DISEASES OF PLANTS. 843 



spot of watermelons due to Glccosporium lagenarium, which is vei'y widely 

 spread in the Crimea ; and wheat rust caused by Puccinia glumarum, with par- 

 ticular reference to the possibility of its transmission with the seed. 



In testing various fungicides, it was found that a proprietary compound 

 known as Mortus was most effective against apple scab and American goose- 

 berry mildew {Sphccrothcca mors-uvcc). The composition of Mortus is un- 

 known, but chemical analysis showed the presence of sodium and arsenic, and 

 some evidence was obtained that the effectiveness of the compound is due to 

 the latter element. Laboratory, tests with germinating spores of Monilia 

 fructigena, S. humtili, Trichothecium roseum, Penicillium sp., and others showed 

 that germination was retarded in a solution of ^ gm. sodium arsenite in 3 

 liters of water, and that it ceased entirely in a solution of twice this strength. 

 More extended experiments are to be carried on in the future. 



Observations on parasitic fungi in the Province of Podolsk, M. E. Dobrov- 

 OL'sKii {Zhur. Boliezni East., No. 4-5 {1914), V- 13D; abs. in Mat. Mikol. i Fito- 

 patol. Ross., 1 {1915), No. 1, pp. 74, 75). — Among the fungi collected by the 

 author in the Province of Podolsk in 1912, some are reported on new hosts, 

 among which are Tilletia controversa on Triticnm vulgare, Ventiiria inwqualis 

 on Fyrus prnnifolia, and Rliytisma punctatum on Acer ginnale. The author 

 also describes Ascochyta cardiacm n. sp. from Leonurus cardiaca. 



[Report on plant diseases], F. A. Stockdale (In Summary of Investigations 

 Made During the Period Jamiary 1 to June 30, 1915. Manritins: Dept. Agr., 

 1915, pp. 1, 2). — Three manifestations are described from different localities of 

 what appears to be a physiological disease resulting in the production of a 

 gummy substance in the tissues of the sugar cane plant. The leaf and stem 

 disease of cassava due to Olaosporiuin manihotis has again been prevalent in 

 some .sections, local varieties suffering more than those recently introduced. 

 The local variety of pistachio appears to be more resistant than imported ones 

 to a leaf spotting disease caused by a species of Cercospora. 



Phytophthora infestans was common on potatoes and tomatoes in some locali- 

 ties late in June. Its control, where dews are heavy, appears to be more 

 difficult in this region than in Europe. Attempts are being made to hybridize 

 locally resistant varieties with standard European varieties of tomatoes. 



Du.ration of resistance of plants and insects to hot water {Rev. Sci. [Paris'\, 

 53 {1915), I-II, No. 17, pp. 405, 406).— In connection with the mention of tests on 

 the resistance of insects to hot water in view of the present high price of 

 chemicals, it is said to have been found by Gaston and Vermorel that grapevines 

 were uninjured by a hot water temperature of 45° C. (113° F.), but that young 

 leaves were killed by a temperature of 50° in 6 minutes and 52° in 1 minute. 



Burgundy mixture as a substitute for Bordeaux mixture, W. Nowell {Agr. 

 News [Barbados], 14 {1915), No. 355, p. 398). — Tlie difficulty experienced in 

 securing quicklime for Bordeaux mixture in some of the West Indies having 

 resulted in the employment of slaked or partly slaked lime in this application 

 and in the preparation therefrom of an inferior spray for fungicidal pui'poses, 

 attention has been directed to Burgundy mixture. This is said to have yielded 

 excellent results in experiments referred to, showing advantages even where 

 good lime is available. Several formulas are given, with directions for mixing 

 and testing. 



Fungicide experiments, 1914, G. P. Darnell-Smith {Agr. Gas. N. S. Wales, 

 26 {1915), No. 6, pp. 494, 495). — The results of these and pi'evious experiments 

 are claimed to show that the safest treatment thus far tested, as regards 

 germinability and freedom from bunt, is immersion of the seed wheat for three 

 minutes in 1.5 per cent copper sulphate solution and then for an equal period 

 In lime water. 



