Green World

AN INDUSTRYWIDE PUBLICATION OF THE NEW JERSEY TURFGRASS ASSOCIATION

Volume 2, Number 2 

Systemic Fungicides For
Turfgrass Diseases

Philip M. Halisky

May, 1972

WHERE WILL THEY BE IN ’73?

Systemic fungicides are a new group 
of chemicals that work from inside as 
well as from outside the plant to con­
trol fungus diseases. Because of their 
ability to penetrate, the systemics have 
been shown to be effective against many 
fungal pathogens that are established 
inside plants and therefore “hidden” 
from standard protectant fungicides. 
Virtually all fungi that actively para­
sitize turfgrasses do so by first pen­
etrating susceptible plants during the 
infection process. Once fungal struc­
tures are established within the plant 
they are less vulnerable to protective 
chemical action from a fungicide ap­
plied externally, unless that fungicide 
also enters the plant.

Systemic fungicides may be defined 
as compounds that are absorbed by 
the plant, translocated within the plant, 
and stored within for a limited period 
of time. The use of systemic fungicides 
eliminates the problems of visible spray 
residues, rain wash-off, growth of new 
unprotected grass tillers, and most im­
portantly, the need for repeated, ac­
curately-timed applications common 
with foliar protectants. In contrast, the 
need for frequent applications of pro­
tectant fungicides results in high labor 
costs — an obvious disadvantage in 
any turf management program.

Considering the needs of the turf­
grass industry in combatting diseases, 
it seems appropriate to emphasize the 
merits of systemic fungicides when 
compared with protectant chemicals. 
In addition to the advantages discussed 
above, the desirable characteristics of 
systemic fungicides are as follows:

a)  They are effective at low dosages 

(1-2 oz/M2).

b)  They have long residual activity 

(persistence).

c)  They show broad spectrum ac­
tivity. against several fungal 
pathogens of turf.

d)  Most do not injure the turf, they 

are relatively non-phytotoxic.

Currently, several systemic fungi­
cides are being widely evaluated for 
usage against turf diseases. Most of 
those available commercially or under

These familiar turf research plots on College Road at Rutgers are soon to be 
lost to the bulldozer in preparation for programmed school “progress.” The 
New Jersey Turfgrass Association has expressed its serious concern regarding 
the future of effective turfgrass research in New Jersey. In this period of 
environmental concern it seems ironic that established basic turf research is 
to be plowed under without adequate consideration for the future.

evaluation as “experimental com­
pounds” are listed below.

a)  Thiobendazole compounds (Mer- 

tect HOF & Tobaz).

b)  Thiophanate derivatives (Topsin 

M & Cleary 3336).

c)  Benzimidazole derivatives (Ter- 

san 1991).

d)  Oxathiin compounds (Plantvax 

& Vitavax).

e)  Triarimol (EL-273 Experiment­

al Compound).

From a chemical standpoint, the 
Benzimidazole (Tersan 1991) and 
Thiobendazole (Mertect and Tobaz) 
compounds are structurally related. 
The remaining systemics are no re- 
lated chemically. However, the fungi- 
toxic derivatives or “break-down prod- 
ucts” that are formed inside the plant

after application of benzimidazole, thi­
obendazole, or thiophanate fungicides 
appear to be metabolically related.

In conclusion, each systemic fungi­
cide appears to be a distinct chemical 
compound that should be evaluated 
for its own merits with respect to fun­
gicidal effectiveness, phytotoxicity, 
spectrum of activity, residual qualities, 
turf color and turf density. However, 
the mode-of-action of these chemicals 
within the grass plant appear to be 
metabolically similar.

Reference

von Rumker, R., T. Parr, C. A. Ander­
son, J. W. Young, and J. Hensel. 
1965. SYSTEMICS, Parts 1 (Sep­
tember), 2 (October), 3 (Novem­
ber), 4 (December); FARM 
CHEMICALS. (Contribution from 
Chemagro Corporation).

Results of Systemic
Fungicide Survey

R. E. Engel, P. M. Halisky, 

and C. W. Bussey

The turfgrass industry has always 
had need for new and better fungicides. 
Recently the reservations or restric­
tions on mercury and cadmium fungi­
cides have reduced the choice of types. 
The mercuries have been used for 
many decades. In cases where they 
gave something less than excellent con­
trol they offered compensation by giv­
ing some protection against most dis­
eases that might appear unexpectedly. 
Assorted new chemicals have appeared 
in recent years. Now the systemics 
have added a new dimension. The ex­
perience gained with the systemics that 
have been on the market briefly should 
give some insight to the changing scene. 
As with all new turfgrass fungicides, it 
is important to determine their strength 
and weaknesses.

