CHAPTER III. 



FUNGOID DISEASES OF LEGUMINOUS PLANTS. 



(Peas, Beans, etc.) 



I. Mildews. — 

 (a) Mildew. 

 (/;) Mildew (false). 

 (c) Mildew (downy). 



(a) Mildeiv{^Erysiphe Martii)} Class : Ascomv- 

 CETE^i ; Order : Perisporiales. 



This fungus attacks various species of Pisuni, 

 Lathyi'us, Vicia, and Trifolmm ; especially to- 

 wards the end of summer, doing considerable harm. 



Symptoms. — First observed as a snow-white 

 covering on the leaves while the latter are still 

 green, later this woolly covering of fungus mycelium 

 turns a dirty grey, and the leaf assumes a pale- 

 yellow sickly colour. 



Cause, — Microscopic examination of a leal with 

 the above symptoms shows that the cause is the 

 presence of the fungus E. Alar Hi (not to be con- 

 fused with false mildew, p. 64). This fungus is 



' This fungus also appears on certain cruciferous plants. 



63 



