DISEASES OF PLANTS. 149 



Gall formations on apple trees, Julie Jaeger {ZtscJir. Pflanzcnkraiik., 18 

 (1908), Xo. 5, pp. 251-212, pJ. I, fiij. I). — Anatouiical studies are rei)ortecl on 

 galls observed on several varieties of apples, and the causes of similar galls on 

 a number of other plants are pointed out. Among these ai"e mentioned the 

 crown gall, various cankers due to fungi, and galls caused by different insects. 

 The galls occurring on the apples are attributed for the most part to attacks of 

 mites. 



Fall blossoniiug of the apple induced by the black rot, H. S. Keed {I'lant 

 Wuriil, 11 ^{1908), A'o. 11, pp. 250, 257). — A description is given of the fall 

 blooming of an apple tree at the Virginia Station, which was induced by a 

 serious infection of the black rot {Sphwropsis maloruin). The Sph?eropsis 

 cankers were abundant and had caused the death of over half of the top of the 

 tree. Many of the small branches made little growth during the season, and it 

 was upon these that the fruit buds opened. 



Lime-sulphur mixtures for the summer spraying of orchards, W. M. Scott 

 {U. S. Dcpt. A[/r., Bin: Plant Indus. Circ. 27, pp. 17, pgs. 2). — The success 

 attained in exiierinients in 1907 (E. S. R., 19, p. 1154) with self-boiled and 

 unboiled lime-sulphur mixtures for the control of apple and peach diseases led 

 to the repetition of the experiments on a larger scale in 190S, and the principal 

 features of these experiments are discussed. Home-boiled, factory-boiled, and 

 self-boiled lime-sulphur mixtures were employed and their efficiency in prevent- 

 ing diseases of peaches, cherries, and apples was tested, together with their 

 effect upon the host plants. 



The lime-sulphur mixtures were found to be very efficient in tlie control of 

 the diseases of the fruit trees mentioned and less injurious to the foliage than 

 Bordeaux mixture. In the experiments with the self-boiled lime-sulphur mix- 

 ture, it was found that for peach foliage considerable injury was done to the 

 leaves where the mixture was allowed to stand too long with a minimum amount 

 of water. Where cold water was used to stop the cooking, no injury resulted 

 from its use. The experiments with this fungicide showed that it was quite 

 efficient in controlling peach scab, brown rot, cherry-leaf spot, and apple scab. 



Where the self-boiled mixture is employed as a fungicide, the last treatment 

 should be made at least a month before picking time, otherwise the fruit will 

 be badly stained. 



The commercial lime-sulphur solutions, two brands of which were used, 

 adhered better and remained effective longer than the self-boiled mixture. 



The use of arsenicals with the commercial lime-sulphur is as yet an unset- 

 tled question. With the self-boiled mixture arsenate of lead or Paris green 

 may be usetl, but since Paris green is injurious to the peach, it is unsafe to use 

 it in spraying peach trees during the growing period. 



Concerning- the influence of sulphur dioxid fumes on fruit and fruit rot 

 fungi, T. ZscHOKKE (Landw. Juhrh. Scliwciz, 22 (1908), No. L'l, pp. 899-908, 

 figs. 8). — The effect of sulphur dioxid on stored fruit and the fungi causing 

 rots was studied. Apples and pears were naturally and artificially infected 

 with fungi, among which were Glceosporium fructigenum, Miicor stolonifcr, M. 

 piriformc, and Botrytis cinerca, after which the fruit was subjected to fumes 

 of sulphur dioxid. The treatment seemed without protective value, and in 

 liractice the author advises against its use, as the fruit was often injured and 

 in some cases made worthless by the fumigation and the fungi were not in the 

 least affected. 



Yellowing of citrus ti'ees, J. Muller {Agr. Jour. Cape Good Hope, SJi {1909), 

 No. 2, pp. tJf9-157, figs, i^).— The author states that for some time complaint has 

 been mtide that citrus trees were dying in South Africa. At first sight it was 

 suspected that root rot was the cause of the trouble, but ou examiuatiou it was 



