1»17] DISEASES OF PLANTS. 49 



describes a soft rot occurring at the base of the cornstalk, which Is thought to 

 be clue pi-obably to the admission of other bacteria. Since the disease is known 

 to be conveyed with the seed corn, llie importance of obtaining seed from non- 

 infested regions is pointed out. 



Dissemination of the angular leaf spot of cotton, R. C. Faulwetter {U. S. 

 Dept. Ayr., Jour. Ayr. Research, 8 (1911), No. 12, pp. ^57-475, pi. 1, fly. 1).— 

 The author presents data obtained during the summer of 1916 at the South 

 Carolina Experiment Station on the dissemination of the angular leaf spot of 

 cotton. He also suggests that the factors recognized as concerned in the dis- 

 semination of this disease may also have an important bearing on the spi'ead 

 of other diseases. 



Studies were made of insect carriers, seed-borne infection, winds, etc., in 

 relation to this disease, and the author concludes that much of its spread, 

 under the conditions of his experiments, was due to the carrying of bacteria 

 from Infected plants by wind-blown rain. This conclusion is largely drawn 

 from observations on the dissemination of the disease from inoculated plants 

 following two severe storms in July, in which high winds were accompanied 

 by heavy rains. The spread of the disease from the artificially inoculated 

 plants was determined to be in the direction of the prevailing winds during 

 these storm periods. Insects are considered as playing a very unimportant 

 role, while seed dissemination aside from its primary infection is not believed 

 to be important. 



Peanut wilt caused by Sclerotium rolfsii, J. A. McCi-intock (f7. S. Dept. 

 Ayr., Jour. Ayr. Research, 8 (1917),' No. 12, pp. i41-HS, pis. 2). — An account 

 is given of observations and investigations conducted at the Virginia Truck 

 Experiment Station to determine the cause and methods of control of the wilt 

 disease of peanuts first observed at the station in the summer of 1915. 



The disease appears under field conditions when the plants are from one to 

 two months old and continues to develop throughout the season. The fungus 

 attacks the shoots at or near the surface of the soil, killing the invaded tis- 

 sues. Wilted plants have been observed scattered over the entire area of each 

 plat, indicating that the causal organism is well distributed. Isolation and 

 inoculation experiments have shown the pathogenicity of the causal organism 

 and established its identity as S. rolfsii. 



In a test of six varieties of peanuts and one of the so-called hog goober 

 {Voandzeia siihterranea) marked differences were observed in susceptibility 

 to fungus attack. The variety Valencia appeared most susceptible, while Vir- 

 ginia Runner, Afrtcan, and Y. suhterranea were found practically imnmne to 

 S. rolfsii. Investigations have shown that the fungus retains its vitality in 

 the soil for at least three years, and as a consequence the planting of resistant 

 varieties is recommended rather than attempting to rid the soil of the pest 

 by rotation. 



In connection with the growing of peanuts, crimson clover is said to be com- 

 monly used as a winter cover crop. This plant did not suffer attack by S. 

 rolfsii so far as observations during the seasons of 1915 and 1916 showed. 



The Verticillium disease of the potato, G. H. Pethybridge {Sci. Proc. Roy. 

 Dublin Soc, n. ser.. 15 (1916), No. 7, pp. 63-92, pis. 2; abs. in Roy. Bot. Gard. 

 Kew. Bui. Misc. Inform., No. 4 (1916), pp. 110-112). — Reporting a more pro- 

 longed and more detailed study of the Verticillium disease than the one pre- 

 viou.sly noted (E. S. R., 34, p. 443), the author describes the general symptoms 

 as those of a process of gradual desiccation, resulting in the more or less 

 px'emature death of the plant. The mycelium of V. albo-atrum is found in 

 the wood vessels of all parts of affected plants, passing into the corresponding 

 vessels of growing tubers and thence into the young plants arising from such 



