2.00
4.00

7.3
7.3
6.0
6.3
7.0
6.3

7.0
7.0
7.0
6.3
6.0
6.7

8.0
7.3
7.3
7.7
7.3
7.7

7.6
7.2
6.8
6.7
6.4
6.8

8.0
8.3
8.0
8.3
7.7
8.3

8.3
9.0
8.7
8.0
8.3
7.7

8.0
7.6
7.7
7.0
7.3
7.0

8.2
8.1
7.9
7.7
7.1
7.0

Veenker 1985

-0.25
.50
1.00
2.00
4.00

9.0
8.3
8.3
8.3
7.7
8.3

9.0
9.0
9.0
8.7
8.7
9.0

9.0
8.7
9.0
9.0
9.0
9.0

8.9
8.5
8.9
8.8
8.6
8.8

9.0
9.0
9.0
9.0
9.0
8.3

9.0
9.0
9.0
9.0
9.0
9.0

9.0
8.7
8.7
9.0
8.7
9.0

9.0
8.9
8.9
9.0
8.9
8.7

Hyperion

-0.25
.50
1.00
2.00
4.00

9.0
3.7
3.7
3.3
2.3
2.0

9.0
8.3
6.7
7.0
5.0
3.0

9.0
8.7
8.7
8.3
7.0
3.7

9.0
7.0
6.3
6.5
4.9
2.9

52

— —

—

—

Rubigan Bentgrass Cultivar Study
M . C . Gaul and N . E . Christians

Initial field studies using rubigan for Poa annua control on golf course
p u t t i n g greens revealed a discoloration to the desired creeping b e n t g r a s s .
This discoloration appeared as a purplish-wilted condition that persisted for
s e v e r a l m o n t h s after the final applications were made at higher treatment
l e v e l s . The purpose of this study was to look at specific 2 bentgrass cultivars
and their response to the recommended rate (0.30 oz/1000 f t ) of r u b i g a n .
The study was intitated on June 2 0 , 1985, at the Iowa State University
Turfgrass Research Plots at the ISU Horticulture Research S t a t i o n , 10 2miles
north of A m e s .
Treatments were applied at a rate of 0.30-oz/1000 f t , at
2-week intervals
beginning
June 15 and ending October 1.
A total amount of
2
2.1-oz/1000 f t was a p p l i e d . Each treatment was applied to a 10 X 7 foot plot
2
and replicated four t i m e s . The treatments were applied in 2000 ml/1000 f t of
w a t e r at 20 psi using a hand-held b o o m . Cultivars tested included: E m e r a l d ,
K i n g s t o w n , P e n n c r o s s , P e n n e a g l e , P r o m i n e n t , and S e a s i d e .
T h e r e s u l t s s h o w e d t h a t the treated turf overall had slightly lower
q u a l i t y ratings than the untreated turf but all still had quality ratings
above the acceptable level (Table 2 9 ) . The only severe discoloration that did
occur was around 39 days after the initial application and this could probably
be attributed to the grass being under some additional stress from the very
warm temperatures in late J u l y .
O v e r a l l , Penncross, Penneagle, E m e r a l d , and
P r o m i n e n t s h o w e d t h e l e a s t d i s c o l o r a t i o n response to rubigan treatments.
Seaside and Kingstown appeared to be the least tolerant of rubigan treatments,
h o w e v e r , the low quality ratings for the Seaside control plots suggest that it
may not be the ideal bentgrass cultivar for use in this a r e a .
There were no visible effects of 1985 treatments in the spring of 1986.

53

Table 29-

The response of six bentgrasses to rubigan t r e a t m e n t s
season.

Cultivar

Days after first application
39
54
61
77
102

18

3

in the

108

M

b

Emerald
Treated
Untreated

9.0°
9.0

6.5
7.7

8.0
8.5

7.7
8.5

8.7
9.0

8.7
8.7

8.6
8.7

8.2
8.6

Kingstown
Treated
Untreated

9.0
9.0

5.5
7.7

7.7
8.2

7.2
8.2

8.5
9.0

8.7
8.7

8.0
8.7

7.8
8.5

Penncross
Treated
Untreated

9.0
9.0

7.5
8.2

8.2
9.0

8.0
8.7

8.7
9.0

9.0
9.0

9.0
9.0

8.5
8.8

Penneagle
Treated
Untreated

9.0
9.0

8.2
9.0

7.7
8.5

7.7
9.0

8.7
8.7

9.0
9.0

9.0
9.0

8.5
8.9

Prominent
Treated
Untreated

9.0
9.0

7.5
8.5

8.2
8.7

8.0
8.5

8.5
9.0

8.5
8.7

8.2
8.5

8.4
8.7

Seaside
Treated
Untreated

9.0
9.0

5.2
7.5

6.2
7.5

6.2
7.5

6.5
8.0

7.5
8.2

6.7
8.0

7.7
8.0

LSD = 0.05
a

13

Q

^

N.S.

Treatments applied
11 and 3 0 .

d

1.24

.77

.63

.45

.43

.43

June 2 0 , July 8 and 2 3 , August 6 and 2 1 , and

1985

.26

September

M = overall m e a n .
Each quality rating is the mean from four r e p l i c a t i o n s .
scale: 9 = best q u a l i t y , 6 = a c c e p t a b l e , and 1 = dead t u r f .

