Family Leguminosae 265 



half to a million spores are formed on one infected 

 pod alone. The period of incubation usually varies 

 from four to six days. 



In culture media, the growth is at first white, but 

 it soon becomes jet black in color. The mycelium 

 of the fungus is hyaline, small at first, but later be- 

 coming larger and darker. 



Control. Spraying has not given satisfactory 

 results. The best control is to plant clean seed se- 

 lected from clean pods. The latter before shelling 

 may be dipped for ten minutes in a solution of one 

 part of corrosive sublimate to a thousand of water. 

 The treated pods are then dried in the sun, shelled, 

 and the seed put away in dry mason jars until the 

 following spring. Should weevils threaten these 

 seeds, they may be fumigated with carbon bisulphide. 

 By reserving a plot destined for bean seed, by care- 

 fully destroying infected plants, and by selecting 

 clean pods and seed, anthracnose and blight may be 

 kept in check. 



Under no circumstances should an infected field be 

 cultivated in damp weather, or when the dew is still 

 on the plants. When this is done the spores of the 

 fungus are scattered broadcast in the field. As 

 for resistant varieties, there is very little to select 

 from. However, Barrus 1 found that the Wells 

 red kidney bean is most resistant to anthracnose. It 

 is therefore recommended for trial in localities where 

 anthracnose prevails. In selecting for seed resistant 

 varieties, these must of course be artificially inoculated 



1 Barrus, M. F., Phytopath. 5 : 303-311, 1915. 



