DISEASES OF PLANTS. 551 



conditions will be determined by the number of spores which exist in the 

 neighborhood of the vines. 



As to the various sprays tested, the author lists the following in order of 

 efficiency: (1) Bordeaux and Burgundy mixtures (3 to 4 parts to 100 of copper 

 sulphate); (2) Burgundy (2:100), Bordeaux (2:100), Burgundy (2:100 with 

 colophony), Bordeaux mixture plus molasses, Burgundy (2:100 plus soap), 

 and copper acetate (1: 100 and 2: 100) ; (3) Burgundy and Bordeaux mixtures 

 (2: 100, applied 4 and 8 days after mixing) ; (4) Bordeaux and Burgundy mix- 

 tures (1:100) ; (5) oxychlorid of copper (500 gm. per hectoliter) ; (6) oxychlorid 

 of copper (300 gm. per hectoliter), ammoniate of copper (1:100 and 2:100) ; 

 (7) chlorid of copper (240 gm. per hectoliter) ; and (8) aceto-arsenite of copper 

 (200 gm. per hectoliter), and sulphate of copper (150 to 300 gm. per hectoliter). 



Spraying' for black rot of the grape in a dry season, D. Reddick, C. S. 

 Wilson and C. T. Gregory (Xcic York Cornell Sta. Bui. 296, pp. 573^588, 

 figs. ^). — The results are given of experiments conducted during 1909 and 1910 

 on spraying with ammoniacal copper carbonate, Bordeaux, and lime-sulphur 

 mixtures for the control of the black rot of the grape, in continuation of pre- 

 vious work (E. S. R., 21, p. 344). 



The experimental plats were located in a vineyard from which no grapes had 

 been picked for many years because of the ravages of the black rot and downy 

 mildew. The sprays used during 1909 were 4 : 4 : .50 Bordeaux mixture (4 and 5 

 applications), 3 : 3 : .50 Bordeaux mixture (5 applications) , 10 : 6 : 50 ammoniacal 

 copper carbonate (5 applications), 1:25, 1:30, and 1:40 commercial lime- 

 sulphur mixture (5 applications), and 8:8:50 self-boiled lime-sulphur mixture 

 (5 applications). Some tests were also made with bagging the fruit as a means 

 of controlling the disease. 



In 1910 the sprays used were 4 : 4 : 50 Bordeaux mixture (2, 3, and 4 applica- 

 tions), 1:50 and 1:65 commercial lime-sulphur mixture (4 applications), 

 8 : 8 : 50 self-boiled lime-sulphur mixture (4 applications), and 5 : 3 : 50 ammoni- 

 acal copper carbonate (4 applications). 



The results from these experiments for the 2 seasons showed that with the 

 best fungicide used for controlliug the black rot the applications necessary 

 to control the disease were applied with actual loss when compared to the 

 yields during these 2 years from the unsprayed vines. All of the sprays used 

 were ineffective against the rot except the 4 : 4 : 50 Bordeaux mixture, which 

 maintained its preeminence as a spray for black rot. The time of application of 

 the sprays proved to be the most important single factor in the control of this 

 disease. 



The author recommends clean culture of the vineyard grounds, the destruc- 

 tion of all mummies left on the vines, keeping the vines clear of basal trailing 

 sprouts, and spraying with a 4 : 4 : 50 Bordeaux mixture, the first application of 

 the mixture being made when the third leaf is showing, the second just after 

 the fall of the blossoms, and two other applications at intervals of 10 to 14 days, 

 according to the weather conditions. Each application should precede rather 

 than follow a rain, as it was found that an infection followed only a rain of 

 some duration. 



The conditions of resistance of the vines to mildew, J. Laurent ( Bm?. Mens. 

 Off. Rcnseicj. Agr. [Paris^, 10 {Wll), No. J,, pp. J,64-471).—The substance of 

 this article has previously been noted from other sources (E. S. R., 25, p. 45). 



Scaly bark or nail-head rust of citrus, H. S. Fawcett (Florida Sta. Bui. 

 106, pp. 1-il, figs. 22).— This bulletin comprises the results of several years' 

 study of this disease, in which the cause of scaly bark, means of control, symp- 

 toms, distribution, history, and development were investigated; inoculation 

 experiments and experiments for the control of the disease are also given. The 



