DISEASES OF PLANTS. 271 



rily 2 applications should be given the trees, the first about April 15 and the second 

 about May 20. One hundred liters of this solution should not cost more than about 

 50 cts. and this would be enough to treat from 10 to 20 trees, depending upon their 

 development. 



Notes are given on a lumiber of olive insects, with suggestions for their eradic-ation 

 and formulas for fertilizers which are recommended for use in connection with oUve 

 culture. 



Cacao canker and its eradication ( Trop. Ar/r., 23 {1903), No. 1, p. 31). — xVtten- 

 tion is called t(j the cacao canker in Ceylon and recommendations made for its eradi- 

 cation. The canker is said to have increased, and for its further eradication the 

 author suggests that some legislation should be provided to protect private property 

 from injury through tlie neglect of those who do not attempt to combat the disease. 

 The disease may be prevented to a considerable extent l)y i)runing and thinning out 

 the sliade so as to secure a l)etter circulation of air through the trees, and l)y cutting 

 out and burning all the dead trees and 1)ranches together with all the diseased areas 

 shown on otherwise healthy trees. By concerted action of this kind it is believed 

 that the disease can be almost entirely eradicated. 



Black rot and its treatment, A. Prunet {Rev. Vit., 19 {1903), No. 494, pp. 641- 

 645; 20 {1903), No. 498, j^p. 14-19) . — A resume is given of the author's investigations 

 on the development and treatment of the black rot, the number, duration, and inter- 

 val of the different invasions of the fungus being shown and the period of incubation 

 l>eing described. For the prevention of the disease the author recommends thorough 

 spraying with P>ordeaux mixture. 



Treatment of black rot of grapes, A. Pruxet {Rev. Vit., 20 {1903), No. 499, pp. 

 39-42). — According to the author, fungicides containing an equal amount of copper 

 in solution have equal efficiency without reference to their acid or neutral reaction. 

 When the cost of application is to be considered Bordeaux mixture, composed of 2 kg. 

 of copper sulphate to 1 kg. of lime in a hectoliter of water is recommended. In 

 spraying, all portions of the vines and leaves should be well covered with the fungi- 

 cide and repeated applications should be made as conditions require. 



This application, while it has some effect on the powdery mildew, does not entirely 

 {irevent it, and it is recommended that a sj^ecial application of sulphur should be 

 given during July as supplemental to the other treatments. 



Black rot and grape mildew, J. Capus {Rer. Vit., 20 {1903), No. 500, pp. 70- 

 74). — An account is given of observations on the occurrence and treatment of l)]ack 

 rot and downy mildew of grapes during 1902. The dates are given upon which the 

 <lifferent diseases appeared, there having been 5 distinct attacks of each fungus. The 

 period elapsing between the successive appearances of the 2 fungi was approximately 

 the same, the exact period varying according to the atmospheric or other conditions. 

 Suggestions are given for comljating these diseases, spraying with Bordeaux mixture 

 ]>eing recommended for both the black rot and the Plasmopara. 



Notes on grape mildew, L. Ravaz {Prog. Agr. et Vit. {Ed. rEst),2'f {1903), Nos. 

 21, pp. 629, 630; 22, pp. 658-660, pis. '3). — Notes are given on tlic appearance of the 

 <^owny mildew {Plaxmopara riticoJa) and its effect upon the grapevine. The first 

 attack of mildew is said to be rather insignificant, followed by more destructive 

 attacks. The subsequent occurrence of the fungus may be controlled to a large 

 extent by the thorough application of copper fimgicides. 



Grape mildew, J. Dufour {Chron. Agr. Canton Vaud, 16 {1903), Nos. 9, pp. 234- 

 247; 10, pp. 274-28(^ . — A description is given of the mildew of grape due to Plosmo- 

 jKtra viticola, and an account of the very destructive outbreak of this disease during 

 11)02. Brief reports are given from a large number of grape growers on the occur- 

 rence and characteristics of the disease and upon the various means ado{)ted t(j i)re- 

 vent the spread of the fungus. The different fungicides used are described and their 

 formulas and directions for ap])li<-ati(iii given. 



i; 



