Bean. 263 



Treatment. The use of healthy seed is of the greatest impor- 

 tance. Diseased seed may be soaked in some good fungicide, but 

 the value of the operation is open to doubt. Professor Beach 

 has made a careful study of this disease, and his conclusion is 

 as follows : 1 " Even when the treatment of the seed by the best 

 fungicides is so severe that the stand is seriously injured, there 

 remains enough of the disease to injure the crop under field 

 conditions. At the time of harvesting the crop in the above 

 noted experiments, not a sound plant or even a sound pod was 

 found in the whole lot. These results certainly give little en- 

 couragement for hope that treatment of seed w r ith fungicides 

 will yield sufficiently good results to justify recommending its 

 adoption." 



The recommendations made by Professor Beach in regard to 

 treating the disease are : " (1) Selection of sound seed; (2) im- 

 mediate removal of infected seedlings from the field ; (3) keep- 

 ing the foliage covered with Bordeaux mixture." A weaker 

 mixture, one containing about 1.5 per cent of copper sulphate, 

 has given excellent results, and it is harmless to foliage. The 

 disease is more severe in low, damp places, so these should be 

 avoided as much as possible. 



Rust (Uromyces Phaseoli, Winter). Description. Diseased 

 leaves first show small, brown dots which are nearly circular, 

 and slightly elevated. They soon discharge a brown powder, 

 this being the first crop of spores. Later, a second crop of 

 spores is produced; these are black in color, and somewhat 

 larger than the earlier form. The buds are similarly affected. 



Treatment. The free use of Bordeaux mixture may afford 

 full protection to exposed plants, but as yet no general use of 

 the remedy has been made. 



INSECT ENEMIES. 



Bean Weevil (Bruchus obtectus, Say). This insect closely 

 resembles the pea weevil in appearance, and their life histories 

 are practically identical. See under PEA. 



1 Some Sean Diseases. A thesis in the Bot. Dept. of the Agric. Coll. Ames, 

 Iowa, 1892, 323. 



