DISEASES OF PLANTS. 157 



Notes on Pseudomonas campestris, II. A. Harding and M. J. Pbucha [Abs. 

 in Science, n. ser., .'/ (1905), No. 535, pp. 483, f&4)- — An accounl of experiments 

 carried on at the New York State Station with the black rol organism which attacks 

 cabbage, cauliflower, and allied plant-. 



Previous investigations regarding this parasite have been reported E. S. h., 16, 

 pp. 170, 480), and in the presenl paper an accounl is given of the resistance of 

 the organism to drying. When exposed on sterile cover slips the bacteria did nol 

 jurvive a 10-day drying, hut they wen- found to retain their vitality on cabbagi 

 lor more than a year. Cabbage plant- inoculated with pure cultures obtained from 

 Beed 13 months after infection showed a blackening of the veinlets in the leaf, and 

 other evidences of disease after an interval of 16 days. 



Peach leaf-curl (Bd. Agr. and Fisheries [London], Leaflet 120, pp. 3, fig. /). — A 

 description is given of the peach leaf-curl, caused by Exoascus deformans, together 

 with suggestions for its control. It is stated thai the remedies recommended in the 

 United States are inadequate in England, repeated experiments having shown thai 

 ipraying with Bordeaux mixture will no1 wholly control the disease. In addition 

 to spraying, the removal of the diseased shoots which hear the characteristic tufted 

 leaves is recommended. 



Bacterial infection by way of the stomata in black spot of the plum, 

 I'.. F. Smith (Abs. in Science, n. ser., 21 (1905), No. 535, p. 502). — In continuation of 

 previous investigations (E. S. R., 14, p. •">: , .l I the author has studied the bacterial 

 infection of the black spot of the plum. 



Numerous infections wen- obtained through the stomata by spraying dissolved 

 cultures of the Pseudomonas pruni over leaves and green fruits. When this was done 

 during damp weather the spots became visible in 7 days. Microscopic investigations 

 showed the characteristic appearance of the disease and the organism was readily 

 recovered by means of agar plates. A neighboring tree inoculated at the same time 

 ami in the same way, bul with a different organism, never showed any results. No 

 fapots were obtained on full-grown plums, although numerous attempts were made 



under what appeared to he favorable conditions. The disease appears to he one 

 limited strictly to meristomatic tissues 



The cedar and pear rust, I'. Pass? | Rev. Hort. [Paris'], 11 (1905), No. 5, /</>. 

 / 14-118, figs. 8).- -The author describes the relation between the Gymnosporangium 

 Occurring on cedars, or species of Juniperus, and the Rcestelia stage occurring on 

 pears, etc. 



Diseases of the grape in Ontario in 1904, \V. T. Macoun ( ( '<m<i<l<i Expt. Farms 

 Rpto. 1904, pp. 124-125) . — The author briefly describes the anthracnose, black rot. 

 brown rot or downy mildew, powdery mildew, ripe rot, and leaf blighl of grapes. 



A fungicide for use in combating- grape gummosis, m: Sokolnicki i Prog, 

 tar. et Vit. I /•-''/. VEst), 26 (1905), No. l .'. />. 355). A formula isgivenof a fungicide 

 which is recommended as a wash for grapevines to protect them against gummosis. 

 The fungicide consists of water UK) liters, mercuric nitrate 300 gm., and sulphuric 

 acid siithcient to make the solution clear. 



A coffee leaf fungus, II. N. Ridley (Agr. />'"/. Straits "ml /■)</. Malay St<it,s, 

 •-' i 1904), No. / .', pp. /'.''-'. 493). — A disease is described which attacks the leaves and 

 berries of coffee, forming over the leaves a dense white mycelium and causing the 

 unripe berries to become depressed over the surface ami more or less blotched with 

 ■own. 



The author suspects the fungus to he a species of ( 'ort iciiun, hut so far has not 



■Ben able to positively identify it. The disease is most troublesome during wet 

 weather or in thickly shaded portions of the plantation, and it largely disappears 

 with the advent of dry weather. As a precautionary measure it i- recommended 

 that where the fungus occurs steps Bhould he taken to secure a better circulation of 



air and a freedom from to,, much moisture. 



