DISEASES OF PLANTS. 153 



ties Ben Davis and Black Twig seem more subject to this trouble than others, 

 York Imperial suffering less severely and Winesap being hardly affected at all. 



During the seasons of 1910 and 1911 spraying experiments for the control of 

 these leaf diseases were carried on in a number of places in Virginia to test the 

 value of different fungicides, the times of application, etc. The experiments 

 showed that dilute lime-sulphur solution is as effective in controlling the leaf 

 spot and scab as standard Bordeaux mixture. Where the scab is not abundant 

 the first spraying should be made immediately after the falling of the flowers, 

 followed by a second and third application at intervals of from 15 to 20 days. 

 Where scab is abundant an additional application of the spraying material 

 should be made just before the blossoms open. Bordeaux mixture appeared to 

 be the only fungicide which was successfully used for combating bitter rot. 

 For this purpose 3 applications should be given the trees, the first between June 

 20 and July 1, with subsequent sprayings at intervals of from 15 to 20 days. 

 The addition of iron sulphate to lime-sulphur or Bordeaux mixture was found 

 to increase the sticking properties of the fimgicides without affecting their 

 value in any sense. It was also found that arsenate of lead aside from being 

 a good insecticide had some value as a fungicide. 



The injury to the foliage attributed to spraying mixtures is sometimes caused 

 by the use of too great quantity or improperly made mixtures. It was found 

 that fruit may be burned with lime-sulphur if sprayed in very hot weather. 

 Tender skinned apples were affected by Bordeaux mixture in a similar way if 

 sprayed early in the season. The danger of russeting is very slight 2 months 

 after blooming and later. Where early applications of the fungicides are neces- 

 sary the authors recommend the use of lime-sulphur for the first 2 sprayings. 



Experiments on the simultaneous treatment for the control of downy 

 and powdery mildew, G. Marteixi (Separate from Agr. Etneo, 1911, No. 4. 

 pp. 7). — The results of experiments for the combined treatment of grapes to 

 control the downy and powdery mildew are given. The vines were sprayed 

 with Bordeaux mixture to which was added an alkaline polysulphid, Bordeaux 

 mixture followed by applications of sulphur, and a proprietary mixture of 

 copper and sulphur. Three applications were given to different lots of over 

 6,000 grapevines in the experiment, and the cheapest and most efficient fungi- 

 cide was the Bordeaux mixture combined with the alkaline polysulphid. 



Invasion of Europe by the American gooseberry mildew and oak mildew, 

 G. KocK (Zfschr. Pflanzcnkrank., 20 (1910), No. 8, pp. .'f52-m!,55 ; abs. in Centbl. 

 Bakt. [ctc.'\, 2. Ait., 31 (1911), No. 11-15, p. S-'/o). — This continues communica- 

 tions by the author on this subject (E. S. E., 22, p. 743; 23, p. 50: 24. p. 747), 

 giving here dates and places of first appearance or early appearances of each of 

 these mildews in this region. 



The influence of Hemileia vastatrix on the culture of coffee in Java, 

 P. S. J. Cramer (Rev. Agr. NouveUe-CaUdonie, 1911, Nos. 12, pp. 2J,-50; 13, 

 pp. 16-24). — An account is given of H. vastatrix in Java, the influence it has 

 had on the Arabian coffee production, and means that have been undertaken 

 for its control. 



The production of coffee under government control in Java has fallen from 

 an average of 923,.333 piculs (123,111,100 lbs.) in the 5 years from 1880 to 1885 

 to 81,746 piculs in the 2 years from 1906 to 1908. due, it is claimed, to the dis- 

 astrous invasion of the fungus. To combat the disease, spraying and the grow- 

 ing of resistant varieties have been resorted to. Coffea liberica, C. robusta, and 

 other species, and some of their hybrids appear quite resistant, and their intro- 

 duction has been successfully accomplished. Spraying with Bordeaux mixture 



