DISEASES OF PLANTS. 651 



tary materials advertised as of value for the control of fire-blight of pears and 

 apples. 



One mixture, called Blight Specific, for which great claims have been made, was 

 tested, and it was found that it not only failed to control the disease, but also 

 that as a result of its use the trees seemed to suffer positive injury through 

 the blackening of the wood. A chemical analysis of the substance showed that 

 it consisted of over 92 per cent sulpliur together with some powdered chai-coal 

 and asafetida. So far as New York conditions are concerned, the author 

 thinks that it is worthless for the control of the pear blight and is actually 

 injurious to the bark and wood of the trees, making serious wounds into which 

 rot fungi gain entrance. 



The apoplexy of the grape in Anjou, E. Vinet (Rev. Vit., 32 (190D), No. 835, 

 pp. 676-6S1, flo>i. 3). — This disease is quite prevalent in Anjou and is gradually 

 destroying many vineyards. The claim is made tliat the dead stems show 

 necrosis of the tissues but that the disease is not found in the roots. Old stems 

 that are dying from this cause are often found infected with two species of the 

 higher fungi. Poly poms versicolor and Stereum hirsutum, the mycelia of which 

 were found ramifying throughout the necrotic tissues, and the question is 

 raised as to whether they are not a secondary cause of the death of the vines. 



The vine growers of that region have found the following remedies of mucli 

 value in combating the disease: Destruction of badly diseased, old, and dying 

 plants, rigorous pruning away of the affected portions on the younger living 

 vines, sterilization of all wounds by painting them over with coal tar or other 

 antiseptic, and the treatment of the cut surfaces of the cuttings with a solution 

 of 30 to 35 per cent of sulphate of iron. 



The black rot of grapes, D. Keddick (West. N. Y. Hart. Soc. Proc., 54 {1909), 

 pp. 127-13.'f, figs. 3). — A description is given of the black rot of grapes, with 

 suggestions for its control. 



The physical and chemical composition of grapes when diseased by Oidium, 

 R. AvERNA (Hoi. Arbor. Ital., 5 ( 190!)), No. 2, pp. 87-90). — Several varieties were 

 analyzed. It was found that the disease materially reduced the average weight 

 of the bunches and the seeds, decreased the amount of sugar, tannin, and tar- 

 taric acid produced, made the yield of the must less and almost completely de- 

 stroyed the coloring m;itter, but increased the amount of lees and the acidity 

 of the product. 



[Cooperative spraying experiments], L. R. Taft (Mieliigaii Sta. Rpt. 1909, 

 pp. 152-157). — An account is given of some cooperative spraying experiments 

 for the prevention of black rot. the experiments having been begun as a result 

 of observations made on the disease in 11)05. The first year's experiments were 

 not very accurately conducted and the results were not deemed conclusive, but 

 in 1907 and 1008 the spraying was mucli more carefully done and the results 

 fully justified the efforts made for controlling the disease. 



For spraying vineyards it is believed advisable to use a 4 : 4 : 50 Bordeaux 

 mixture for the earlier sprayings, the amount to be reduced to 3 : 3 : 50, or if 

 spraying is required after July 15 to 2 lbs. of copper sulphate to 1 lb. of lime 

 in 50 gal. of water. The amount I'equired for spi'aying an acre of grapes will 

 vary, but in general about 50 gal. per acre will be required during the early, 

 part of the season and from 60 to SO in subsequent applications. The estimated 

 cost of spraying an acre with 5 applications of Bordeaux mixture as recom- 

 mended above is $4.90. 



In addition to spraying with Bordeaux mixture, some observations have been 

 made on dust sprays and on lime-sulphur solutions, but nothing was found as 

 valuable as Bordeaux mixture prepared in the way recomoiended above, 