Quality

rating

LSD's compare treatment effects within cultivars and treatment effects among
cultivars.

54

LIMIT: Effects of a High-Concentration at Six Application
Dates on Kentucky Bluegrass
K . L . Diesburg and N . E . Christians
T

T

Limit was applied to B a r o n
Kentucky bluegrass at 10 lb ai/A on April
3 0 , May 3 , 6, 10, 13, and 17, 1985. The rate was four times higher than 2.5
lb a i / A . which is the recommended rate for t u r f . Treatments were applied to 5
X 5 ft plots through a hand-held boom with three fan jet nozzles passing two
feet above the ground via pressurized C O ^ from a tank strapped to the operator's b a c k .
The plots were arranged in a randomized complete block design
with four r e p l i c a t i o n s .
The mature turf was growing on a s a n d y , c l a y , loam
soil receiving 4 lb N/1000 sq ft/yr in the form of 37-0-0 sulphur-coated u r e a .
The only chemicals previously applied to the turf were Trimec on September 2 7 ,
1984, and Dacthal on April 2 2 , 1985.
Overhead irrigation was supplied to
prevent drought s t r e s s .
All plots were mown until May 9 .
Mowing did not
affect treatments previous to that date since the leaf blades there were no
longer elongating.
Any further mowing would have removed the heads from
subsequently treated plots.
After all treatments had been a p p l i e d , turf
q u a l i t y , canopy h e i g h t , and heading were recorded on three dates (Table 3 0 ) .
On May 28 the effects of all treatments on heading could be s e e n . By June 6,
heading was fully e x p r e s s e d , while plants in the plots receiving the first two
t r e a t m e n t s were recovering with renewed g r o w t h , and toxicity effects could
still be seen in plots receiving the last two treatments.
Data from July 4
record long range e f f e c t s .
Results
E f f e c t s on c a n o p y h e i g h t w e r e s t r a i g h t f o r w a r d .
Limit stopped leaf
elongation within 1 to 2 days after application and continued to stop growth
for 4 w e e k s .
By July 4 , there were no further treatment effects visible and
all plots had similar canopy h e i g h t s .
Toxicity effects were more c o m p l e x . Turf quality never dropped below the
acceptable level.
One m o n t h after the April 30 treatment, h o w e v e r , the
reduction in turf quality was greater than that at a similar time after each
of the other t r e a t m e n t s .
This could be due to the slower growth rate of
'Baron' at that t i m e .
It had not yet reached its p e a k , s p r i n g , vegetative
v i g o r . C o n v e r s e l y , two months after the May 10 treatment the reduction in turf
quality was less than that at a similar time after each other t r e a t m e n t . This
w a s the o n l y treatment where turf quality never dropped below 8 . 0 .
That
particular application occurred during a time of Baron's most vigorous vegetative g r o w t h .
H e a d i n g s t o p p e d at the m o r p h o g e n i c s t a g e it had achieved prior to
treatment and never resumed regardless of the application d a t e . As a r e s u l t ,
head emergence from superposing phytomers was prevented in the April 30 and
May 3 treatments while extruded heads were more or less partially hidden by
the leaf canopy in the other four treatments.
This can be seen by comparing
canopy heights with respective head heights in Table 3 0 .

55

Discussion
The lack of phytotoxicity at such a high rate of application was unexpected.
T h e e f f e c t s w e r e consistent across application d a t e s .
In c o n t r a s t ,
previous experiments have shown Limit to be less effective in summer and fall
a p p l i c a t i o n s . If results similar to this experiment can be obtained in turf at
lower levels of nitrogen and/or w a t e r , Limit should provide a means of reducing
spring labor costs for the turf manager without risking a severe reduction in
turf q u a l i t y .

Table 30.

Treatment
Date 1985

M e a n s o f t u r f q u a l i t y , canopy h e i g h t , h e a d i n g , and
r e s p o n s e to d i f f e r e n t dates of Limit treatments at
recommended application r a t e .

Canopy Height (cm)
May 28 Jun 6 Jul 4

Quality
May 28 Jun 6

5

Jul 4

head
four

Head Hgt (cm)
May 28 Jun 6

height in
times the

Heading
Jun 6

April 30

6.8

11.2

23.5

6.2

8.5

8.5

5.2

0.0

0.0

May

3

7.0

10.8

23.2

6.8

8.8

8.5

6.0

3.5

0.8

May

6

7.0

9.5

22.5

7.0

8.0

7.8

6.0

6.2

2.8

May

10

9.0

9.2

22.8

8.0

8.0

8.8

6.8

7.2

5.2

May

13

10.0

9.5

21.0

9.0

7.0

8.0

8.5

8.8

7.8

May

17

11.2

10.8

19.5

9.0

7.0

7.2

9.2

9.8

9.0

13.2

20.2

33.8

9.0

9.0

9.0

14.5

26.2

9.0

0.9

1.7

8.9

0.4

0.9

1.2

0.9

2.5

1.5

Control

LSD

b

Turf quality rated on a scale of 9 - 1; with 9 = best q u a l i t y , 5 = u n a c c e p t a b l e ,
and 1 = completely b r o w n .
b

Heading rated on a scale of 9 - 0; with 9 = 10055 and 0 = no h e a d s .

