54 Walter H. Burkholder 



A very characteristic and peculiar lesion occurs on the pods of Wells' 

 Red Kidney. About forty-eight hours after inoculation a ring spot 

 appears, somewhat less than a half inch in diameter and circling the point 

 of inoculation. The color of the ring is at first pale brown, and that of 

 the tissue within is a normal green. This ring spot does not retain its 

 identity long, since the central tissue soon collapses and turns brown. 

 These spots never show a water-soaked condition at any stage, and 

 usually at the end of a week they are dark olive-buff to tawny olive in 

 color. 



When bean plants are sprayed with a water suspension of the organism 

 and kept in a moist chamber for twenty-four hours, small spots are pro- 

 duced, but only on the young leaves. These lesions are very small, 3 

 millimeters in diameter, and under the conditions of observation have 

 never expanded. 



The Q strain, besides being a weaker pathogene than the New Jersey 

 strain, never produced the ring spot on the bean pods. Otherwise the 

 symptoms of the two strains are similar. 



Cross inoculations 



This pathogene, especially the New Jersey strain, has a very wide host 

 range among the leguminous plants. Of twelve species of legumes used 

 in inoculation experiments, eight proved to be susceptible. Experiments 

 were not conducted with any non-leguminous plants. All tests were made 

 in a greenhouse with a fairly constant temperature of approximately 80° F. 

 Inoculations were being made continuously on seedlings of Phaseolus 

 vulgaris, to make certain that a virulent culture of the bacterium was 

 being used. When the virulence lagged, reisolations were made. 



In all cases, seedlings or young plants of the species being tested were 

 employed. In most cases, inoculations were made also on pods of such 

 species. It was practically impossible, however, to obtain in the green- 

 houses pods of the scarlet runner bean or of the kudzu vine. The following 

 species proved susceptible to the disease: sieva bean (P. lunatus), white- 

 flowering hyacinth bean (Dolichos lablab), kudzu vine (Pueraria hirsuta), 

 cowpea (Vigna sinensis), yard-long bean (V. sesquipedalis) , soybean 

 (Glycine max) variety Wilson, and broad bean (Vicia faba). Good 

 infection was obtained on the pods of soybeans, but not on the seedlings. 



Negative results occurred when inoculations were made on scarlet 

 runner bean (P. coccineus), white-flowering lupine (Lupinus polyphyllus), 

 field pea (Pisum sativum var. arvense), and sweet clover (Melilotus alba). 



The foregoing results were obtained with the New Jersey strain of this 

 organism. The Q strain caused infection only on the common bean, the 

 kudzu vine, the cowpea, and the yard-long bean. This strain, not only 

 in its cultural reactions but also in its pathogenicity, appeared to be 

 weaker than the other. The type of lesion produced on the above-named 



