Exoascus deformans (PEACH LEAF-CURL) l 



A. Classification: 

 Division I. Thallophyta. 



Subdivision B. Fungi. 

 Class IV. Ascomycetes (Sac Fungi) . 

 Order. Protodiscales. 

 Family. Exoascaceae. 

 Genus. Exoascus. 

 Species, deformans (Berk.) Fuckel. 



B. Habitat: 



i. What varieties of peach trees are most affected by 

 this common and frequently destructive disease? 

 Does it deform any other part of the plant than the 

 leaves? How does it injure the tree? 



C. Naked-eye Characters: 



i . What is the character of the diseased tissues ? What 

 color are they? Draw and otherwise compare a 

 healthy and a diseased leaf. Draw also a diseased 

 twig, showing hyper trophied stem. 



D. Microscopic Characters: 



1. Make thin sections of diseased leaves or stems and 

 examine. Draw some of the intercellular mycelium, 

 as well as one or two of the asci. 



2. How many spores in a mature ascus? Is there 

 evidence of yeast-like budding of spores in the 

 ascus? Are there any asexual spores formed? 

 How is the infection spread? 



1 The directions for Exoascus, Microsphaera, and Ustilago (pp. 135- 

 139) were prepared by Dr. E. W. Olive, Brooklyn Botanic Garden. 



