PEANUT DISEASES 281 



Hum blight than are bunch types (22, 92), but many observers feel that 

 this is actually a difference in response to attack resulting from a differ- 

 ence in habit. 



In the United States it is believed that attacks of Sclerotium rolfsii on 

 peanuts are less severe in heavy (92) or poorly aerated land (54). In 

 South Africa it is indicated that well-drained friable soils should be used 

 for peanut culture to reduce losses from Sclerotium blight (64), although 

 the disease has been reported from this region as equally severe on all soil 

 types (22). In Georgia, Sclerotium rolfsii seems less severe on heavier 

 soils, but these soils are not particularly adapted to peanut culture and are 

 usually avoided by peanut growers. Deep plowing, recommended in 

 South Africa for control of Sclerotium blight (22), has not been tho- 

 roughly tested in the United States. 



The number of susceptible crops suggests that it is impractical to 

 eradicate Sclerotium blight by crop rotation (92). It is reported from 

 North Carolina that there appears to be no relationship between previous 

 crops and prevalence of the disease on peanuts (13). In Virginia, how- 

 ever, an apparent correlation has been observed (150). In South Africa 

 it is suggested that peanut fields may be cleared of the fungus by follow- 

 ing peanuts with a grass crop for 2 years, then another legume such as 

 soybeans the third year (22). Also, in South Africa it is thought that 

 virgin soils should be planted to a nonsusceptible crop for a year or two 

 before planting to peanuts (22) . In Texas it is recommended that infested 

 peanut fields be replanted to the apparently resistant varieties of cow- 

 peas (72). In Georgia a preliminary survey indicated that Sclerotium 

 blight is more severe on peanuts following peanut?, cotton or lupine than 

 on peanuts following corn or small grain (52). 



Some soil treatments have been tested for control of Sclerotium blight 

 of peanuts. One test reported no results (92). A report from North Caro- 

 lina in 1938 indicated beneficial results from some inorganic elements 

 added to fertilizer and from sulfur and lime appHcations (111). In 1941, 

 also from North Carolina, some control was reported from heavy appli- 

 cations of copper and sulfur to the surface of the soil in peanut rows dur- 

 ing July and August (101). 



At present, therefore, only general recommendations for control of 

 Sclerotium blight can be made. These include : 



A. Plant good, carefully treated seeds to insure proper stand estab- 

 lishment and initial vigor. 



B. Plant seeds thickly to insure good stands. 



C. Maintain vigor by dusting for leafspof. 



