to show some benefit from tlie spraying:, but the plantings were not 

 large enough to give eoneliisive evidence. It is doubtful whether 

 spraying will prove effective enough to pay for the additional expense. 

 It must be noted with regard to varietal resistance that seed infection, 

 a most important point, was not considered. 



Later in the season a second crop of beans was grown on a neigh- 

 boring plot of ground. The varieties were refugee. 1000-1 (both 

 northern types), a black Venezuelan bean, and the native red bean. 

 Only the slightest trace of anthracuose appeared, and this on the 

 ''refugee." Whether this freedom from disease was attributable to 

 weather conditions, to clean seed or to varietal resistance was not 

 apparent. Further tests are necessary. 



Downy Mildew. — A virulent disease, caused by a fungus of the 

 Phycomycetes or alga-like fungi, attacked the refugee and lOOO-l 

 beans of the second planting. The Venezuelan black wax and native 

 red types in adjacent parallel rows were unaffected. The trouble 

 appeared over night practically, and within a week had destroyed 

 large portions of the plantings. 



A plant once attacked rapidly succumbed, the leaves wilting and 

 drooping in such a way as to suggest root troubles, but examination 

 of early stages revealed healthy stems and roots, the tops being 

 attacked first. The withering and eonsecpient death of an infected 

 plant, however, occurred very speedily. At times single plants only 

 were attacked, but more commonly entire sections of a row up to 

 eight or ten feet in length were killed, the disease spreading rapidly 

 from the original point of infection. The most striking feature of 

 this disease was the fungus growth on the pods occurring as floccu- 

 lent (fluffy) white masses of mycelium obscuring tlie upper half of, 

 or even at times the entire length of. the pod. Attacked pods were 

 destroyed by soft rot. 



The damage that this disease would be capable of, if bean grow- 

 ing were attempted on a couuuercial scale, was well illustrated by tlie 

 fate of a peck of the refugee variety which was left for several days 

 in the picking basket. When examined the entire lot had been matted 

 together by the mycelial masses of the fungus and completely soft- 

 rotted. Shipping this variety at least would have been a decided 

 failure. 



Time has not permitted any further studies of this disease. Hence 

 the systematic position of the fungus involved has not been deter- 

 mined. Tt is not J^hytoplwra phoseoli Thaxter, which fungus, how- 

 ever, has been reported (5)^ on lima beans in Porto Rico. 



' Reference is made by number to "Literature c-itetl," p. 11' 



96 



