Bean Anthracnose. 297 



ern States, on liis irrigated land, and grow a crop perfectly free from 

 the parasite. He accompanied his statement with about a quart of 

 Warden's Kidney Wax beans, which he had grown on his irrigated 

 lands during the season of 1906. Careful germination tests were made 

 of this seed and no evidence of the anthracnose was to be discovered. 

 The seed was planted during the season of 1907 on an isolated plot of 

 land on the University Farm. At the same time on another plot of 

 land about a quarter of a mile distant was planted seed of the Davis 

 White Wax and Refugee Green Pod, both of which showed by germina- 

 tion test, a large percentage of diseased seed. The Wardell Kidney Wax 

 from the irrigated lands gave a crop entirely free from the anthracnose 

 except for one plant. This plant was at the end of the patch, along 

 which ran a foot path leading directly from a house across the road 

 into the University farm opposite. x\s there was a garden with diseased 

 beans at the house across the way, it seemed very probable that the 

 infection was carried in by some person passing through this diseased 

 patch and along this pathway. All of the plants in the immediate neigh- 

 borhood of the infected one were carefully examined, but absolutely 

 no trace of the disease was to be found on any of them. This plant was 

 removed and destroyed. The diseased seed planted in the plot a quarter 

 of a mile away gave a crop that was very generally affected with the 

 anthracnose, and this bear in mind, during the season of 1907, when 

 weather conditions were very unfavorable to the development of the 

 disease. These observations and experiences convince the writer that 

 here is the most promising suggestion for a practical and effective 

 method of controlling the disease. It seems evident, first, that the 

 disease is carried over entirely in the seed; second, that the disease is 

 not ordinarily carried for any considerable distance by natural agents, 

 such as rain, wind, etc.; third, that if perfectly clean seed is planted 

 and ordinary precaution taken to prevent the introduction of the disease 

 on tools, or by workmen, a perfectly clean crop can be produced, even 

 in seasons the most favorable to the development of the fungus. 



Methods of obtaining clean seed. — It is first necessary to work out a 

 satisfactory method of obtaining clean seed of the varieties particularly 

 desired in any locality. As has been clearly shown, hand sorting of 

 the seed, after it is has been thrashed from the pods, is a failure, so far as 

 eradicating the anthracnose is concerned. Even if a large percentage 

 of the disease might be eliminated in this way, it would still be in- 

 effective, since in seasons favorable to the disease, a very small percent- 

 age of affected seed might be sufficient to destroy or seriously injure 

 the crop. 



