306 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Courtesy Georgia Acirievltiiral Evpcrimcnt Station 



Figure 3. — Botrytis late blight on peanuts. 



weakened plants. The organism, while sometimes a vigorous parasite on 

 seedlings, particularly at high temperatures, appears to be primarily a 

 weak parasite on older or mature plants. This parasitism of 5". bataticola 

 has been investigated and the various observations summarized (63). 



In regard to peanuts, the ashy stem blight needs investigation. It is 

 possible that following periods of excessively high temperatures, excessive 

 defoliation, or excessive insect injury it becomes an important disease re- 

 sulting in death or early maturity of many plants. This insect injur)- and 

 defoliations may be prevented to some extent by dusting programs. 



Diplodia blight. DipJodia sp. has been reported frequently on peanuts 

 in the United States (13). It has been shown that Diplodia sp. is fre- 

 quently associated with peanut seed^" and thus ma}' be seed-transmitted 

 (149). A Diplodia sp. is frequently isolated from }'oung peanut plants 

 with collar rot-"^" but pycnidia are generally not found on younger plants. 

 Pycnidia are frequently found on stems of dead or living mature plants ; 

 thus Diplodia blight is distinctly a disease of older plants. Diplodia blight 

 is easily confused with ashy stem blight. Frequently pycnidia of both 



IS See section on "concealed damage," pp. 284-288. 

 ^* See section on "collar rot," page 269. 



