752 EXPERIMENT STATION EECOKD. [Vol.43 



Susceptibility of various plants to curly top of sugar beet, E. Carsner 

 (Phytopatholouy, {1919), No. 9, pp. Jil3-Ji21, fifjs. 7).— On account of the im- 

 portance of the curly top disease of sugar beets, a study was made to determine 

 how the virus or disease-causing factor overwinters. A large number of plants 

 were studietl, 14 species of plants, representing 8 families, being proved to be 

 susceptible, and 24 species of 17 families, nonsusceptible. From the standpoint 

 of overwintering it is thought that the red-stem filaree {Eroclmm ciciitarium) 

 is probably the most important. This plant is widely distributed in the West 

 and is specially abundant in the foothills of California. 



In connection with tliis investigation an attempt was made to determine liow 

 long virulent leaf hoppers retain their ability to ciMunuuiicate the disease after 

 they have been reniovetl from susceptible plants. In one instance a lot of leaf 

 hoppers kept on Atriplex polycarpa, a nonsusceptible species, retained their 

 virulence for 58 days, and on Rumex crispus (also nonsusceptible) for 111 days. 



The surface rot of sweet potatoes, L. L. Haeter and J. L. Weimer {Phyto- 

 pathology, 9 {1919), No. 10, pp. ^G5--'f70, pi. i).— During a study of di.seases ol 

 sweet potatoes, one to which the name surface rot is given has been under 

 observation. This is generally recognized as a storage trouble, and is charac- 

 terized by nearly circular brownish sunken spots, usually .several in number, 

 varying in size according to age, and attaining a maximum diameter of about 

 f in. Three well-marked stages are noted, the first, which consists in the for- 

 mation of siwts, the second, a shrinkage of the potato, and the third, the drying 

 up of the potato, making it useless for food. The latter stage is usually most 

 pronounced during the latter part of the storage period. 



Surface rot is said to have characteristics in common with black rot cau.sed 

 by Sphoeronema fimbriatum, but is sufficiently distinct to be readily distin- 

 guished. Isolations were made from sweet potatoes which showed the constant 

 presence of Fusarium oxysporum. Inoculation exi>eriments were repeated 

 several times with this organism, and a typical diseased condition obtained. 

 Infection is considered to take place at digging time or a little before it, or in 

 the early storage period. For control the authors recommend, wherever pos- 

 sible, the harvesting during dry weather and allowing the potatoes to dry in 

 the sun for a few hours. Conditions in the storage house should be dry and 

 warm when the potatoes are put in, so that curing will begin promptly. 



Heterosporium leaf spot of timothy, C. T. Gregory {Phytopathology, 9 

 {1919), No. 12, pp. 576-5S0, figs. 2). — A description is given of a leaf spot of 

 timothy due to Heterosporium phlei n. sp. The disease is said to have been 

 found throughout New York, and is thought to probably occur in all timothy 

 growing regions. 



A mode of treatment for chlorosis [in trees], G. Arnaud {Bui. Soc. Path. 

 Veg. France, 6 {1919), No. 6, pp. 117, 137-1.',6, figs. .2).— This method has been 

 noted from another source (E. S. R., 42, p. 647). 



Spraying and dusting [apples], C. F. Fetch {Ann. Rpt. Pomol. and Fruit 

 Groicing Soc. Quebec, 1918, pp. 27-29). — A condensed account is given of this 

 address, which dealt with the work and results of comparative tests with dust 

 (45 per cent talc, 45 per cent sulphur, and 10 per cent lead arsenate) and lime- 

 sulphur spray (1.01 to 1.006). Both of these treatments gave practically per- 

 fect fruit under conditions of close planting, regarded as greatly favoring the 

 spread of aijple scab. Combined or varied treatments were not encouraged on 

 account of cost and the satisfactory results obtained from the treatments indi* 

 cated above. 



Second year's success with dusting [apple trees], R. Cossette {Ann. 

 Rpt. Pomol. and Fruit Groicing Hoc. Quebec, 1918, pp. 1-7). — The progress of 

 the second year's experimentation with sulphur dust is considered to indicate 



