PEANUT DISEASES 267 



to typical damping-off fungi. When such fungi are mentioned they are 

 given a relatively minor position (97, 123). 



Control. Damping-off must be regarded as a minor factor contributing 

 to poor stands of peanuts. The use of treated seeds and close spacing to 

 insure replacements for plants killed by damping-off constitute the only 

 recommended control measures at present. The general prevalence of 

 such practices probably accounts for the inf requency with which damping- 

 off is observed. 



Seedling Dry Rots 



Importance. Young peanut seedlings are subject to a type of rot 

 distinct from damping-off and known as "dry rot" (63). The fungi ap- 

 parently associated with most seedling dry rots in southeastern United 

 States a,re Sclerotium bataticola Taub. (the "charcoal rot" organism) 

 and Rhizoctonia solani Kuhn. Reports on peanut diseases have shown that 

 these fungi are widespread in the United States {77, 78, 87, 101, 111, 

 119, 123, 126, 157) and elsewhere (26, 115, 147, 152). In North Caro- 

 lina each of these organisms accounted for about 35 percent of the total 

 isolations from diseased peanut tissue (101). S. bataticola has been called 

 "a major pathological and economic problem" on various crops including 

 peanuts in southern United States (63), and reports on peanuts from 

 India (147, 152) and Palestine (115) have similarly evaluated this 

 organism. There are possibly other types of seedling dry rots as yet not 

 recognized as distinct. For example, an early stage of Fusarium wilt^ 

 reported from the southeastern United States (74, 92) and other regions 

 (80, 115) may sometimes be confused with seedling dry rots. 



Most reports do not distinguish between seedling dry rots and the 

 attacks of the same causal organisms on more mature plants. It has been 

 noted that 5". bataticola attacks peanuts principally in the seedling stage 

 (63, 152) but some observations may have been of the "ashy stem blight" 

 on mature plants.^ Observations in southeastern United States tend to 

 indicate that R. solani rarely infects mature peanut plants^ and then 

 generally affects only single branches, but some of these reports may 

 have included attacks on mature plants. On this basis, therefore, seedling 

 dry rots are best regarded as of intermediate importance in relation to de- 

 velopment of peanut stands. 



Description. Charcoal rot is easily recognized. The first symptoms 

 are greenish-grey watery necrotic areas on stems just at the soil surface. 



2 See page 303 for discussion of Fusarium wilt. 



' See page 305 for discussion of "ashy stem blight," and R. solani on mature peanut plants. 



