548 EXPERIMENT STATION BECORD. 



destructive to onions in parts of Australia. The experiments consisted of the 

 application of various chemicals to the soil, but while some of them destroyed 

 the living nematodes, they were not efficient in liilling the eggs. The treatments 

 were both laborious and expensive and can not be recommended on a large scale. 



Where the onions were started from seed in small beds of sterilized soil and 

 transplanted the plants were not attacked by nematodes unless the bulbs were 

 injured in the process of transplanting. 



Certain diseases of Maine potatoes and their relation to the seed trade, 

 W, J, Morse (Maine Sta. Doc. 375, pp. 12). — On account of the large and 

 rapidly growing demand for Maine seed potatoes for use in the Southern States, 

 the author calls attention to the principal characteristics for the determination 

 from the seed tubers of four important potato diseases (late blight, scab, black- 

 leg, and the Fusarium dry rot of the tuber) which seem to be distributed by 

 infected seed tubers, and suggests precautions and remedies for disinfecting the 

 tubers and preventing the dissemination of these diseases. 



It is claimed that diseases capable of being carried by the tubers are no more 

 common in Maine than in other States of similar climatic conditions, and that 

 none is of such a nature but that its transference by this means can be pre- 

 vented by discarding all unsound or diseased tubers and disinfecting the re- 

 mainder before planting. 



Corky scab of the potato, I. B. P, Evans (Transvaal Agr. Jour., 8 (1910), No. 

 31, pp. Ji(!2, Ji63, pi. 1). — A description is given of the corky scab of the potato, 

 due to Sporigospora scabies, with suggestions for the prevention of the disease. 



Experiments with three tobacco diseases, H. Jensen (Jaarb. Dept. Landb. 

 Nederland. Indie, 1908, pp. 100-101, pi. 2).— The inoculation of healthy tobacco 

 roots with a solution of the gum or slime from a plant attacked by gummosis 

 produced this disease in the roots thus inoculated, but if the plants were sound 

 and in a vigorous growing condition the disease rarely spread beyond the original 

 area of infection or to adjacent healthy plants. It is claimed that the best 

 means of control is by keeping the tobacco plants in a vigorous growing condi- 

 tion, as sound, healthy plants were found to be very resistant to this disease. 

 As a result of experiments conducted with Phytophthora it is stated that the 

 spores of this fungus can live for two years in the soil and are capable of 

 infecting tobacco grown on such land during that time. By cultures and micro- 

 scopic examination the black or leaf spot disease of tobacco was shown to be 

 caused by Cercospora nieotianff. 



Root diseases caused by Armillaria mellea in the Puget Sound country, 

 W. H. Lawrence (Washington Sta. Bui. 3, spec, ser., 1910, pp. 3-16, figs. 5). — 

 A popular discussion is given of this fungus, its nature, the injuries caused by 

 it, the distribution and means of identifying the disease, and the methods of 

 combating it. 



The bitter rot (Gloeosporium) of apples, R. Laubert (Dent. Obstbau Zig., 

 1910, No. l.'f, pp. 175-179, figs. 2). — A general discussion is given of the charac- 

 teristics, cause, and methods of control of this disease and of its gradual dis- 

 semination throughout Germany. 



A canker of apple trees caused by the brown rot fungus, E. S. Salmon 

 (Gard. Chron., S. ser., 1,7 (1910), No. 1221, p. 327, figs. 3).— Attention is called 

 to the development on the branches of apple trees of cankers caused by the 

 brown rot fungus (Sclerotinia fructigena). These cankers may be formed either 

 by the mycelium in a mummified apple, which in drying has become glued to the 

 branch, growing from the diseased apple into the branch, or the mycelium may 

 directly invade the wood from the base of a dead fruit spur which has been 

 killed by the fungus. 