56

Evaluation of Fungicides for Control of Dollar Spot
on Penneagle Bentgrass—1985
L . E . Sweets

Trials were conducted on the Turfgrass Research Plots at the Horticulutre
Research S t a t i o n , A m e s , I o w a . Fungicides were applied to Penneagle bentgrass
m a i n t a i n e d at a 5/32-inch cutting h e i g h t .
Fungicides were applied with a
modified
bicycle
sprayer
at
30
lb
psi
and
a
dilution
rate of 5 gallons per 1000
2
ft .
The experimental design was a randomized block plan with four replications.
The plots were 4 X 5 f t . Fungicides were applied on a 7 - , 14-, 2 1 - ,
or 30-day schedule as indicated in Table 3 2 . Application began on May 29 and
continued through September 4 . Plots were evaluated for percent diseased turf
on July 20 and August 2 0 .
The trial was conducted in an area with a history of dollar spot and
Rhizoctonia brown p a t c h . Disease ratings for dollar spot were made by counting
the number of dollar spot infection centers per plot (Table 3 2 ) . May and June
were relatively c o o l , so the development of dollar spot was m i n i m a l .
Dollar
spot began to develop in m i d - s e a s o n , and disease pressure was light to modera t e . All plots showed good recovery from dollar spot by September 10. Daconil
2787 at 6.0 oz r a t e , B a n n e r , Banner + CGA 4 4 9 , and CGA 449 at the two highest
There were no symptoms of phytotoxicity with these
rates gave best c o n t r o l .
materials.

Table 3 2 .

Evaluation
bentgrass.

of

fungicides

for

2

Treatment

Rate (oz/1000 f t
Formulated Product)

Check
Duosan 75W
Tersan 1991 50 W
Dyrene 4F
Bayleton 25DF
Bayleton 25DF
Bayleton 25DF
Chipco 26019 50W
Daconil 2787 4.17F
Daconil 2787 4.17F
Fore 80W
Banner 1.1E/
Mancozeb 80W
Banner 1.1E/
Daconil 2787 4.17F
Banner 1.1E

control

of dollar

spot

in

Penneagle

8

Timing
(Days)

Disease R a t i n g
July 20
August 20

3.0
1.0
8.0
2.0
1.0
0.5
2.0
3.0
6.0
8.0

14
14
14
30
30
14
21
7 - 14
7 - 14
21

10.00
2.50
3.25
1.50
2.75
3.50
.50
.25
2.00
1.25
3.25

3.0

21

.50 a

3.0
1.0

21
21

.50 a
1.00 a

57

b
a
a
a
a
a
a
a
a
a
a

22.50
2.50
15.00
14.75
6.75
11.50
5.50
4.25
3.75
2.25
18.00

c
ab
be
be
ab
be
ab
ab
ab
a
c

7.25 abc
5.25 ab
2.50 a

CGA 449 50 W &
Banner 1.1E
CGA 449 50W
CGA 449 50W
CGA 449 50W
CGA 449 50W
Vorlan 50W

14
14
14
14
14
14

.42/0.5
.42
.56
.85
1.69
2.0

1.25
3.25
1.50
0.00
0.00
.74

a
a
a
a
a
a

2.50
8.50
8.25
1.25
1.00
15.00

a
be
be
a
a
be

Average of ratings from four replicated p l o t s .
Based on number of dollar
spot infection centers per p l o t .
Means in a column followed by the same
letter do not differ significantly (DMRT, P = 0 . 0 5 ) .

58

Evaluation of Fungicides for Control of Dollar Spot
on Emerald Bentgrass—1985
L . E . Sweets

Trials were conducted on the Turfgrass Research Plots at the Horticulture
Research S t a t i o n , A m e s , I o w a .
Fungicides were applied to Emerald bentgrass
maintained at a 5/32-inch cutting height with a modified bicycle sprayer at 30
lb psi and a dilution rate of 5 gallons per 1000 sq f t .
The experimental
design was a randomized block plan with four r e p l i c a t i o n s . The plots were 4 X
F u n g i c i d e s were applied on a 7 - , 14-, 2 1 - , or 30-day schedule as
5 ft.
indicated in Table 33Applications began on May 29 and continued through
September 4 .
Plots were evaluated for percent diseased turf on July 20 and
August 2 0 .
The trial was conducted in an area with a history of dollar spot and
Rhizoctonia brown p a t c h . Disease ratings for dollar spot were made by counting
t h e n u m b e r of dollar spot infection centers per p l o t .
May and June were
relatively c o o l , so the development of dollar spot was m i n i m a l .
Dollar spot
began to develop in m i d - s e a s o n , and disease pressure was light to moderate
(Table 3 3 ) .
Rubigan at 0.2 oz on a 7-day schedule, BRC 916/surfactant at a
1.12-oz rate on a 14-day s c h e d u l e , Prochloraz at both rates and in combination
with Actidione T G F , Daconil 2787 at 6.0-oz rate on a 7- to 14-day schedule and
Chipco 26019 F at a 2.0-oz rate and 21-day schedule gave the best dollar spot
control.
All plots showed good recovery from dollar spot by September 10.
BRC 916/surfactant at both rates caused a marked greening of p l o t s .
Greening
was noticed on June 26 (after two applications) and remained evident through
remainder of season.
There were no symptoms of phytotoxicity with other
materials.

