PLANT DISEASES 



LAWN GRASS DISEASES 



I 



Helminthosporium leaf spot disease has been the most common disease problem on sev- 

 eral home- lawn turf specimens received at the University of Illinois plant disease 

 clinic this spring. The predominantly cool wet spring has favored this fungus -cause- 

 disease on bluegrasses, ryegrasses, fescues, and various pasture and wild grasses. 



Helminthosporium leaf spot first appears as small, dark-brown lesions with purple or 

 purplish-red margins. The centers of these spots fade to an ash-white to light-browi 

 or straw color (eyespot) . Under favorable conditions, the spots increase in size 

 rapidly. Two or more lesions may merge and girdle the leaf, causing the death of thi 

 leaf blade. Girdling and the subsequent death of many leaf blades may result in a 

 gradual browning or thinning of some lawns. 



Recommended cultural - control practices for use against Helminthosporium diseases : 



1. Grow locally -adapted, top-quality, disease-free seed or sod (Warren's A-20, A- 34 

 Anheuser Dwarf, Fylking, Merion, Pennstar, etc.) , 



2. Apply N, P, and K according to local recommendations and soil tests. 



3. Mow frequently at the height recommended for your area and the type of grass. i 



4. Increase light penetration and air movement, to help dry-out the grass quicker. ; 



5. Remove excess thatch. 



For chemical control , consider the following herbicides. Suggested rates are given, 

 but be sure to READ AND FOLLOW LABEL INSTRUCTIONS: 



For further information, contact the Department of Plant Pathology, 218 Mumford Hall 

 Urbana, Illinois 61801. Request Report on Plant Diseases No. 400, "Recommendations 

 for the Control of Diseases of Turfgrasses," and RPD No. 405, "Helminthosporium Leaf 

 Crown, and Root Disease of Lawn Grasses." 



EQUIPMENT 



NOZZLES FOR LIQUID HERBICIDE APPLICATION 



Regular, flat-fan or flooding flat-fan nozzle tips are recommended when applying her 

 bicides in liquid form. 



Regular, flat-fan nozzles with a 25-percent overlap by adjacent nozzles will give th< 

 most uniform coverage for broadcasting pesticides. When applying herbicides, operati 

 flat-fan nozzles at a pressure of 20 and 30 pounds per square inch, but never at mon 

 than 40 p.s.i. This avoids the chance of drift. The greater the pressure, the sma^ 

 er the spray particles and the more the drift. Space regular flat-fan nozzles no mon 

 than 20 inches apart on the boom. 



