1917] DISEASES OF PLANTS. 843 



Experiments carried on by the author and others indicate that the disease 

 may be kept in checl£ in southern peach orchards by proper pruning, cultiva- 

 tion, and especially fertilization. Of the fertilizers used, nitrate of soda proved 

 most efficient. 



In addition to the peach, B. pruni is said also to cause a disease of the plum, 

 affecting «specially the Japanese varieties. 



Black currant eelworm, Miss A. M. Taylob {Jour. Agr. Sci. [England], 8 

 (1911), No. 2, pp. 246-275, pi. 1, fig. i).— The author notes an attack of nema- 

 todes on black currant near Cambridge, England. The evidence indicates that 

 this parasite has been established here for some time, probably having been 

 more or less niaske<l by its association with the black currant mite, the symp- 

 toms of the two as described being similar in some respects. Although a study 

 which has been made of the nematode is given in some detail, its relationships 

 have not yet been determined. 



Sulphuring Concord grapes to prevent powdery mildew, F. E. Gladwin 

 and D. Reddick {Abs. in Phytopathology, 7 (1917), No. 1, p. 66). — The authors 

 report the dusting of Concord grapevines with sulphur-lime mixtures containing 

 25, 50, and 75 per cent sulphur flour, 95 per cent or more of which would pass 

 through a 200-mesh sieve. Comparisons were made with plants treated with 

 Bordeaux mixture and where powdery mildew (Uncimila necator) was 

 abundant, the vines receiving the du.st mixture showed much less mildew on 

 the gnipe clusters, although there was considerable burning with the larger 

 amounts of sulphur-lime. 



The generation of aldehydes by Fusarium cubense, E. C. Latheop {Phyto- 

 pathology, 7 {1917), No. 1, pp. i>}-i6).— Investigations having shown that alde- 

 hydes of various chemical constitution are deti'imental to plant growth, the 

 author experimented with F. cubense, the cause of the Panama banana disease, 

 and found that aldehydes were formed during the growth of the fungus on 

 synthetic culture media. The generation of aldehydes by F. cubense is be- 

 lieved to account, in a measure at least, for the pathological action of the 

 organism. 



Citrus canker investigations at the Florida Tropical Laboratory, R. A, 

 Jehle {Abs. in Phytopathology, 7 {1917), No. 1, pp. 58, 59). — A description is 

 given of some cultural characteristics of the canker organism, Pseudomonas 

 citri, as obtained in the laboratory. Positive results are reported to have been 

 secured from inoculations on grapefruit, ponderosa lemon, key lime, Citrus 

 trifoliata, sour orange, tangelo, sweet orange, tangerine, king orange, mandarin 

 lime, and kumquat. The disease also occurs on navel orange, mandarin, sat- 

 suma, common lemon, rough lemon, and ^gle glutinosa. 



Sour rot of lemon in California, C. O. Smith {Phytopathology, 7 {1917), No. 

 1, pp. S7-41, figs. 2). — A description is given of a sour rot of lemons and other 

 citrus fruits occurring during storage. The infected tissues soften, become 

 straw-colored, and collapse, changing into a more or less slimy, watery mass. 



A fungus has been isolated from diseased fruits which is considered identical 

 with Oospora citri-aura^itii, originally described by Ferraris (E. S. R., 14, p. 

 161). Artificial inoculations of the fungus on citrus fruits in moist chambers 

 gave positive results with lemons, oranges, grapefruit, and tangerines, the rot 

 showing within 48 hours. Green fruit of lemons, as well as twigs of Eureka 

 lemon, when inoculated, gave negative results. 



From the author's experiments, it is concluded that infection of lemons with 

 the sour rot fungus takes place only through some injury or from contact with 

 infected fruit. 



Two new camphor diseases in Texas, J. J. Tathjenhaus {Abs. in Phyto- 

 pathology, 7 {1917), No. 1, pp. 59, 60). — Authracnose of camphor, due to a species 