Table 3 3 .

Evaluation
bentgrass

of

fungicides

for

2

Treatment

Timing
(Days)

Rate (oz/1000 f t
Formulated Product)

Check
Rubigan 50W
Rubigan 50W
Rubigan 50W
PP 450
PP 450
BRC 916 12.55SC/
surfactant
BRC 916/surfactant
Prochloraz 40EC
Prochloraz 40EC

control

.2
1.0

2.0

.56

1.12
.56

1.12
4.5

6.0

59

of

dollar

spot

on

Emerald

a

Disease R a t i n g
July 20
August 20

4
30
SA
14
14

10.25
0.75
5.50
5.25
0.50
0.25

c
a
ab
ab
a
a

46.25
4.50
8.25
12.75
21.50
10.00

d
a
ab
ab
be
ab

14
14
14
14

0.00
0.00
0.00
0.00

a
a
a
a

16.50
7.75
5.00
6.25

b
a
a
a

Actidione TGF 2.1W
Prochloraz 40EC +
Actidione TGF 2.1W
Prochloraz 40EC +
Actidione TGF 2.1W
Daconil 2787 4.17F
Chipco 26019 50W
Chipco 26019 50W
Chipco 26019 F
Chipco 26019 F
Daconil 2787 4.17F +
Actidione TGF 2.1W
Tersan 1991 50W

1.0

14

3.00 a

12.50 ab

3.0/1.0

14

0.25 a

4.00 a

4.5/1.0
6.0
1.5
2.0
1.5
2.0

14
7-14
21
21
21
21

1.5/.34
1.0

14
14

0.75
1.00
1.75
0.25
2.25
0.50

a
a
a
a
a
a

1.25 a
0.25 a

3.75
3.00
20.50
10.75
16.50
8.00

a
a
be
ab
b
a

10.50 ab
28.50 c

Average of ratings from four replicated p l o t s .
Based on number of dollar
spot infection centers per p l o t .
Means in a column followed by the same
letter do not differ significantly (DMRT, P = 0 . 0 5 ) .

60

Evaluation of Fungicides for Control of Bipolaris
Leaf Spot on Park Bluegrass—1985
L . E . Sweets
Trials were conducted on the Turfgrass Research Plots at the Horticulture
Research S t a t i o n , A m e s , Iowa.
Fungicides were applied to Park bluegrass
maintained at a 1 1/2-inch cutting height with a modified bicycle sprayer at
30 lb psi and a dilution rate of 5 gallons per 1000 sq f t . The experimental
design was a randomized block plan with four r e p l i c a t e s . Plots were 4 X 5 f t .
Fungicides were applied on a 7 - , 14-, 2 1 - , or 30-day schedule as indicated in
Table 3 4 .
Applications began on May 29 and continued through September 4 .
Plots were evaluated for percent diseased turf on July 20 and August 2 0 .
I n c i d e n c e o f leaf spot was light until mid-season but increased from
m i d - s e a s o n through September (Table 3 4 ) .
P r o c h l o r a z at a 4.5-oz r a t e ,
Prochloraz 3.0 oz + Actidione TGF .34 oz s c h e d u l e , Chipco 26019 SOW 2.0 oz and
Chipco 26019 F at 2.0 o z , PP 450 at 1.12 o z , Daconil 2787 at 6.0 oz and Duosan
at 3.0 oz rate gave the best c o n t r o l . No plots showed phytotoxicity s y m p t o m s .

Table 3 4 .

Evaluation of fungicides for control of Bipolaris leaf spot on Park
bluegrass.
2

Treatment

Rate (oz/1000 f t
Formulated Product)

Check
Prochloraz 40EC
Prochloraz 40EC
Actidione TGF 2.1W
Prochloraz 40EC +
Actidione TGF 2.1W
Prochloraz 40EC +
Actidione TGF 2.1W
Chipco 26019 50W
Chipco 26019 F
PP 450
PP 450
BRC 916/surfactant
BRC 916/surfactant
Banner 1.1 EC
Daconil 2787 4.17F
Daconil 2787 4.17F
Bayleton 25DF
Bayleton 25DF
Tersan 1991 50W
Vorlan 50W
Duosan 75W

Timing
(Days)

3.0
4.5
.34

14
14
14

1.5/.34

14

3.0/.34
2.0
2.0
.56
1.12
.56
1.12
1.0
3.0
6.0
1.0
.5
1.0
2.0
3.0

14
21
21
14
14
14
14
21
7-14
7-14
30
14
14
14
14

a

Disease R a t i n g
August 20
July 20
12.00
3.75
0.00
0.00

b
a
a
a

36.25
18.75
6.50
18.50

d
c
a
c

1.25 a

16.25 be

4.00
3.75
1.25
3.75
8.75
5.00
3.75
5.00
3.75
2.50
5.00
0.00
5.00
2.50
1.25

8.75
6.25
8.00
15.00
6.00
18.75
11.25
9.50
14.75
6.50
21.50
16.25
9.75
12.50
7.25

a
a
a
a
ab
a
a
a
a
a
a
a
a
a
a

a
a
a
be
a
c
abc
ab
be
a
c
be
ab
b
a

Average of ratings from four replicated p l o t s .
Based on a percentage of
diseased turf per p l o t .
Means in a column favored by the same letter do
not differ significantly (DMRT, P = 0 . 0 5 ) .

