rather than to replant. Early defoliation of soybeans is not as serious as hail 

 damage that occurs closer to the reproductive stage when the pods are developing 

 and filling. 



PLANT DISEASES 



CONFUSING YELLOW LEAF BLIGHT WITH SCLB 



Yellow leaf blight can now be found in many Illinois corn fields. Be careful 

 not to confuse it with the southern corn leaf blight. The two diseases have 

 many similarities. 



Plants with Texas, male-sterile cytoplasm are more susceptible to both yellow 

 and southern corn leaf blight than those with normal cytoplasm. The leaf spots 

 caused by the yellow leaf blight are nearly the same size, shape, and color as 

 those produced by the southern corn leaf blight. 



The only sure way to distinguish between these two blights is to check samples 

 under a laboratory microscope for characteristic spores or fruiting bodies. 



Yellow leaf blight spreads more slowly than southern corn leaf blight, and does 

 so primarily by splashing raindrops that propel the sticky, yellow leaf blight 

 spores onto other plants. The southern corn leaf blight spores are carried in 

 the air. 



Yellow leaf blight is more likely to occur in fields where corn was grown last 

 year. Individual, infected fields may be scattered throughout an area. 



The fungicides cleared for use against eyespot and southern corn leaf blight 

 may be applied to check yellow leaf blight. See Report on Plant Diseases No. 

 204 for details. This publication is available from the Department of Plant 

 Pathology, 218 Mumford Hall, Urbana, Illinois 61801. 



SCLB INFECTION AFTER SHELLING 



At least ten of the reported cases of southern corn leaf blight in Illinois have 

 come from areas where shelling or crib cleaning had been done, and often just be- 

 fore rainy periods. Under such conditions, even normal (N) cytoplasm corn will 

 develop lesions. Fortunately, normal corn is resistant to the southern corn leaf 

 blight fungus. Therefore, the infection does not spread readily and the lesions 

 remain small. Infected leaves that stayed dry in silage may also be a source of 

 disease-causing spores. 



UNUSUAL PROBLEMS WITH IMPORTED SEED 



Unusual diseases or physiological disorders on leaves of corn imported for plant- 

 ing in Illinois may appear under conditions of stress. Farmers should check their 

 fields and record special problems. We know relatively little about disease re- 

 actions and the other agronomic properties of many imported varieties. 



SPRAYING FOR BLIGHT 



Whether or not to spray for southern corn leaf blight is an individual decision 

 that each producer must make about each of his fields . There is no great amount 

 of evidence to suggest that fungicide will be any more effective this year than 

 in 1970. Last year, most fungicide applications were made too late, when the corn 

 was already heavily infected. 



