PEANUT DISEASES 



273 



At maturity early leafspots are reddish-brown to black, and lighter brown 

 to tan with less distinct halos on the lower surface. Late leafspots are 

 soon very dark brown to almost black on both surfaces. 



Cushions of conidiophores are formed at first only on the upper sur- 

 face in early leafspot, but sometimes form on the lower surfaces of older 

 spots. In late leafspot, however, conidiophores are almost always confined 

 to the lower leaf surfaces, and the cushions of tufts usually are in plainly 

 visible concentric circles. When the conidiophore cushion of late leafspot 

 becomes amphigenous with age, this concentric marking remains plainly 

 evident (68). 



Both leafspots are distinctly necrotic at maturity. The spots are 

 circular, or irregular, and often coalescing. Sizes range from 1 mm. to 

 over 1 cm. in diameter (68). Spots on stems, petioles, pegs and pods are 

 similar, but more frequently are irregular or eliptical in shape. In early 

 leafspot the petioles and stem lesions develop later in the season than do 

 those on the leaves (171). These symptoms are shown in figure 1. 



Apparently control measures so effectively prevent premature leaf 

 shedding (68, 171) that few observations have been made on defoliation 







r*.. 





Courtesy Alabama Agricultural Experiment Station. 



Figure 1. Cercospora leafspot on leaves of runner peanuts. The spots with the 



halos on the leaf at the left are old lesions caused by Cercospora arachidicola. 

 The dark spots on the leaf at the right are young lesions caused by Cercospora 

 personata. 