Questionnaires on use of systemic 
fungicides in 1971 were sent to 200 
golf course superintendents in the area 
of southern New Jersey-Philadelphia 
through the northern New Jersey-New 
York City Metropolitan area. A total 
of 68 replies were returned. Fifty- 
seven of these reported using systemic 
fungicides as follows: 57 reports on 
Tersan 1991, 16 reports on Cleary 
3336, and 2 reports on Mallinckrodt 
Tobaz. The number of reports should 
not be construed as an indication of 
desirability, as these fungicides are new 
on the market. The comments are con­
fined to dollarspot and large brown- 
patch, as reports on other diseases were 
too few to determine any trends.

Summary — Reports of Systemic 
Fungicides Used on Greens 
and Fairways
Part I — Reports on Tersan 1991: 49 
of the reports were from superintend­
ents who used Tersan 1991 fungicide.
A.  Results with Dollarspot — Thir­
teen of 47 users on greens reported no 
dollarspot present and 32 reported 
none at the start of T-1991 treatments. 
All reported good to excellent control 
of this disease. Of 23 users of this 
systemic on fairways, 4 reported dol­
larspot at the time of treatment. Only 
1 reported less than good control after 
treatment of fairways.

B.  Large Brownpatch Control — 
Ten T-1991 users reported large 
brownpatch on greens prior to use. 
Eight of these reported good control, 1 
reported fair control, and 1 reported 
poor control. Five of the users report­
ed that large brownpatch occurred on 
greens within 10 days after treatment. 
On fairways, 4 of 23 users reported 
large brownpatch within 10 days after 
use.

Part II — Reports on Cleary 3336

A.  Dollarspot Control — Of 11 
users on greens, all but 1 reported good 
or better control (1 fair). Three of 5 
users on fairways reported dollarspot 
present at start of treatment with ex­
cellent control.

B.  Large Brownpatch Control — 
Two of the C-3336 users reported 
large brownpatch on greens with fair 
to poor control. On fairways, 2 users 
reported large brownpatch after using 
C-3336 with fair control. One report­
ed this disease before and after with 
fair to good control.
Part III — Reports on Tobaz: Two 
users reported use of this material. It 
received ratings of good and poor on 
dollarspot. Both reported large brown­
patch within 10 days after use.

Summary of Attitudes from 

Users Reporting

Would rate as a good 
to very good fungicide

Tersan 1991 
Cleary 3336 
Tobaz 

(No. of users)

46  of 49
12  of 15
1  of 2

Would use on 

Large

Dollarspot Brownpatch 

(No. of users)
27 
12
1
6 
1
2 

Tersan 1991 
Cleary 3336 
Tobaz 

In general, the responding super­
intendents expressed considerable en­
thusiasm in summarizing their experi­
ences with systemic fungicides. The 
very good control of dollarspot for ex­
tended periods of time was an out­
standing feature of the reports. How­
ever, it appears that the systemics may 
have a weakness in failing to control 
large brownpatch. A wide margin of 
safety, good residual qualities, and sub­
stantial savings in labor dollars were 
cited as major “plus” factors. Although 
many superintendents recognized that 
the systemics were not “cure-all fungi­
cides for all diseases,” nonetheless they 
felt that these chemicals constituted a 
breakthrough in the turf fungicide in­
dustry and were definitely “here-to- 
stay.”

Comments on Fungicides Used

“A breakthrough in the turf fungi­
cide industry. Extended control will 
save valuable man-hours.”

“No disease with 1991 on greens 
but we were plagued with large brown­
patch where 1991 was used on tees at 
same rate of application as on greens.”
“Like to alternate Tersan 1991 with 

other fungicides.”

“More than satisfied with the results 
of C-3336, especially time and labor 
saved in applications of other materials 
used in past.”

“Nine fairways sprayed with C-3336 
have 40-50% less large brownpatch 
disease than those with T-1991 appli­
cation.”

“Systemics are here to stay — excel­
lent on ‘bent-poa’ fairways especially 
— alone, systemics are not expected to 
be a cure-all.”