61

Pythium Root Dysfunction Field Studies
C . F . Hodges

Pythium root dysfunction is caused primarily by P . arrhenomanes and has
been found only on reconstructed, high-sand content golf greens on old golf
c o u r s e s . The disease usually occurs the first or second year after establishing the turf on the new g r e e n s . Infected plants begin to die during midsummer
heat stress in a pattern typical of Pythium blight; h o w e v e r , the Pythium is
restricted to the root systems of the p l a n t s .
There is no precise explanation for why P . arrhenomanes attacks bentgrass
r o o t s o n l y in high-sand content g r e e n s .
It a p p e a r s , h o w e v e r , that it is
a s s o c i a t e d w i t h i n a d e q u a t e microbiological competition in the s a n d .
The
P y t h i u m species appear to establish rapidly and to coexist with the grass
p l a n t s under mild growing c o n d i t i o n s .
Under s t r e s s , the infection of the
roots results in rapid death of p l a n t s . The disease may be severe for 3 to 5
years and necessitate reestablishment of the t u r f .
E v e n t u a l l y , h o w e v e r , the
severity of the disease d i m i n i s h e s . It is believed that the g r a d u a l establishment of a competitive microbiology in the sand eventually contains the activity
of the Pythium.
The p r i m a r y p r a c t i c a l p r o b l e m in dealing with this disease is that
existing fungicides and cultural techniques will not provide c o n t r o l .
In an
effort to discover a practical approach to controlling the d i s e a s e , bentgrass
plots were established on high-sand content greens at the Horticulture Research
Station at Ames (Fig. 2 ) .
Prior to seeding the p l o t s , P . arrhenomanes was
grown on 500 g of cornmeal in disposable aluminum p a n s .
One hundred pans of
infested meal were roto-tilled into the s a n d . Each of nine plots were planted
to P e n n c r o s s , E m e r a l d , and P e n n e a g l e .
Sets of three plots each received
cornmeal + Pythium, cornmeal a l o n e , or no cornmeal (controls). The plots will
be observed for disease development during the 1986 growing s e a s o n .
If the
disease is successfully e s t a b l i s h e d , the plots will be used for control s t u d i e s .

62

Figure 2 .

Root Pythium Study

Established

2.

Penne,ig le

2.

Penneagle

o
o
n
3.

Emerald
pi
+

1.

Penncross

1.

Penncross

'U
^
p*
Hr:

U

1.

Penneross

2.

Penncagle

2.

Penneagle

^
o
o

••!•••••• I

Y\

"

3,

Emerald

1.

Penncrosa

o
M

3.

Emerald

3.

Emerald

Penncross

^
o
o^

3.

Emerald

|
D3
M
+

2,

Penneagle

^
H§

rO

2.

Penneagle
•

i

1.

n

Penncross

M

o
o

n
o
>1
Ö
n>
p)
+

3.

Emerald

2.

Penneagle

rt
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Sod Reestabltshment Study
N . E . Christians

On September 19, 1980, a sod establishment study that included G l a d e ,
P a r a d e , Ram I , R u g b y , and Touchdown Kentucky bluegrass was established at the
research s t a t i o n . Each cultivar planting measured 20 X 12 ft and the study was
arranged in a randomized complete block design with four r e p l i c a t i o n s .
Data
were collected on this study until September 1982 when sod strength measurem e n t s w e r e t a k e n , t h e investigation was t e r m i n a t e d , and the results were
reported in an earlier
research p u b l i c a t i o n .
The study area was maintained
2
with 4 lb N/1000 f t / y r and mowed at a 2-inch mowing height during the 1983
season.
All sod was removed uniformly from the study area on May 19, 1984, at a
cutting depth of 0.5 i n c h e s .
The area was watered immediately after harvest
to prevent desiccation of the 2 severed r h i z o m e s .
The entire study area was
fertilized with 1 lb N/1000 f t in M a y , A u g u s t , and September of 1984 and 1985
and the area was irrigated to prevent drought s t r e s s . The objectives of this
part of the study are to observe the reestablishment of the five cultivars
from rhizomes and to determine if Kentucky bluegrass cultivars differ in their
reestablishment rate after h a r v e s t .
Parade and Ram I were the slowest to recover in the two seasons following
harvest (Fig. 1).
Rugby was intermediate through the 1984 season but was
e q u i v a l e n t to P a r a d e and Ram I in the 1985 s e a s o n .
Glade and Touchdown
recovered most quickly after harvest and maintained their advantage through
both 1984 and 1985.
On October 2 0 , 1985, sod tensile strength measurements were determined for
each cultivar and replication by attaching 18-inch wide sod strips to a scale
Three strips
and recording the pounds of pull required to break the p i e c e s .
were collected from each plot and the data were recorded as the mean of the
three measurements.
Three 4-inch wide X 4-inch deep plugs were collected
from the plots at the same t i m e . Each plug was evaluated for total number of
l i v e p l a n t s , t o t a l d r y w e i g h t o f a b o v e - g r o u n d t i s s u e , average number of
tillers per p l a n t , average number of rhizomes per p l a n t , and weight of rhizomes
per p l u g .
Sod strength, number of plants per s a m p l e , and dry weight of plants
not vary among the cultivars (Table 3 1 ) .
The average number of tillers
plant was highest for Parade and Ram I and lowest for T o u c h d o w n , G l a d e ,
Rugby.
The average number of rhizomes per plant did not v a r y , although
w e i g h t o f r h i z o m e s per 4-inch sample was greatest for G l a d e , followed
Touchdown.

