Bean Anthracnose 177 



the weather was favorable for infection to take place. The disease 

 did not spread because certain conditions favorable for it were not 

 allowed to exist. Some of the precautions to be taken are considered in 

 the following pages. 



Manner of planting 



Beans planted so close together that they form a dense mat of vines 

 favor the spread of the disease. The vines obstruct cultivation and do 

 not allow either the wind or the sunshine to dry out the moisture 

 beneath them. Spores of the pathogene, if present, are transferred from 

 one plant to others in contact, and are able under the moist conditions 

 to germinate and penetrate the tissues of the host without difficulty. 



The different varieties vary so much in their habit of growth and in 

 the size of their seed that it is impossible to give a general recommendation 

 for planting. Halsted (Halsted and Kelsey, 1895:28, and Halsted, 1897: 

 290) planted seed from 3 to 24 inches apart in rows 20 inches apart. 

 There was a considerable decline in the proportion of spotted pods and 

 also in the total yield of pods as the distance between the plants was in- 

 creased. Halsey concludes that 4^ inches is the most satisfactory distance 

 for Golden Wax beans. Ferris (1909:8) recommends, in addition to 

 selecting clean seed, planting the beans in bunches in the row far enough 

 apart so that the clusters do not touch one another. Edgerton (1909:5) 

 finds three beans to the hill, and the hills 18 inches apart, a very satis- 

 factory planting distance for beans grown in Louisiana. Fischer (1919) 

 says that Riehm suggests planting in hills 50 by 50 centimeters apart 

 instead of in drills, in order to permit good air drainage. Von Diakonoff 

 (1909) suggests planting the rows parallel to the direction of the prevailing 

 winds in order that the plants may be well aerated. 



Anthracnose will not spread through a field of beans planted in hills 

 as rapidly as it will through one planted in drills, because the vines in 

 one hill are somewhat isolated from vines in other hills for a considerable 

 part of the season, whereas in drills there is a continuous row of plants 

 in contact with one another, and anthracnose starting at any point in 

 the row would, under favorable conditions, spread the entire length. 

 To secure maximum protection by hill planting, the hills should be far 

 enough apart each way so that the vines of one hill will not come in con- 

 tact with vines of other hills; and this distance will vary with different 



