16 DISEASES OF CROPS. 



months the crop in this district has been a failure. Not 

 having seen anything like it before, I thought it would be 

 interesting for j'ou to see them." The author found that 

 these " boils " were caused by the growth of a parasitic 

 fungus within the root, etc., of the bean plant {Chemical 

 News, vol. 56, p. 84 ; Lincoln Gazette, June 4th, 1887). 

 A complete study of the life-history of the bean-root 

 fungus has been made by Professor H. M. Ward, E.R.S. 

 (Philosophical Transactions of the Royal Society, 1887). 



Prevention. — Avoid sowing maggot-eaten seeds or seeds 

 from infested crops. Such seeds cannot produce healthy 

 plants. 



Cure. — (1) The author found that iron sulphate com- 

 pletely destroyed the spores, hyphae, and myceUa of this 

 fungus {Chemical News, vol. 56, p. 84). The iron sul- 

 phate should be used as a top-dressing (| cwt. to the acre), 

 either mixed with sand or dry soil, or alone, when the 

 young plants are just above ground. (2) After the seed- 

 bed has been prepared, water it with a solution of iron 

 sulphate (from I to 1 lb. of iron sulphate per gallon of 

 water). This wiU destroy any fungoid spores that may 

 be in the soil. 



"Bean Brand" (Pwcctma /a&ce) occurs about August 

 or September. It produces no spots on the bean plant, but 

 its sori (masses of spores) are surrounded by a ruptured 

 epidermis. The spores are black. 



The Bean Mildew {Erysiphe Martii). For a 

 description of this parasitic fungus see later in this 

 chapter, under the heading of " Pea Mildew." The Bean 

 Mildew attacks beans, peas, and other plants. 



(2) The Pakasites of Clovees. 

 The Clover Weevils. These small beetles devour 