did
per
and
the
by

The data collected on plant growth indicate that cultivars that put much
of their energy into tiller formation (above ground g r o w t h ) rather than into
rhizomes (below ground g r o w t h ) such as Parade and Ram I , recover more slowly
than cultivars such as Glade and Touchdown that appear to channel more energy
into rhizome p r o d u c t i o n .

64

The results of the study show that there are differences in recovery of
Kentucky b l u e g r a s s cultivars after harvest for s o d .
It is likely that this
differential recovery in areas originally established by seed to a predeterm i n e d c u l t i v a r b l e n d d o not maintain the same cultivar percentages after
regrowth.

Table 3 1 . Sod s t r e n g t h and plant growth measurements for
bluegrass cultivars reestablished from r h i z o m e s .

Cultivar

Sod
Strength

Plants/
Sample

Dry Wt
Plants

Average
Tillers/
Plant

the

five

Average
Rhizomes/
Plant

Kentucky

Weight
Rhizomes/
Sample

1.

Glade

33

64

3.5

0.19

1.1

1.7

2.

Parade

31

57

3.0

0.35

1.1

1.1

3.

Ram I

34

53

3.8

0.31

1.3

1.0

4.

Rugby

42

70

4.1

0.19

1.0

0.9

5.

Touchdown

39

73

4.2

0.10

1.0

1.2

NS

NS

NS

0.23

NS

0.5

65

Influence of Soil Compaction
on 14 Kentucky Bluegrass Cultivars
M . L . A g n e w , R . W . M o o r e , and N . E . Christians

In
section
was used
ment of

the f a l l o f 1 9 7 9 , 49 Kentucky bluegrass cultivars were seeded in
two of the turfgrass research a r e a .
In 1985, this cultivar trial
to evaluate the effects of soil compaction on the growth and develop14 of the Kentucky bluegrass cultivars.

S o i l compaction was applied by a smooth power roller which exerted a
static pressure of 2.5 kg cm
(35.5 16 in ). Compaction was applied on two
dates in 1985 (May 23 and June 19). Each application of compaction consisted
of 20 passes with the r o l l e r .
M e a s u r e m e n t s t a k e n in 1985 i n c l u d e d i n i t i a l thatch depth and shoot
d e n s i t y (Table 3 5 ) .
The results of the data indicated that the improved
cultivars are heavy generators of t h a t c h .
In g e n e r a l , the upright growing
common types of bluegrass had less thatch.
Two exceptions were Majestic and
Parade.
The percent reduction in shoot densities demonstrated that Ram I and
Baron were less affected by soil c o m p a c t i o n , while V a n t a g e , A d e l p h i , C o m m o n ,
G l a d e , P a r a d e , V i c t a , W a b a s h , and Park were most a f f e c t e d .
F u r t h e r data are scheduled for
appear in the 1987 Field Day R e p o r t .
Table 3 5 .

collection

in

1986.

The

will

The 1985 initial thatch depth and percent reduction of shoot
density by soil compaction of 14 Kentucky bluegrass cultivars.

Cultivar

Thatch Depth
(mm)

Sydsport
Common
Touchdown
Parade
Ram I
Park
Midnight
Baron
Victa
Majestic
Vantage
Glade
Adelphi
Wabash

18.7
15.0
19.3
14.3
22.7
12.3
24.0
15.7
24.0
13.7
15.7
23.3
18.3
14.3

15.5
23.9
17.3
21.5
5.7
20.4
19.2
8.9
21.4
17.1
24.6
21.7
24.1
21.6

7.9

12.0

LSD

results

Percent Reduction
of Shoot Density

Percent reduction of shoot density is the number of tillers in uncompacted
samples minus number of tillers in compacted samples divided by 100.
67

Turfgrass Cultivation Studies
M . L . Agnew and N . E . Christians

1.

