994 EXPERIMENT STATION RECORD. 



there is some variation from year 'to year tliere was more smut than 

 usual iu the oat crop tbrougliout the State, and, as usually occurs, the 

 highest percentage was found on plants grown from western rather than 

 home-grown seed. 



The occurrence of onion mildew in Vermont was reported late in 1895, 

 and experiments are to be conducted to ascertain the method by which 

 the fungus is cariied over from year to year and in what way it infects 

 the plants. • Some of these experiments, at the time of the publication 

 of the report, indicate that the spores are carried over in the soil and 

 infect the growing crop in that waj. It is 'bought probable that the 

 collection and burning in autumn of all the leaves from diseased plants 

 would ])revent the infection of the soil, and that onions could be grown 

 a second season with safety. 



A new Micrococcus of potatoes and the parasites of potato 

 starch grains, E. liozE {Compt. Bend, 123 {1890), Ko. 26, pp. 1323, 

 J32i). — The author reports having isolated from tubers of potatoes a 

 new micrococcus to which the name Micrococcus delacourianus is giveu. 

 The microorganism is from 1.5 to 2 ;/ in diameter, occurs in great abun- 

 dance, and is considered the cause of a diseased t-oudition called black 

 gangrene {(jangrene noire). The epidermis over the diseased areas is 

 wrinkled and somewhat brown. The tissue underneath is rather solid 

 but of a dark color. If placed under a bell jar and kept moist for a 

 few days numerous mucilaginous spherical masses appear which are 

 filled with the microorganism. 



Notes are also given on two parasites of starch grains: Amylotrogus 

 discoid et(s and A. ramulosus, mention of which has already been made 

 (E. S. R., 8, p. 607). 



In a subsequent note^ the author mentions the discovery of three 

 additional .species of Amylotrogus to which the \)Rmes A. filiform is, 

 A. lichenoides, and A. vittiformis have been given. Of these A. filifor- 

 mis penetrates the starch grain, as is the case with the first two species 

 mentioned in the first reference, while the last two confine their attack 

 to the surface. 



Action of certain chemicals on the germination of spores of 

 black rot, L. Rayaz and G. Guirand {Compt. Rend., 123 {1S96), No. 24, 

 pp. 108G-108S; also Rev. Scient., ser. d, 7 {1897), No. 1, p. ^5).— The 

 authors have investigated the effects of a large number of chemicals on 

 the germination of the si)ores of the black-rot fungus. The substances 

 were used in solutions of varying strength from 1: 1,000 to 1: 100,000. 

 In general it was found that acidity of cultures favored germination 

 while alkalinity, corresponding to 1 : 10,000 of sulphuric acid, completely 

 checked it. On this account, alkaline solutions have a much greater 

 efficiency when applied to plants than acid ones. It was further found 

 that copper solutions Avere less active against the black-rot fungus than 

 against mildew, and that zinc had practically the same action as copper. 

 Weak solutions of nickel favored the germination of the spores, and 



' Compt. Rend., 121 (1S97), No. 5, p. 248. 



