754 EXPERIMENT STATION RECORD. [Vol.43 



nial as regards winterkilling and injury to trees and slirubs of all classes. The 



■ dry condition of the atmosphere was associated with a remarkable dryness and 



brittleness of the leaves. Other factors are briefly considered. Lists are given 



of trees and slirnbs grouped according to the amount of injury they sustained. 



Pliyllactinia corylea on oak leaves, E. Foex {Bui. Soc. Path. Vey. France, 

 6 {1919}, No. 6, pp. 151, 161-166). — From evidence here presented it is concluded 

 that some oaks in tlie forest near Lyons are attacked by both P. corylea and 

 Microsphwra. quercina. 



Parasites of plane trees in Nice, 1918, J. Cotte {Bui. Soc. Path. Veg. 

 France, 6 {1919), No. 3, pp. 63, 65-67). — In addition to certain animal parasites, 

 Gnomonia veneta {Glaosporlum nervisecmum) was noted as possibly connected 

 with Nectria cinnaburma in a disease indicated of plane trees. 



A walnut shell disease, R. Mirande {Bui. Soc. Path. Veg. France, 6 {1919), 

 No. 6, pp. Ill, 134-136, pi. 1). — Lesions, of considerable size in some cases, near 

 the apical portions of the shell in case of walnuts showed no sign of microorgan- 

 isms, and are considered as exemplifying failure in the process of lignitication, 

 possible causes of which are suggested. 



AVhite pine blister rust, J. H. Grisdale {Canada Expt. Farms Rpt. 1919, pp. 

 57, 58). — The author reports the results of scouting investigations to determine 

 the extent to which the white pine blister rust exists outside of Ontario and 

 Quebec. No disease was found in British Columbia, Manitoba, Saslvatchewan, 

 Northern Ontario, and New Bruns\Vick. The results seemed to indicate that the 

 disease is still confined to southern Ontario and Quebec. A number of experi- 

 mental control areas have been establislied to determine the possibility of pre- 

 venting the occurrence of the blister rust in pine woodlots, and observations have 

 shown that infection will not readily cross a distance of 500 yds. An attempt was 

 made to determine the amount of damage done to pines by a sui'vey of a number 

 of woodlots, and out of 11,279 trees in 22 woodlots in the Niagara Peninsula, 

 only 2.3 per cent were found infected. On account of tlie comparatively small 

 amount of infection found, it is hoped that under favorable conditions the losses 

 from the disease may be kept so U,w that the growing of white pine on a com- 

 mercial basis will be possible. The factors concerned in tlie infection of pines 

 are lield to be nearness of cultivated Ribes, eispecially black currants, the number 

 of wild currants present, and moisture of the situation. 



Some experiments were carried on to determine the effect of ultraviolet light 

 and sunlight on the recidiospores and uredospores of the blister rust fungus. 

 It was found that exposure for 2i minutes to ultraviolet light was fatal to the 

 germinating capacity of the spores, but that when exposed to sunlight under 

 glass they survived exposures as long as 5 hours. A determination was made 

 on the rate of fall of fecidiospores of the rust fungus, and it was found that in 

 still air the secidiospores dropped a distance of 8 ft. in a little over 7 minutes. 

 This rate of motion is considered important as indicating the rapidity by wliich 

 the spores can be carried by wind to a considerable distance. 



Observations on the relation of insects to the dissemination of Cronar- 

 tium ribicola, W. H. Snell {Phytopathology, 9 {1919), No. 10, pp. 451-46-^).— 

 Results are given of cooperative investigations carried out with the Bureau 

 of Plant Industry and the Bureau of Entomology, U. S. Department of Agri- 

 cultui'e, on the relation of spread of insects to the spread of plant diseases. A 

 large number of species of insects, cliiefly beetles, were found on or near 

 blister rust lesions of the white pine, bearing aeciospores in varying quantities. 

 One beetle {Serica sericea) was collected feeding upon a red currant bush and 

 bore aeciospores on its body. Many species of insects were found to bear 

 urediuiospores from Infected leaves, some in large quantities. Inoculations 



