Bean Anthracnose 167 



treatment materially reduced the percentage of germination. Muncie 

 states, in summing up the results of the treatments, that it seems possible 

 to control the disease in a large degree in case of a light infection by 

 employing seed treatments, and that the treatment most efficient is 

 either a thirty-minutes immersion in a 35-per-cent solution of bleaching 

 powder, or a sprinkling of the seed, as in the treatment of oat smut, with 

 a solution of formaldehyde, using 1 pint of formaldehyde to 30 gallons 

 of water. There is not sufficient evidence submitted in his data, however, 

 to admit this possibility. His summary at the end of the bulletin states 

 accurately the conclusions reached, namely, " Seed treatments with 

 chemical solutions and wet and dry heat have failed to control these 

 diseases." Rapp (1920) concludes from his numerous seed-treatment 

 experiments with formaldehyde, mercuric chloride, sulfuric acid, dry heat, 

 and hot water, to control bacterial blight, that no present method can be 

 regarded as satisfactory, since in killing the blight pathogene the germinating 

 power of the seed is either greatly weakened or totally destroyed. 



Kick! and West (1918) soaked bean and other seeds for varying lengths 

 of time (from six to seventy-two hours), and found that, while germination 

 was more rapid from soaked than from unsoaked seeds, subsequent 

 growth, particularly of the bean, was poorer — although with horse beans 

 (Yicia faba) it was greatly improved. Bean seed was soaked in water 

 at various temperatures, but always the resultant growth was poorer than 

 when dry seed was used. The literature on the subject, however, reviewed 

 by Kidd and West (1919), indicates a better growth and a higher total 

 yield from soaking in a limited quantity of water. 



Further experimentation with seed treatment should not be regarded 

 as something bound to be resultless. No one has made a careful study 

 of the permeability of the seed coat of the bean to various disinfecting 

 agencies, nor of the action of these agencies on the fungus within the 

 seed. Seed treatment, to be effective, must destroy the pathogene within 

 the seed, notwithstanding the extent of its growth there, in order that 

 the affected seed may not serve as a source of inoculum. At the same 

 time, the treatment must not injure sound seed. Any treatment, to be 

 of value, must achieve these two conditions, and the problem does not 

 appear to be insurmountable. Nevertheless, healthy seed can be obtained 

 in other ways. The selection of clean seed (page 168) certainly offers a 

 greater promise of success. 



