iSi'Y TO®!? TOg>!i®S

Issued By The

UNTIED STATES GOLF ASSOCIATION GREEN SECTION

ROOM 307, SOUTH BUILDING 
PLANT INDUSTRY STATION 
BELTSVILLE, MD.

BUILD NEXT YEAR’S TURF NOW

G.S.A. NINETEENTH ANNUAL TURF CONFERENCE AND SHOW: February 9 to 13 are the 
dates at the Book Cadillac Hotel, Detroit. The Green Section will have an educational 
exhibit. The best talent in the country will participate in the educational meetings.

STATE AND REGIONAL TURF CONFERENCES: To avoid conflicts and to facilitate travel 
arrangements for speakers, dates for winter conferences should be set soon. It is 
suggested that dates be registered with the USGA Green Section for coordination.

CRABGRASS: Crabgrass took a heavy toll of turf in 1947. Causes included (1) a cold 
wet spring which retarded growth of turf grasses and induced shallow root systems;
(2) unusually heavy attacks of He Lminthosporium (leafspot) which weakened turf 
grasses; and (3) soil compaction resulting from necessary mowing and foot traffic when 
soil was saturated. Crabgrass invaded putting greens on many courses where it has 
not been seen for years.

Chemicals suitable for crabgrass control have helped to reduce the popula­

tion and to thin the crabgrass to permit the successful reestablishment of turf 
grasses. The use of chemicals for this purpose is advantageous but unfortunately is 
not widespread. The principal emphasis in crabgrass control will continue to be 
placed upon the use of better adapted grasses and better fertilization and management.
The agronomic approach to crabgrass control is to shade the soil with turf 

grasses so dense and so vigorous that crabgrass has no chance to invade them. In the 
Washington, D. C., area the most crabgrass-free golf and lawn turf in 1947 was Bermuda 
grass and Zoysia. Of the two, the Bermuda grass is by far the more important because 
it is more naturally widespread.

The cultural approach to crabgrass control is to practice frequent brushing, 

discing or raking, with cutting to remove seed heads before they produce mature seed. 
Special flexible-tooth adjustable rakes in front of mower units have helped a great 
deal. Straight discs which are run in two directions cut crabgrass stolons and reduce 
the rate of vegetative spread. Heavy steel door mats, sections of chain-link fence, 
or Scotch chain harrows keep crabgrass roughed up so that mowers cut off the seed heads.

With the sharp frosts on September 25 to 28 over many sections of the country, 

crabgrass is nearly finished for this year. Now is the time to apply generous applica­
tions of fertilizer and lime (if needed) to build a strong deep-rooted turf for 1948. 
Every suitable means should be employed to loosen the soil in order to permit deep 
penetration of lime and fertilizers. Reseeding with adapted grasses should be done 
where needed. In many cases fertilization alone should be sufficient to reestablish the 
turf. On golf turf, it is important to establish grasses which can be cut closely with­
out injury and without unduly inviting crabgrass invasion.

There is no simple answer to the control* of crabgrass. No one method nor any 

one chemical is the complete answer. Growing good grass for dense turf is the most 
important factor but this becomes a difficult matter in a season like 1947, even for 
the most skilled superintendents. One of the guides to the suitability and acceptance 
of a new strain of any turf grass is its ability to prevent invasion of crabgrass even 
under unfavorable soil and climatic conditions and under abuses of management.

October, 1947

Timely Turf Topics, 1

MOWING SURVEY REPORT

Seventy-four reports were returned from 27 states. These were:

Clubs Reporting

Member Clubs in State

California
Colorado
Connecticut
Delaware
Illinois
Indiana
Kansas
Kentucky
Maine
Maryland
Massachusetts
Michigan
Minnesota
Missouri
Nebraska
New Hampshire
New Jersey
New Mexico
New York
North Carolina
Ohio
Oklahoma
Oregon
Pennsylvania
Texas
Virginia
West Virginia

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

60
10
32
7
61
24
5
13
5
20
52
39
22
24
10
3
51
7
139
23
58
11
9
105
43
24
18

The reports cover 68 courses which have bentgrass greens, 5 which have 

Bermuda grass greens (Texas 2), North Carolina (2), and Virginia (1), and 1 in Oregon 
which reported fescue greens.

