Bean Anthracnose 107 



bulletin (page 13 of reference cited) gives the loss during 1917 for New 

 York as 5 per cent, or 83,000 bushels, and for the United States as 1.76 

 per cent, or 363,000 bushels. 



The losses from bean anthracnose are due to poor germination of affected 

 seed, to destruction of affected seedlings, to low yield of affected plants, 

 and to decreased value of the product. The principal loss in the production 

 of green beans is due to the spotting of the pods, which renders them 

 unsalable as snap beans and unfit for canning. Southern-grown beans, 

 apparently healthy when shipped, frequently reach northern markets 

 in a badly spotted condition, and if the disease is common in the field, 

 pods kept over night after picking are likely to be rusted the next morning. 

 The lesion may extend through the pod to the seed, discoloring it. The 

 value of dry seed thus affected is lessened, and the buyer usually deducts 

 a certain percentage, the "pick," from the total weight to allow for this 

 depreciation. A poor stand often results from the planting of spotted 

 seeds, many of which fail to germinate, and this result is augmented by 

 the destruction of seedlings subsequently affected. Plants that have 

 survived the early attack may give an inferior yield due to interrupted 

 growth, although the pods themselves may not become spotted. 



SYMPTOMATIC ASPECTS 



While the appearance of anthracnose on the various parts of the bean 

 plant has been described accurately by several investigators, a descrip- 

 tion is included here of its appearance as observed on different varieties 

 of beans under different conditions and at different stages of maturity. 



On the seed 

 The seed of the bean may be discolored by anthracnose, bright, rhizoc- 

 toniose, and brown rot, and by various mold-producing fungi. The 

 appearance most characteristic of anthracnose (Plate IV) is the decided 

 blackening of the affected parts. Usually the blackened area has a tawny 

 brown or tan-colored 2 border, or the entire diseased area may consist 

 of the latter color. Specimens are common in which the color of the spot 

 on the seed is lighter, varying from drab to snuff brown or saccardo umber. 

 The larger spots usually have a vinaceous buff to avellaneous-colon <l, 



■ The colors as (riven correspond to those (liven in Ridgway's Color Standards and Nomenclature, and, 

 while characteristic, there is considerable variation from them. 



