16 DISEASES OF CROPS. 



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

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

 interesting for you 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. 66, 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, r.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, hyphse, and mycelia of this 

 fungus (Chemical Neics, 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 ol 

 water). This will destroy any fungoid spores that may 

 be in the soil. 



"Bean Brand" (Pwccmza /«&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 Parasites of Clovers. 

 The Clover Weevils. These small beetles devour 



