CARTER: ILLINOIS TREES: THEIR DISEASES 



45 



Fig. 43.— Apple scab develops as small to large olivaceous to sooty spots 

 on leaves. Small young spots are evident on the lower center leaf. Large 

 radiating spots with feathery margins are evident on the upper center leaf. 

 Large definite spots with well-defined margins are evident on the remaining 

 leaves. The lower right leaf has turned yellow because of several elongate 

 lesions on its petiole. 



