DISEASES OP PLANTS. 249 



Preventive or remedial measures recuiuiueuded include giving access of air 

 and liglit by tliinniug and pruning both cacao and shade trees, collecting and 

 destroying the diseased fruits, and spraying stems and branches with Bordeaux 

 mixture. An extensive bibliography is appended. 



Lime-sulphiir wash for American gooseberry mildew (Sphaerotheca mors- 

 uvae), E. S. Salmon and C. W. B Wright (Jour. Hd. Agr. [Loyidon], 19 {191.3), 

 ^0. 12, pp. 994-1004). — As a result of experiments carried out during 1911 at 

 AVye, Kent, and during 1912 in North Kent, the authors state that different 

 varieties of gooseberries differ greatly as regards susceptibility to injury by 

 lime-sulphur wash. Some, as May Duke, will under ordinary conditions bear 

 repeated spraying throughout the season with tlie full strength (specific gravity 

 1.01) necessarj' to prevent attacks of American gooseberry mildew without 

 injury to the foliage. Some, as Crown Bob, will bear half this strength early 

 in the season, as in May and June, when spraying is most etficacious, but 

 prove more susceptible to injury later. Others, as Berry Karly. will bear half 

 strength early in the season in sliaded situations or cloudy weather. Still 

 others, as Valentine Seedling and Yellow Rough, can not safely be sprayed with 

 lime-sulphur wash. 



Recent observations on downy mildew, J. Chrestian {Rev. Colons Afrique 

 Nord, 1912, No. 1, pp. J,8-50, 1?>-1'6, 101-103, 11,0-143; ahs. in Mycol. CeiitbL, 2 

 {1913), No. 4, p. 223). — The author gives a resume of the principal results re- 

 cently obtained in a study of the development and biologj' of Plasmopara 

 viticola, which is held to attack grape leaves only by way of the stomata of 

 the lower surface. Experiments conducted during 190S to 1911 are held to 

 show that attacks of mildew always follow periods of high humidity and 

 nearly stationary temperature. Some suggestions are made as to the manner 

 of using copper fungicides to obtain the best practical results therefrom. 



A disease of lilac (Phytophthora syringee) new in Netherlands, T. A. C. 

 ScHOEVERS {Tijdschr. Plantcnziekien, 19 {1913), No. 2, pp. 4I-64, pis. 2).— A 

 description is given of a disease which has recently been shown to exist in parts 

 of Holland, killing buds and twigs of several varieties of lilac. The source and 

 relations of the fungus {P. syringw) thought to cause the trouble are still 

 under investigation. It is said that the usual fungicides afford but little pro- 

 tection, and that the principal measures that can be relied upon at present are 

 removal and destruction of the parts affectetl. 



Pine blister rust and currant felt rust, F. C. Stewart {West. N. Y. Hort. 

 Soc. Proc., 58 {1912), pp. 122-124).— The author gives a further discussion 

 (E. S. R., 21, p. 644) of this disease, which is now said to be established in New 

 York, Massachusetts, and Connecticut. 



The tecidial stage of the fungus {Cronartium riUcola) is stated to infect 

 only those pines which bear their leaves in clusters of five, speeiflcally Pinus 

 strobus, P. cenihra, P. lanibertiana, P. monticola, and possibly P. excelsa. prov- 

 ing very dangerous to the white pine, as it attacks both trunk and branches 

 and eventually kills the trees. While pines can not infect one another, they 

 can infect Ribes, nearly all wild and cultivated species of which are attacked 

 by the alternate stage (particularly the relatively unimportant black currant) 

 and are capable of spreading the infection rapidly from one to another for 

 considerable distances, also to pines at shorter distances. On Ribes the dis- 

 ease is conspicuous, but on Pinus it may not show for a year or more after in- 

 fection. Investigations are in progress to show whether or not this fungus can 

 winter on Ribes. 



It is thought that careful measures may control the disease to a great extent. 

 The recommendation is made that Ribes and susceptible pines be sufficiently 

 separated in cultivation; that no more black currants be planted, and that 



