leaves begin to curl and dry, apply a spray using 2 teaspoons of a 50- to 57- 

 percent malathion or a 25-percent diazinon liquid concentrate per gallon of wa- 

 ter. Do not use malathion on African violets or canaert red cedar. Do not use 

 diazinon on ferns or hibiscus plants. 



PLANT DISEASES 

 SOUTHERN CORN LEAF BLIGHT 



Confirmed cases of the blight have now been recorded in twenty-nine Illinois coun- 

 ties. This development was quite unexpected. If the weather remains warm and dew 

 and rainfall proide adequate moisture, changes in the near future could be even 

 more dramatic. 



During the past week, probably because of the warm weather and the presence of 

 adequate moisture, there were major changes in southern Illinois corn fields. Af- 

 ter checking fields in Macon, Effingham, and Shelby Counties, plant pathologists 

 reported two significant changes: 



1. The blight is spreading from volunteer corn to fields planted with T cytoplasm 

 or blended seed. 



2. The blight is moving from the lower to the upper leaves of the corn plants. 



These changes are most obvious in the southern half of the state, particularly 

 in the southern quarter. 



Farmers should check fields of T cytoplasm and blended corn closely. If there 

 are blight lesions on the upper leaves, a close and continuing check should be 

 made of the conditions in all such fields. Where lesions are evident on the 

 upper leaves, the farmer will have to decide whether or not to plow under the 

 corn and replant with soybeans or sorghum. 



WHEAT 



Scab or head blight . This can now be found in thousands of Illinois wheat fields, 

 as a result of the widespread rains and the warm, humid weather last week. The 

 scab is appearing as a bleached, light-straw color on the wheat heads. They should 

 still be the normal green in most fields. A salmon-pink color may also be evident 

 at the base of the glumes. If the weather stays warm and moist, the spikelets on 

 early infected heads will become speckled with the black, spore-producing bodies 

 of the scab fungus by harvest time. Scab- infested kernels appear to be somewhat 

 shrunken and lightweight, with a flaky- to- scabby appearance. The color ranges 

 from light brown to pink or grayish-white, depending on the time of infection and 

 the weather conditions. 



The same fungus infects other small grains, corn, and forage grasses. It may pro- 

 duce a seedling blight, stalk or ear rot, root rot, crown or foot rot, and stem 

 blight. For details, check Report on Plant Diseases No. 103, "Scab of Cereals," 

 which is available from the Department of Plant Pathology, 218 Mumford Hall, Ur- 

 bana, Illinois 61801. 



Blackening . This is now common on the culms and glumes of certain wheat varieties 

 such as Ben Hur. There is no organism or infection involved. Neither the grain 



