238 



SCIENCE 



[N. S. Vol. L. No. 1288 



connection with, a general consideration of 

 tliis problem and certain specific details. 



It was the sense of the committee that geo- 

 chemical investigation should have appro- 

 priate representation in the American Section 

 of the proposed International Geophysical 

 Union. 



It was recommended to postpone the ques- 

 tion of the formation of an American Geo- 

 physical Society until after the Brussels 

 meeting. 



Harry O. Wood, 

 Acting Secretary 

 (To he concluded) 



SPECIAL ARTICLES 



BACTERIUM SOLANACEARUM IN BEANS 



In June, 1919, some badly diseased bush 

 beans were received from Lynn Haven, 

 Florida. The leaves were wilted and more or 

 less brown. Often the petioles also were 

 brown and wilted to their base. The roots 

 were brown and the epidermis somewhat de- 

 cayed in places. The woody parts of the 

 plants, both stems and roots, had dark stained 

 vascular bundles. Cross sections examined 

 microscopically showed from 50 to 100 per 

 cent, of the vessels to be full of bacteria and 

 no fungi were visible. As the discoloration of 

 " the leaves was generally uniform, with no 

 lesions apparent while the roots showed lesions 

 and contained bacteria in great numbers the 

 supposition was that the disease must be due 

 to the bacteria and that they must have 

 entered through the root system. The loss in 

 the Florida field was about 20 per cent, of the 

 beans planted. 



Agar-poured plates gave pure cultures of a 

 white baeterifil organism having all the char- 

 acteristics of Bacterium solanacearum. 



Cultural work in other media and needle- 

 prick inoculations made with sub-cultures of 

 colonies taken from the poured plates con- 

 firmed this diagnosis. 



A number of diilerent legumes were in- 

 oculated by pricking the bacteria into the 

 stems. Of beans, Waxbush, Eed Valentine 

 and Eefugee proved very susceptible. These 

 plants began to wilt two days after inocula- 



tion and a number were entirely wilted and 

 fallen over in seven days. In addition to 

 those already mentioned, good infections were 

 secured in: Lima beans (Fordhood variety), 

 Pinto beans (a brown speckled variety) and 

 Great Northern (a white Navy bean). 



Inoculated in peas this parasite acts more 

 slowly than in beans, but is not without patho- 

 genic properties at least on some varieties. 

 Following stem inoculation by needle pricks 

 there is a slow drying and shriveling of the 

 leaves but not a sudden wilt. The plants be- 

 come stunted. Cross sections of the stems 

 show bundles discolored and containing bac- 

 teria though in less abundance than in in- 

 fected beans, tobaccoes, or tomatoes. Tele- 

 phone, Little Marvel and Mammoth Luscious 

 Sugar were the varieties of peas that became 

 infected. The organism has been reisolated 

 from both beans and x>eas, and proved to have 

 the same characters and infectiousness (tested 

 on tobacco and beans), as the original culture. 



The organism was also found to be in- 

 fectious to soy beans (variety Ito San) and to 

 cowpeas (variety Black Cow). 



Tobacco and tomato plants used for con- 

 trol showed typical Bacterium solanacearum 

 infections. 



So far as known this is the first time this 

 disease has been observed in beans, peas, soy 

 beans or cowi)eas, although known to occur in 

 peanuts, in Mucuna sp., and in some other 

 legumes. Fortimately beans appear to be very 

 susceptible only in early stages of growth. 

 Erwin F. Smith, 

 Lucia McCulloch 



SCIENCE 



A Weekly Journal devoted to the Advancement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SCIENCE PRESS 



LANCASTER. PA. GARRIS^J, N. Y. 



NEW YORK, N. Y. 



Entered in the post-«ffice mt Lancmfttr. Pa., u tecond clan nutlv 