“There are no signs of disease now 
(December) on the treated (C-3336) 
greens. The last application was on 
Sept. 20, 1971.”

“I had Fusarium roseum on my 
Merion; 1991 proved to be effective at 
the 2-oz rate.”

“One-oz of Tersan 1991 was as 
good as 2-oz and greens have better 
color.”

“I feel that the listed systemics are 
probably going to be used by 90% of 
the superintendents in the coming years 
as they save labor, prevent the disease, 
and are safe to apply.”

“Sprayed tees at 3-week intervals 

instead of 1-week as in past.”

“On 7/29/71, 18 greens were treat­
ed with 1991 and 18 greens with To­
baz. The same evening a 1.09" rain­
fall was recorded. The following week 
was exceptionally humid, wet and 
warm. The 18 greens treated with 
Tobaz experienced a severe infection 
of brownpatch. In contrast the 18 
greens treated with 1991 had none.”

Acknowledgments

The authors wish to express their 
sincere appreciation to those golf su­
perintendents who took the time to re­
spond to our questionnaire on systemic 
fungicides. You are to be commended 
for your willingness to share your views 
and experiences with your fellow super­
intendents and other turfgrass profes­
sionals reading this issue of the 
GREEN WORLD.

Lawn Diseases and Their Control

Anthony Grasso

A frequently asked question of pro­
fessional landscape gardeners and gar­
den supply dealers is, “What should I 
do about diseases on my lawn?” Con­
cern for lawn disease control is good, 
but the answer is complex.

Small dead spots are a common 
phenomenon in late spring or during 
the summer. While many of these are 
caused by oil or gas spills from the 
mower, dog injury, insect damage or 
fertilizer spillage, disease is a major 
offender. If it is a disease, then by all 
means it is usually worth the time and 
expense to cure it or prevent it. Select­
ing grasses that are adapted to local 
climate, light conditions and soil types 
is usually the first line of defense 
against lawn diseases. Proper lawn 
care such as fertilizing, watering, mow­
ing, insect and weed control are equal­
ly important. If heavy rates of fertilizer 
are used early in order to take advan­
tage of the spring rains on common

Kentucky bluegrass, look for an out­
break of leaf spot, usually about the 
middle of May. If there is overuse of 
fertilizer in the spring, by summer we 
can look forward to Fusarium roseum 
and large brownpatch. On the other 
hand, too little fertilizer encourages 
dollarspot. Emphasis on September 
and October fertilization is better on 
many lawns.

Before attempting the control of 
diseases, proper diagnosis of the lawn 
problem is very important. One way 
to tell if it’s a disease is to check the 
blades of grass. Diseased grass usually 
shows some disfigurement. Dark mar­
gins, straw colored spots, shriveling 
blades or dark blotches of one sort or 
another. Whereas if the damage is 
from insects, the blades of grass have 
a chewed effect or a ragged look. The 
experienced man often recognizes sev­
eral of the diseases by general appear­
ance. In some cases microscopic ex­
amination is necessary. The most com­
mon diseases found in the appearance 
area are Helminthosporium leaf spot, 
dollarspot, some brownpatch, stripe 
smut, and Fusarium blight.
Leaf Spot

This fungus produces reddish brown 
to purplish black spots on leaves and 
stems of Kentucky bluegrass. Leaves 
usually shrivel and when the disease 
is severe, the stems, crowns and rhi­
zomes usually rot. This disease is most 
active in mid- to late-spring.

Control — This disease can be con­
trolled by growing resistant varieties of 
grass, such as Merion, Fylking, Penn- 
star, and Baron as compared with the 
common Kentucky bluegrass types. 
Dollarspot

This disease usually appears as the 
name indicates — small, light colored 
brown spots the size of a silver dollar. 
The fungus usually is most active dur­
ing cool wet weather of late spring and 
early fall. Damage is usually greatest 
when there is a deficiency of nitrogen. 
When this disease is growing actively, 
a white cobweb mycelium can be seen 
when the dew is still on the grass. Many 
times the upper grass blades are af­
fected by light brown blotches across 
the blade.

Control — Be sure that nitrogen 
rates are adequate. The use of systemic 
fungicides during early spring and 
early fall can be valuable on lawns that 
have a history of trouble from this 
disease.
Brownpatch

This disease occurs during warm 
wet weather, but usually it does most 
damage following a heavy application 
of nitrogen fertilizer. The disease 
spreads by mycelium or by fungus 
threads and gives assorted size patches 
with a smoky outer ring. It usually

disappears during cool, dry weather. 
However, the diseased areas have been 
known to recover with just a change in 
temperature.