Cultivation equipment comparison

In the fall 1985, a cultivation study was initiated on an area (Fig. 3)
which contained well over 1 1/2 inches of t h a t c h .
The purpose of this study
was to compare four core aerators and one vertical m o w e r in their capabilities
to remove excessive thatch from a Kentucky bluegrass s t a n d . The machines and
their characteristics are included in Table 3 6 .
The turf is a Northrup King
Premium Sod B l e n d , which was established in the fall of 1981 and was maintained
at a cutting height of 2 i n c h e s .
The treatments include five machines and three levels of intensity of
application (Table 3 7 ) .
All cultivation will be done in September of 1985,
1986, and 1987. Thatch depth will be measured the following s p r i n g .

2.

Cultivation intensity studies

In the spring 1986, a cultivation study was initiated on two a r e a s .
A
1-year-old stand of Midnight Kentucky bluegrass and the area adjacent to the
"Cultivation Equipment Comparison Study."
The purpose of this study is to
investigate the effects of core aeration and grooving on thatch prevention and
thatch r e m o v a l . The treatments are listed in Table 3 8 .

Table 3 6 .

Characteristics of 5 different pieces of cultivation

Equipment
Name

equipment.

Equipment Description

Ryan Ride-aire

Hollow t i n e , 3.5 inches center to center s p a c i n g ,
1/2-inch tine diameter

Ryan Lawn-aire III

Spoon t i n e , 3 3/4 x 7 inches center to center
s p a c i n g , 1/2-inch tine diameter

Ryan Lawn-aire IV

Hollow t i n e , 3 3/4 x 7 inches center to center
s p a c i n g , 1/2-inch tine diameter

Classen turf plugger

Hollow t i n e , 7 x 7 inches center to center s p a c i n g ,
5/8-inch tine diameter

Ryan Ren-O-thin

Flail k n i v e s , 1 inch s p a c i n g , 1/8 inch blade
thickness

68

Table 3 7 .
Treatment
Number

List of treatments for cultivation equipment c o m p a r i s o n .

Number of
Passes Over Area

Equipment Name

1
2
3

Ride-aire
Ride-aire
Ride-aire

OX
1X
2X

4
5
6

Lawn-aire III
Lawn-aire III
Lawn-aire III

OX
1X
2X

7
8
9

Lawn-aire IV
Lawn-aire IV
Lawn-aire IV

OX
1X
2X

10
11
12

Turf plugger
Turf plugger
Turf plugger

OX
1X
2X

13
14
15

Ren-0-thin
Ren-O-thin
Ren-0-thin

OX
1X
2X

Table 3 8 .

Treatment
Number

1
2
3
4
5
6
7
8
9

List of treatments for cultivation intensity s t u d i e s .

Cultivation
Equipment

Application
Timing

None
Core aerator
H
H
ti
n
H
H
Grooving machine

None
May
September
M a y , September
M a y , J u l y , September
May
September
M a y , September
M a y , September, July

«

«

h
n

H
it

69

70

Introducing the Iowa State University Personnel
Affiliated with the Turfgrass Research Program

D R . M I C H A E L AGNEW

Assistant Professor, Extension Turfgrass Specialist.
Horticulture D e p a r t m e n t .

D R . NICK C H R I S T I A N S

Associate P r o f e s s o r , Turfgrass S c i e n c e .
Research and T e a c h i n g . Horticulture D e p a r t m e n t .

M R . KEN DIESBURG

Turfgrass Graduate Student and Research A s s o c i a t e .
Horticulture Department Ph.D.
(Christians).

M R . M I C H A E L GAUL

Turfgrass Graduate S t u d e n t , Horticulture Department
M.S.
(Christians).

D R . M A R K GLEASON

Assistant Professor, Extension Plant Pathologist.
Plant Pathology

Department.

M R . ROBERT HARTZLER

Extension Weed A s s o c i a t e , Weed Science Department.

M R . YOUNG J00

Turfgrass Graduate S t u d e n t , Horticulture Department
Ph.D.
(Christians).
Associate Professor, Extension E n t o m o l o g i s t .
Entomology D e p a r t m e n t .

D R . DONALD L E W I S

D R . JAMES MIDCAP

Associate Professor, Extension Ornamental
H o r t i c u l t u r e . Horticulture D e p a r t m e n t .

M R . RICHARD M O O R E

Turfgrass Graduate S t u d e n t .
M.S.
(Christians/Agnew)

M R . ZACHARY REICHER

Turfgrass Graduate S t u d e n t , Horticulture Department
M.S.
(Christians)

71

Horticulture Department

Companies and Organizations which have made
donations to the Research Program
S p e c i a l thanks is expressed to the Big B e a r T u r f E q u i p m e n t C o m p a n y and
Cushman Turf for p r o v i d i n g a C u s h m a n T r u c k s t e r for use at the r e s e a r c h a r e a in
1 9 8 5 , to T r i - S t a t e T u r f a n d I r r i g a t i o n for p r o v i d i n g a G r e e n s m a s t e r III
Triplex G r e e n s m o w e r for use on the research g r e e n this y e a r , and to the Toro
C o m p a n y and T r i - S t a t e T u r f and I r r i g a t i o n for p r o v i d i n g a Toro 84 T r i p l e x
m o w e r for use in 1 9 8 6 .
Agro-Chem, Inc.
11150 W e s t Addison
Franklin Park, Illinois

