IQlT^l DISEASES OF PLANTS. 749 



in England this year, it is stated that, while hydrogen peroxid proves efficacious 

 in this connection, it is unstable, deteriorating if kept. Corrosive sublimate of 

 0.1 per cent strength, used to soak the seed for half an hour (after softening 

 for an equal period in warm water), is very successful. If infection appears on 

 careful daily scrutiny during the growth of the plant, Bordeaux mixture should 

 be used, after removal of the leaves most affected. As spores of the fungus 

 (Septoria petroselini apii) do not survive for more than two or three years, 

 seed of such age is fairly safe, if germinable. 



A collar disease of pea, F. Gu^guen (Ami. Serv. Epiphyties, Mem. et Rap., 

 2 (1913), pp. 302-309, figs. 15).— The author reports a study of a pea disease in 

 the neighborhood of Paris, ascribed to a Fusariuni said to have been considered 

 by van Hall (E. S. R., 15, p. 375) as the conidial form of Neocosmospora vas- 

 infecta pisi. He discusses the character of the lesions, the microscopic aspects 

 of the fungus, its culture, and its capacity for infection. 



The reappearance of Phytophthora infestans during the growth of the 

 potato plant, J. Eriksson (Compt. Rend. Acad. Sci. [Paris], 16S (1916), No. 4> 

 pp. 97-100). — Giving the results of recent studies, the author states that the 

 blight fungus, P. infestans, does not appear for three or four months after plant- 

 ing, or until about the time when the blooms appear. In Sweden, the time of 

 the primary outbreak in open fields may vary from the middle of July to the 

 first of September, according to meteorological conditions. Moist weather 

 favors the disease, whicii very quickly becomes general. The spots appear to 

 be independent of each other. Under glass, if the tubers are planted in Janu- 

 ary the blight may appear by the middle of April, when the plants are as fully 

 developed as those in the open fields late in summer, causing some check to 

 growth and some deformation of the plants. 



The changes occurring within the first day in the development of the parasitic 

 organism, from the supposedly symbiotic or mycoplasmic stage, are described 

 in some detail. 



A Melanconiuni pai-asitic on the tomato, W. H. Tisdale (Phytopathology, 

 6 (1916), No. 5, pp. 390-394, figs. S). — A more detailed account is given of a 

 disease of tomatoes which has been previously noted (E. S. R., 36, p. 49). 



In connection with this study, a Melanconium morphologically identical with 

 the tomato parasite was found growing saprophytically on onions in the same 

 greenhouse. The specific identity of the fungus has not been determined, but 

 should the disease become of economic importance, it is expected that further 

 study of the organism would be made. 



The results of the experiments show that the fungus grows readily on tomato 

 fruits when introduced through wounds, and that it is also able to attack unin- 

 jured fruits if the moisture conditions are suitable for germination and growth. 

 There is said to be some indication that the disease Is spread in the greenhouse 

 by white flies. 



A parasitic saccharomycete of the tomato, A. Schneidek (Phytopathology, 

 6 (1916), No. 5, pp. 395-S99, figs. 4).— The author reports having isolated, from 

 tomatoes obtained in a restaurant in Berkeley, Oal., an organism which proved 

 to be a saccharomycetous ascomycete. The affected tomato presented a slightly 

 depressed area of about 2 cm. in diameter and of a peculiar dull, reddish-brown 

 color. The epidermal tissue was somewhat shriveled, but the hypodermal tissue 

 as well as the parenchymatous tissue underneath appeared nearly normal. 



The fungus is a true parasite, as it develops in and on living tissues but will 

 not develop in the presence of decay. Upon the death of the tomato tissues, 

 the organism at once enters upon a very active spore formation. 



A note on Phytophthora infestans occurring on tomatoes, S. P. Wiltshiee 

 (JJitiv. Bristol, Ann. Rpt. Agr. and Hort. Research Sta., 1915, pp. 92, 93). — A 