Control — Avoid heavy use of ni­
trogen fertilizer. When watering lawns, 
be sure the grass blades have time to 
dry before night.
Stripe Smut

This disease is a problem on the 
widely used Merion Kentucky blue­
grass strain. This is a systemic type 
disease and usually the infected plants 
remain diseased until completely de­
stroyed. The diseased blades develop 
a stringy, shredded appearance and 
when the grass is wiped with a white 
cloth, a black powdery stain will show. 
This sign is most apparent in mid- to 
late-spring.
The Case for Fungicides

While most lawns are not destroyed 
by diseases, the damage caused by dis­
ease is a major cause of unattractive­
ness and weed encroachment. I would 
urge that good management should be 
a major method of attacking disease 
at all times. Also, it is my opinion that 
a greater number of our better lawns 
should have a fungicide program. An 
assortment of improved fungicides is 
available.

Timely Reminders

Dr. Henry W. Indyk
Spring Lawn Establishment —

Spring is the second best period for 
establishing new lawns or other turf- 
grass areas from seed. Spring, as con­
trasted to late summer-early fall, seed­
ings generally have a more difficult 
time in becoming successfully estab­
lished. The young seedlings must 
struggle against the competition of 
weeds, particularly crabgrass and high 
temperature conditions.

Chances of success with spring seed­
ings can be greatly increased. Earli­
ness — as soon as soil and weather 
conditions permit — is very critical. 
Attempts to successfully establish a 
new lawn after May 1 become very 
difficult. However, all is not lost — 
sodding is a technique that can be ef­
fectively used at any season of the 
year providing the soil can be prepared 
and water is available.

An important aid for spring seedings 
is a light mulching. Salt hay is one of 
the best materials to use. For best re­
sults, the mulch should be applied 
lightly and evenly and not removed. 
Light application can be best described 
by applying it so thinly that the soil is 
visible through the mulch when you 
look straight down at your toes. Usual­
ly a large bale of salt hay is adequate 
for about 2500 sq. ft.

The inclusion in the seed mix of a 
small percentage (10 to 20 percent) of 
fast germinating turfgrass is another 
useful technique. The recent develop­
ment of the new improved turf-type 
ryegrasses such as the variety Manhat­
tan, greatly improves the chances with 
spring seedings. Their quick germina­
tion and establishment and attractive 
turf quality characteristics as contrast­
ed to the unsightly pasture-type rye­
grasses serves a definite need in spring 
seedings.
Repair Weak Spots —

Turfgrass areas which show evidence 
of damage or thinning need bolstering 
with some repair seeding. Such areas 
were candidates for frost seeding in 
late February or early March if bare 
soil were exposed. Now it is too late 
to take advantage of frost action. 
Areas to be seeded need some prepara­
tion before seed is planted. Generally, 
a dead mat of old grass is covering the 
soil in such areas. Vigorous hand rak­
ing is effective but difficult and pro­
hibitive on large areas. Thatching ma­
chines make the job much easier and 
the results are much better for proper 
germination of the seed. Selection of 
the machine becomes very important 
since many do not prepare the area 
adequately. The best type of thatcher 
is one which has straight rigid (not 
swinging) blades capable of being ad­
justed to penetrate through any dead 
mat that may be present and at least 
1/2 inch into the soil. The same type 
of machine is very effective for de­
thatching a well-established lawn.

Many overseedings on existing turf­
grass are failures due to improper prep­
aration. Seedings made the easy way 
— directly on a dead mat of grass — 
usually are an effort in futility. In 
order for seed to germinate the area 
must be prepared so that when the 
seed is planted, it comes in direct con­
tact with soil.
Pre-emergence Crabgrass Control —

The development of this technique 
with effective and safe herbicides has 
provided a very potent weapon against 
crabgrass. The timely and proper ap­
plication of pre-emergence materials is 
much easier and more effective than 
postemergence treatments. Aside from 
applying the pre-emergence material 
correctly, time of application is very 
closely associated with effectiveness of 
the results. Application before the 
crabgrass germination season begins is 
essential for the highest degree of con­
trol. Although seasonal variations do 
occur, application before May 1 will 
provide assurance of beating early 
germination of crabgrass.
Buying Manhattan Ryegrass —

Manhattan ryegrass has been de­
veloped and proven as a superior varie­
ty of perennial ryegrass. Because of

its superior performance, it is gaining 
wide-spread recognition with increas­
ing demands on available seed. Every 
effort possible was taken to maintain 
the superior characteristics of the vari­
ety by insistence on conformance to 
high standards in seed production. 
One of the stipulations was to produce 
certified seed. Through certification, a 
means was provided for maintaining 
the genetic identity of the variety which 
has proven its superior turf character­
istics and performance.

