PEANUT DISEASES 305 



excessive accumulations of soil moisture be practiced. There is the possi- 

 bility that one (or both) of the Sclerotinias on peanuts reported from 

 China and Japan is the same as this Sclerotinia reported from Argentina. 



BoTRYTis Late Blight 



Species of Botrytis have been observed associated with some unim- 

 portant diseases of peanuts. Possibly these Botrytis spp. are conidial 

 forms of Sclerotinias but no studies have been made of this aspect. 



Suematu (146) in Japan reported peanuts severely attacked by a 

 Botrytis sp. during persistent wet weather, with the fungus forming 

 conidia on stems and pods. Attacked pods did not mature and were 

 later covered with dark sclerotia. Successful inoculation tests were re- 

 ported. 



Typical Botrytis late blight of peanuts has been observed by B. B. 

 Higgins in Georgia ^^. Noted on mature or overmature peanuts, the in- 

 fection develops during cool damp days of early fall. Growing tips were 

 attacked and covered with a grey spore mass. Sclerotia were formed on 

 pegs and pods, a few of which were partially to completely decayed. 



It would appear that the parasitism of Botrytis sp. on peanuts may 

 be dependent upon damp cool weather. Control methods include planting 

 practices to avoid maturation during such weather. 



Ashy Stem Blight and Diplodia Blight 



In the southeastern United States older peanut plants killed by Sclero- 

 tium roljsii, insects, etc. are soon overgrown by fungi. Many living plants 

 approaching maturity are similarly overgrown, particularly those partially 

 defoliated by leaf spot or insects. Examination usually shows that these 

 fungal structures are sclerotia of Sclerotium bataticola Taub., pycnidia of 

 Macrophomina phaseoli (Maubl.) Ashby, and pycnidia of a Diplodia 



sp- 



Ashy stem blight. The sclerotia of Sclerotium bataticola and pycnidia 

 of Macrophomina phaseoli on peanuts give the stems an "ashy" appear- 

 ance. The structures are regarded as stages of the same fungus, and this 

 has been demonstrated with isolations from plants other than peanuts 

 (83). 



Most references to Sclerotium bataticola on peanuts are primarily 

 concerned with the seedling disease "charcoal rot"^*- Observations on a 

 variety of plants indicate that ashy stem blight results from invasion of 



13 Unpublished observations. 



" See previous section on charcoal rot, page 267; also section on concealed damage, pp. 284-288 

 for another aspect of i'. bataticola on peanuts. 



