198 Mortier F. Barrus 



the conidiophores, and these spores break through to the surface as a 

 pasty mass. The fungus is capable of living from one season to another, 

 and even for two seasons, in old affected vines and pods, which may serve 

 as a source of inoculum when carried to the field. Spores washed into 

 the soil are not viable to any extent after seven weeks. 



The fungus when it invades the seed is able to live in its tissues in a 

 more or less inactive condition for at least two years when the conditions 

 of seed storage are not unfavorable for it. 



Plants in the seedling stage and the youngest parts of older plants are 

 the most susceptible to the disease. 



There are at least two strains or biologic forms of the fungus. Many 

 varieties of Phaseolus vulgaris resistant to the one are susceptible to the 

 other, and vice versa. There are some varieties that are very susceptible 

 to both strains, and at least one that is highly resistant to both. The 

 wax-podded bush beans include a larger percentage susceptible to both 

 strains than are found in other groups of varieties. 



Several other species of Phaseolus are susceptible to anthracnose, 

 but in this country, with rare exceptions, the disease is not severe nor 

 often noticeable on such plants. 



A few species of the related genera Vigna (cowpea) and Dolichos (kulthi 

 and val bean) have shown some susceptibility in a few cases, but plants 

 of other genera which have been inoculated have shown complete immunity. 



Varieties of Phaseolus vulgaris are not susceptible to infection by fungi 

 causing anthracnose of other plants, so far as infection experiments on 

 them have been tried. 



Selection of seed from clean pods has given a crop free from anthracnose 

 in nearly all cases, and has always given anthracnose-free seedlings in 

 clean soil. 



Western-grown bean seed gave crops free from anthracnose but with 

 considerable blight. 



Spraying with bordeaux mixture throughout the season has prevented 

 anthracnose to a large extent even in seasons favorable for it. In dry 

 seasons spraying does not increase the yield. Applications of lime-sulfur 

 solution and of two prepared fungicides gave some control, but not as 

 good control as did bordeaux mixture. 



The use of resistant varieties gave greatest promise of a satisfactory 

 means of control. 