At present, uncertified Manhattan 
ryegrass seed is beginning to find its 
way into the retail turfgrass seed trade. 
It is possible that the availability of un­
certified seed will increase in the future. 
This is an unfortunate situation since 
unless high standards are maintained in 
seed production, the superiority of the 
variety can be easily destroyed. In 
uncertified Manhattan ryegrass seed, 
the possibility exists that it has been 
contaminated with annual and other 
inferior ryegrass types as well as other 
undesirable grass seeds which would 
detract from its performance as well as 
appearance. As a consequence, the 
many years of effort by the plant breed­
er in the development of the variety, as 
well as the conscientious effort of re­
sponsible seed producers can be wast­
ed. More importantly, the prime losers 
in such a situation are the purchasers 
of the seed.

Your assurance of high quality seed 
that carries the potential of superior 
characteristics of Manhattan ryegrass 
as developed by the breeder is certified 
seed. When purchasing Manhattan 
ryegrass, insist on certified seed.

Response of Turfgrass Diseases to 
Certain Fungicides

(1)  Benomyl stimulates Growth of 
a Basidiomycete on Turf. A. M. Smith, 
B. A. Stynes, and K. J. More. 1970. 
Plant Disease Reporter 54(9): 744- 
775. In New South Wales, a basid­
iomycete developed in bentgrass turf 
that had received treatments of beno­
myl 4 weeks earlier. The grass was 
not infected, but the turf was disfigured 
by the circular patches that contained 
an abundance of mycelium. Isolates 
of the fungus were stimulated by ben­
omyl in culture plates. One applica­
tion of 2 to 4 oz of 50% w.p. per 
1,000 ft2 of turf controlled dollarspot 
for at least 10 weeks.

(2)  Evaluation of Some Chemicals 
for Control of Stripe Smut in Ken­
tucky Bluegrass Turf. Jackson, N. 
1970. Plant Disease Reporter 54(2): 
168-70. In Rhode Island, wettable 
powder formulations of benomyl, chlo- 
roneb, pentachloronitrobenzene (PC- 
NB), 2, 3-dihydro-5-carboxanilido-6- 
methyl-1, 4-oxathiin-4, 4-dioxide, and 
thiabendazole were evaluated for their 
ability to control stripe smut in heavily 
smutted “Merion” Kentucky bluegrass 
turf. Fall application of benomyl sig­
nificantly reduced the number of smut­
ted tillers as measured the following 
spring. Thiabendazole gave varying 
results and the other three materials 
proved ineffective. PCNB and chlo- 
roneb, though not reducing stripe smut, 
afforded good protection against Hel- 
minthosporium leaf spot. Indications 
are that benomyl and thiabendazole 
may encourage Helminthosporium leaf

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spot in “Merion” Kentucky bluegrass 
turf.

Comments: It is gratifying to see 
such very good promise for dollarspot 
and smut control in turf. Again, these 
studies show the need to determine 
whether a fungicide that controls one 
disease is stimulatory toward other 
turfgrass diseases. It does not seem 
likely that fungicides which control one 
disease and stimulate another are com­
mon, but it is important to know the 
specific cases where this does occur.
R.E.

N. J. TURFGRASS 

ASSOCIATION

Don Marshall, President 
Eugene Field, Vice-President 
Ralph Engel, Secretary 
Janet Schernecke, Treasurer

Membership applicants apply to:

P.O. Box 123 

Caldwell, New Jersey 07006

EDITORIAL STAFF 

Ralph E. Engel 
Eugene A. Field

Roy Bossolt

WILFRED

MacDONALD INC.

Turf Maintenance Equipment

For

Golf Courses

Estates/Schools 

Municipal & County Parks

3800 PARK AVENUE 

WEEHAWKEN, N. J. 07087 

(201) 866-1225