Forty-two courses reported seeded greens; 26, vegetated greens.

Spring
Summer
Fall

Height of Cut

3/16"

18
17
16

1/4"

31
26
35

5/16" or higher

17
25
18

It appears significant that 52 percent of the clubs which reported do 
not change the height of cut of the putting green mowers at any time during the 
season. Of those clubs which do not change the height of cut, 46 percent cut at 
1/4-inch; 34 percent, at 3/16-inch; and the remaining 20 percent, between 
7/32—inch, 5/16-inch, and 3/8—inch.

Frequency of Mowing

Only two courses (North Carolina and Texas) reported daily mowing 

throughout the season. Frequency of mowing usually depends upon the amount of 
play, the weather conditions, and the rapidity of growth.

October, 1947

Timely Turf Topics, 2

The following table will indicate the extent of variation in the frequency 

of mowing practiced by clubs which reported.

Frequency of Mowing (Number of Times a Week)

Spring
Summer
Fall

1

1
1
2

2

2
3
4

3

20
15
22

4 

15 
23 
16 

5

8
8
8

6

22
16
15

7

3
6
2

Brushing

Fifty-five clubs reported that the greens are brushed and 14 reported no

brushing. Frequency of brushing varies from once a month to once each mowing. The 
practice of attaching brushes to putting green mowers is the one most commonly re­
ported.

Dollarspot

Only 2 clubs reported very severe attacks of dollarspot; 9, severe attacks; 

44, light attacks; and 15, no dollarspot at all. Ninety-two percent of the clubs 
which had dollarspot reported that this disease was controlled with ease. Dollarspot 
was included in this mowing survey because it has been observed repeatedly that 
“matting,” as the result of high (over 1/4-inch) mowing, infrequent mowing, and no 
brushing, produce conditions which are highly favorable to the fungus causing 
dollarspot. It is difficult to determine this correlation from the results of this 
survey because many clubs which have had difficulty in controlling dollarspot did not 
report.

Among the vegetated creeping bents, 21 clubs reported that they used 

Washington; 4, Arlington (C-l); 2, Cohansey (C-7); 2, Toronto (C-15); 2, Congres­
sional (C-19); 1, Norbeck (C-36); 1, Metropolitan; and 1, Old Orchard (C-52). There 
was no report on the use of Collins (C-27) bent.

It is recognized that the results of this mowing survey are incomplete; yet 
they represent an excellent cross section of many top-notch golf clubs and some which 
are struggling to attain perfection. It is regretted that the purpose of the survey 
has been misunderstood or ignored by many who could contribute valuable information 
for many smaller clubs which need guidance in their efforts to produce superior putting 
green turf. It is the sole intention of these surveys to point out the most desirable 
practices which produce superior turf.

Summary

The ’’best” height of cut for good putting surfaces is in the range of 3/16- 

inch to 1/4-inch.

It is better practice to maintain the same height of cut throughout the 

season except under extreme weather conditions or under very unusual circumstances. To 
miss scheduled cutting now and then may be a better practice than to change the height 
of cut.

The more often the putting green is mowed, the keener will be the surface, 

and the less will the the likelihood of developing a "mat".

Brushing becomes less of a necessity with closer, more frequent mowing, re­

gardless of the type of grass used.

Dollarspot increases in severity and is more difficult to control as "matting" 

increased because of high and infrequent mowing and lack of brushing.

In the final analysis, the production of a superior putting surface is the 

result of judgment, skill, quick recognition of symptoms of trouble, and immediate 
corrective action. The application of sound principles renders the greenkeeping 
superintendent’s position a highly important one.

