DISEASES OF PLANTS. 153 



Orobanche cumana on sunflower, A. Mal'tsev (Trudy Biltro Prikl. Bot. 

 (Bui. Angcw. Bot.), 6 (1913), No. 2, pp. 111-120).— The author reports the 

 parasitism of tbe above species of Orobanche on the sunflower (Helianthus 

 annuus). The spread of the parasite is said to be restricted somewhat by 

 Phytomyza orohanchia. 



California thistle rust, A. H. Cockayne (Jour. Agr. [New Zeal.], 8 (1914), 

 No. 1, pp. 50-53, fig. 1). — A description is given of Puccinia suaveolens, which is 

 said to have become established m New Zealand where it is restricted to the 

 California or Canada thistle (Cnicus arvensis) and the cornflower (Centaurea 

 cyanus). The fnngus is thought to be probably of some value in combating the 

 thistle, but success in its spread will depend upon the ability to obtain artificial 

 infections, and for this purpose studies are needed to determine the proper stage 

 in the growth of the plant. The author believes that the best time for success- 

 ful inoculation would be while the growth of healthy plants is quite young. 



The symptoms of chestnut tree blight and a brief description of the blight 

 fungus, F. D. Heald (Penn. Chestnut Tree Blight Com. Bui. 5 (1913), pp. 15, 

 pis. 16). — The author has given a description of the chestnut blight, the fungus 

 causing it, symptoms of the disease, effects, methods of spread, etc. 



Longevity of pycnospores of the chestnut blight fungus in soil, F. D. 

 Heald and M. W. Gardner (U. S. Dept. Agr., Jour. Agr. Research, 2 (1914), 

 No. 1, pp. 67-75; al)s. in Phytopathology, 4 (1914), No. 1, pp. 51, 52). — A report 

 is given of investigations made to determine the power of resistance of the 

 pycnospores of the chestnut blight fungus to desiccation in the soil under field 

 conditions during the intervals between rains and during a prolonged period of 

 drying in the laboratory. 



In the field test samples of soils taken from bases of diseased trees after a 

 rain and after 13 days' drying gave from 84.000 to 2,412,000 viable spores per 

 gram of soil. When dried in the laboratory there was a gradual decrease in 

 the viable spores, the longevity limit varying from 54 to 119 days. 



Pine rust and its transmission, Haack (Ztschr. Forst u. Jagdio., 46 (1914), 

 No. 1, pp. 3-46, pis. 2, fig. 1). — This is an account of studies continued from 

 1906 to 1913 at Eberswalde on questions connected with Peridermium pint. 



This disease is said to appear most commonly in young foliage-bearing 

 branches, each center being due apparently to a separate infection. The fungus 

 is said to proceed directly from pine to pine by means of recidiospores, requiring 

 no intermediate host and infection occurring mostly between May 15 and July 1. 

 Injuries to the young vegetation are thought to aid greatly the attack. Some 

 trees appeared to be especially susceptible, some to be nearly immune to the 

 fungus. Shoots may live some time after being seriously attacked. 



Thoroughgoing removal of affected parts in case of young trees and cutting 

 out badly diseased older trees are insisted upon as means of greatly minimizing 

 the damage, which otherwise is considerable. 



An unusual case of electrical injury to street trees, G. A. Cromie (ScJ. 

 Amer. Sup., 77 (1914), No. 1985, pp. 36, 37, figs. 5).— Several examples are dis- 

 cussed of injury to trees by electrical currents, especially in one case following a 

 change of the negative or return current to the overhead wire. Insulation 

 decreased the injury done. Chemical analysis showed traces of copper and 

 zinc in sections of wood taken some distance from the point of contact with the 

 wire containing both these metals, which was always found to be partly eaten 

 away at that point. 



Notes on the preparation of insecticides and fungicides, V. Vermorel and 

 E. Dantony (Notes sur les Preparations Insecticides, Fongicides et BouilUes 

 Mouillantes. ilontpellicr and Villefranche [1914], pp. 58). — In this publication 