Cushman Turf
5232 C u s h m a n
Lincoln, Nebraska

60131

W . A . Cleary Corporation
1049 S o m e r s e t S t r e e t
S o m e r s e t , New Jersey
08873

American H o e c h s t C o r p o r a t i o n
Agricultural Chemicals Department
Route 1 - Box 7
Brownsdale, Minnesota
55918

Dow C h e m i c a l
10890 B e n s o n
Shawnee M i s s i o n , K a n s a s

The A n d e r s o n s
Post Office Box 119
M a u m e e , Ohio
43537

Dupont Incorporated
1007 M a r k e t S t r e e t
Wilmington, Delaware

A q u a t r o l s C o r p o r a t i o n of America
1432 Union Avenue
P e n n s a u k e n , New Jersey
08110
Arcadian C o r p o r a t i o n
310 Clapp F a r m s Road
G r e e n s b o r o , North C a r o l i n a

27406

Elanco P r o d u c t s C o m p a n y
5600 South 42nd S t r e e t
Post O f f i c e Box 3008
Omaha, Nebraska
68103
Eli Colby C o m p a n y
Post Office Box 248
Lake M i l l s , Iowa
50450

Brayton C h e m i c a l Company
Post Office Box 437
W e s t B u r l i n g t o n , Iowa
52655

GrassRoots Turf
6143 S o u t h w e s t 63rd
Des M o i n e s , Iowa
50321

Britt Tech C o r p o r a t i o n
Post Office Box 216
B r i t t , Iowa
50423

Hawkeye C h e m i c a l C o m p a n y
Post Office Box 899
C l i n t o n , Iowa
52732
27049
International Seeds
820 F i r s t S t r e e t
Post Office Box 168
Halsey, Oregon
97348

Classen M a n u f a c t u r i n g
1403 Rouch Street
Norfolk, Nebraska
68701

72

66210

19898

Eagle Green C o r p o r a t i o n
Omaha, Nebraska
68103

Big Bear Turf E q u i p m e n t Company
1840 F u l l e r Road
W e s t Des M o i n e s , Iowa
50265

CIBA-Beigy C o r p o r a t i o n
Agriculture Division
G r e e n s b o r o , North C a r o l i n a

68501

Rhone-Poulenc Chemical Company
Black Horse Lane
Post Office Box 125
M o n m o u t h J u n c t i o n , New J e r s e y

Iowa Golf Course Superintendents
Association
Iowa Professional Lawn Care
Association

08852

Iowa Turfgrass Growers

Riverdale Chemical Company
220 East 17th Street
C h i c a g o , Illinois 60411

Iowa Turfgrass Institute
Lebanon Chemical Corporation
Country Club Fertilizer Division
Post Office Box 180
L e b a n o n , Pennsylvania
17042

0 . M . Scott and Sons
M a r y s v i l l e , Ohio 53040
SDS BioTech Corporation
Agricultural Chemical Business
2105 Spring Road
Oak B r o o k , Illinois
60521

Lesco Incorporated
300 South Abbe Road
E l y r i a , Ohio
44035

Spraying Systems Company
N Avenue at Schmale Road
W h e a t o n , Illinois
60187

Loft-Kellogg Seed
322 East Florida Street
Post Office Box 684
M i l w a u k e e , Wisconsin
53201

Stauffer Chemical Company
10250 Regency Circle
O m a h a , Nebraska
68114

M & A Enterprises
4346 South 90th
O m a h a , Nebraska
68127

Par Ex
Swift Agricultural Products C o r p .
518 Pauline Drive
Buffalo G r o v e , Illinois 60090

Mallinckrodt Incorporated
Post Office Box 5439
St. Louis, Missouri
63147

3M Company
Agricultural Products Division
233-IN-05 3M Center
S t . P a u l , Minnesota
55101

Monsanto Company
Agricultural Products Division
800 North Lindbergh Boulevard
S t . L o u i s , Missouri
63166

Terra Chemical Corporation
Box 218
Q u i m b y , Iowa 51049

Nor-Am Chemical Company
3509 Silverside Road
Post Office Box 7495
W i l m i n g t o n , Delaware
19803

The Toro Company
Irrigation Division
5825 Jasmine Street
Riverside, California

PBI/Gordon Corporation
1217 West 12th Street
Post Office Box 4090
Kansas C i t y , Missouri
64101

92504

Tri State Turf & Irrigation C o .
6125 Valley Drive
B e t t e n d o r f , Iowa 52722

Pickseed West Incorporated
Post Office Box 888
T a n g e n t , Oregon
97389

Union Carbide
Agricultural Products
A m b l e r , Pennsylvania
19002

Regal Chemical Company
A l p h a r e t t a , Georgia
30201

73

In the rush to prepare this information for the field day r e p o r t , some
c o m p a n i e s m a y h a v e i n a d v e r t e n t l y been m i s s e d .
If your company has
provided financial or material support for the research p r o g r a m , and is
n o t m e n t i o n e d a b o v e , p l e a s e contact me so your company name can be
added in future r e p o r t s .
Nick E . Christians

74