October, 1947

Timely Turf Topics, 3

SOIL INSECTS CONTROLLED BY CHLORDANE 
John C. Schread *

Chlordane, a new organic insecticide, has shown remarkable results in the 

control of turf insects through rapid killing action and some residual protection.

Ants are serious pests in many types of turf, especially putting greens. 

The miniature brown ant, Lasius niger Linn. van. americanus Emery, which is encountered 
most frequently, builds small single or clustered craters on the surface of turf or 
open soil. This American ant, as well as other ant species, is controlled by Chlordane. 
Two treatments are effective; the spot or individual treatment, and the complete turf 
treatment.

For the individual spot treatment, one-eighth of a teaspoon of 50 percent 

wettable Chlordane powder is placed in the center of each hill and watered thoroughly 
into the nest, using a four-gallon pressure sprayer with the spray nozzle removed, or 
using a watering can with the spreader removed.

For the complete turf treatment, the entire area is impregnated with the 

material. The 50 percent wettable powder applied at the rate of four ounces to 1,000 
squdre feet was found to be desirable from the standpoint of the economic and the 
residual value of the insecticide. Four ounces of Chlordane are agitated in 75 to 100 
gallons of water in a spray rig and applied with a hose and garden nozzle at a pressure 
of 100 pounds over 1,000 square feet. The turf is then watered with 50 to 60 gallons 
of water to 1,000 square feet to obtain maximum penetration. This treatment has 
destroyed all ants and has given complete protection from reinvasion for a period of 
four to six weeks. By treating collars and borders, as well as bunkers and approaches, 
for a radius of 50 feet, reinvasion may be prevented for longer periods.

For Japanese beetle larvae in the soil, Chlordane is quicker acting than are 

DDT, benzene hexachloride, and Toxaphene. Applied to turf on May 20 at 8, 16, and 24 
pounds of actual Chlordane to the acre, the mortality of third instar larvae one month 
later was in the order of 88, 93, and 98 percent, respectively. The population of 
grubs in the checks was 106 to the square foot. Chlordane used in the spring against 
a grub population of 100 to a square foot resulted in no appreciable turf injury whereas 
the turf in the checks was completely destroyed by June. By the end of August the 
average for all three rates of application showed 0.2 grubs to the square foot while in 
the checks it ranged from 35 to 102 grubs to the square foot. Chlordane as 10 percent 
dust, applied August 15 at the rate of 100 pounds to the acre, reduced the grub popula­
tion 93 percent in 14 days. For rapid kill, Chlordane may be relied upon.

It is not known exactly how long the toxic effect of Chlordane may last in 

the soil. However, when it is used in the spring the grub population against which it 
is applied is rendered innocuous within a few weeks, and the residual value of the 
insecticide is not entirely lost by early autumn. It is believed that, under conditions 
of extreme urgency for the control of a heavy grub population in a minimum of time. 
Chlordane may be used with assurance.

Chlordane used at the rate of six pounds of a five percent dust and applied to 

1,000 square feet of turf controls chinch bugs. Application may be made at any time 
that an infestation is recognized or in anticipation of an outbreak.

[Chlordane is manufactured by Julius Hyman Company, Denver, Colorado. Formulations of Chlordane ready for use (50 per­
cent wettable powder, dusts, oil sprays, and miscible sprays) are manufactured by several companies, including U. S. Rubber 
Company, Naugatuck, Connecticut; Dow Chemical Company, Midland, Michigan; Planetary Chemical Company, Creve Coeur, 
Missouri; Chipman Chemical Company, Boundbrook, New Jersey; and Stauffer Chemical Company, 420 Lexington Avenue New 
York 17, New York. Ed.]

♦ Entomologist, Connecticut Agricultural Experiment Station, New Haven, Connecticut.

October, 1947 

Timely Turf Topics, 4