LEGUMINOUS CROPS. 29 



The formation of mycelia and spores constitutes the first 

 stage of the life-history of the pea mildew. 



Later, and under favourable circumstances, the mycelia 

 produce a number of globose bodies (the conceptacles or 

 perithecia) of a brown colour. Under the higher powers 

 of the microscope the conceptacles are similar in appear- 

 ance to rig. 9 B. Within each conceptacle there are a 

 number of oval-shaped bodies (asci) containing spores (see 

 Mg. 9, C and D). After a time these conceptacles fall to 

 the ground and hibernate until the following spring or 

 early summer. Then they burst, and the spores are set 

 free, to be wafted about by air-currents, until they fall 

 upon a suitable medium for germination to take place. 

 These spores produce the mycelium of .the first stage of 

 the life-history of this fungus. 



Erysiphe Martii causes immature decay, besides seriously 

 interfering with the processes of transpiration and assimila- 

 tion, and thereby prevents the growth of the host-plant. 

 This fungus attacks beans, melilot, peas, and other plants. 



Prevention. — (1) Destroy all infested matter from the 

 previous year's crops. (2) Clear away weeds, and destroy 

 them by fire. (3) As the fungus has been seen growing 

 inside the pods of peas, steep the seed peas before sowing 

 in a solution of iron sulphate (1 lb. of iron sulphate to a 

 gallon of water). This will destroy the conceptacles and 

 spores of the fungus. 



The Pea Mould (Peronospora vicice, Fig. 10) is 

 the fungus which causes brown spots on the leaves of 

 the pea-plant and other legumes. " Damp, close weather 

 favours the extension of this fungus, and dry weather 

 retards its growth." The life-history of P. vicice is 

 similar to that of the clover mildew already described. 

 Like all the Peronosporece, it grows internally in living 



