DISEASES OF PLANTS. 747 



currants are mentioned as i-esistant to the disease. For its prevention potas- 

 sium suli)hid is recommended, 1 kg. of the salt being used to 100 liters of water, 

 or if that proves too strong, 400 gm. to 100 liters of water may be used. 

 Spraying should be done every 8 to 10 days, beginning with the unfolding of 

 the leaves. Five to eight applications during the season are recommended. 



The use of different varieties of gooseberry in combating the American 

 g-ooseberry mildew, J. Eriksson {Dcut. Ohsthaii Ztf/., 1909, No. 22-23, pp. 

 3'iO-3.',U, Jigs. 2; abs. in Venlhl. Bait, [etc.], 2. Abt., 26 (.1910), No. .'f-5, p. 

 110). — The author states that there are two ways of combating the ravages of 

 the American gooseberry mildew, one by vigorous pruning away of diseased 

 canes in the late fall and winter, which is usually a very unsatisfactory 

 method, and the other by judicious selection of the more resistant varieties of 

 currants and gooseberries to breed a variety that will be immune to the disease. 



The pathog'enic spotting of the annual canes of the grape, E. Molz (Centbl. 

 linkt. [ct(%], 2. Abt., 20 (1908), No. 10, pp. 261-272, pis. 2, fifis. 13; abs. in Bot. 

 Centbl., Ill (1909), No. 25, pp. 67,7, fi-'/S).— The spots found on the young wood 

 of grapevines are figured and described imder the following heads: Cortical 

 warts (young lenticcls), so-called pearl glands, Oi'dium sjiots (Vncinula neca- 

 tor), anthracnose (Sphaceloma anipclininn), sjutls due to Bordeaux spray, and 

 those caused by hail or other mechanical injuries. 



A disease of the pedicels of the grape, P. Pacottet (Rev. Vit., 32 (1909), 

 No. SI'i, pp. 98, 99). — The author claims that this disease is often very destruc- 

 tive to the crop, as it attacks the pedicels at the time the berries are ripening. 

 It is usually precwled by a pericxl of bad weather or extreme changes in tem- 

 I)erature, especially .-ifter a sudden cold spell. The disease first manifests itself 

 on the pedicels as a brown ring or spot more or less extended. The pedicels 

 attacked dry up without the berries apparently sutS'ering, but after a little they 

 fade without ripening and either dry up or rot according to the degree of 

 humidity. In the last stages of the disease, a fungus (Botrytis cinerea) infects 

 the necrotic tissues. 



Authorities are divided as to its causes. Some claim it is a fungus (B. 

 einerca), others a bacterial aliCection, and still others maintain that it is physio- 

 logical, due to a disturbance of the nutrition by sudden chilling succeeding a 

 ])eri()d of great heat and, active movements of the sap. 



The remedies suggested are the development of an excellent root system by 

 uniform cultivation, the avoidance of vigorous pruning, and the use of light 

 fires to protect the stems from sudden changes of temperature. 



Tire blight of pears, apples, quinces, etc., H. H. Whetzel and V. B. Stew- 

 art (Neio York Cornell Sta. Bui. 272, pp. 31-51, figs. 19). — The purpose of this 

 bulletin is to present the history, symptoms, and causes of this disease, together 

 with the results and conclusions as to its dissemination and control which may 

 be of immediate and direct value to the orchardist. 



Thorough and rigorous pruning of all cankers and diseased spurs, together 

 with the proper disinfection of all wounds, is the method recommended for con- 

 trolling this blight. 



Some apple diseases, C. Brooks (New Hampshire Sta. Bui. l.'/'i, pp. 109-138. 

 figs. 29). — Popular descriptions, together with suggestions for treatment, are 

 given of apple scab (Ventiiria pomi), fruit spot (CyHndrosporium pomi), fruit 

 pit, sooty blotch and fly speck (Leptothi/rium pomi), apple rust (Gymnosporan- 

 (liuin globosum), black rot or canker (Uphwropsis maloruni), bitter rot (Glome- 

 relUi rufomaculans), fire blight (Bacillus amylovorus), crown gall (Pseudo- 

 inonas tuniefaciens), European apple canker (Neetria ditissima), blister canker 

 (Nuinniuhtria discreta), and waiter injury. 



