i6i 



appear. It is well to burn the refuse in the field, avoid successive 

 plantings of beans, and select plump healthy seed. Experiments 

 with varying results have been conducted with a view of determin- 

 ing the influence of hot w'ater and certain chemicals on the seed 

 before planting. 



Bacto'iosis, bliglit, or zc/'/f {Pseudomonas phaseoli, Sm.). — Al- 

 though this disease is not as common as anthracnose it is more 

 destructive when it once breaks out. Whole plantations have been 

 wiped out within a few days. It is caused by a species of bacteria 

 which produces large brown patches on the leaves, stems, and pods, 

 at first watery but later becoming dry and hard. It is believed 

 that insects going from one plant to another may be a means of 

 infection. The treatment for this disease is the same as for anthrac- 

 nose. 



Bean Rust {Uroniyccs appcndiculaia, Lev.). — This disease is 

 caused by a fungus, but as the injury is chiefly confined to the 

 leaves, it is not so serious as those previously described. It appears 

 in the form of small rusty specks which, unlike the anthracnose, 

 are somewhat elevated. The spots later become dark brown, which 

 is the color of the winter spores. Early spraying with Bordeaux 

 mixture will prevent damage. 



The Dozi'iiy Mildczv of Lima Beans (Phytophthora phaseoli, 

 Thaxter). — This is a very serious disease, but fortunately is re- 

 stricted to the Lima beans. A downy appearance of the young 

 pods is the first indication of the presence of the disease. The 

 downy area increases and the whole bean becomes coated and 

 finally rots. The disease is believed to be transmitted by insects, 

 especially bees. In regard to the treatment of the disease Dr. 

 Sturgis^ says : " The conclusions drawn from the experiments with 

 fungicides show that even in a season most favorable for the Lima 

 bean mildew, a thorough treatment of the vines with Bordeaux 

 mixture wdll insure a crop. The selection of well-drained land and 

 a light soil, reducing the number of vines in a hill and planting the 

 poles erect, will insure conditions as little favorable to the develop- 

 ment of the fungus as possible." 



Other diseases. The Bean Leaf Spot ( Isarisopsis griseola, Sacc.) 

 and the Bean Leaf Blotch (Cercospora crnenta, Sacc.) are two fun- 

 gous diseases which occasionally injure the foliage, which can be 

 controlled by spraying with Bordeaux mixture. 



' Rpt. Conn. Exp. Sta., 1897, pp. 164, 165. 

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