DISEASES OF PLANTS, 647 



E. parasiiica may feed to some extent on tannin. Specially prepared pure 

 tannin extracts were less toxic to tlie funf,'us than the commercial tannin. Color- 

 ing materials which are usually estimated as tannins were toxic. Tannic acid 

 is toxic to many parasitic funsi, but there are other compounds associated with 

 it that are more toxic and may be more iniyiorlant in the economy of the host 

 plant. 



A new filbert disease in Oregon, II. P. Barss (Oregon Sta. Bien. Crop Pest 

 and Hart. Rpt. J913-1J,. pp. 21S-223, figs. 9). — A description is given of a serious 

 filbert disea.se, which is said to be prevalent in western Oregon, that is charac- 

 terized by the blighting of the buds and new shoots, spotting of the leave's, 

 girdling and brealving down of smaller brandies, and the formation of cankers 

 on the larger branches and trunks. Bacteria have been associated with this 

 disease, but while they are believed to cause it inoculation experiments have 

 not completely demonstrated the relation that they bear to the trouble. Cer- 

 tain varieties of filberts were found more resistant to the disease than others, 

 and for prevention and control the author recommends the growing of filberts 

 in tree form, selecting resistant varieties, and spraying throughout the spring 

 to reduce the number of infections. 



Beport on cultures with foliaceous species of Periderniiuni on pine 

 made in 1914, G. G. Hedgcock and W. II. Long (Ahs. in Science, n. .scr., Jfl 

 (1915), No. lOJfS, p. 111). — A summary is given of experiments with P. acicohim, 

 P. carneiiin, P. clclicaliihim, P. inconspicuiim, P. intermedium, and P. montaniim, 

 all taken from species of pine. A total of 712 inoculations were made with 

 these species, and with the species of Coleosporium with which they were asso- 

 ciated as alternate forms. 



The results of the experiments indicate that at least four of these species 

 and the related species of Coleosporium lielong to a single polymorphic species, 

 and that the transfer from one herbaceous host to another is accomplished 

 through the fecial forms in the pines. 



Injury by disinfectants to seeds and roots in sandy soils, C. Hartley ( U. S. 

 Dept. Agr. Bui. 169 (1915), pp. 35, pi. 1. figs. 2). — ^The results of several seasons' 

 investigations on the control of damping-off of pine seedlings are given, a pre- 

 liminary report of which has already been noted (E. S. R., 31, p. 647). 



The author found that sulphuric, hydrochloric, and nitric acids, and copper 

 sulphate used in disinfection of seed-bed soil caused injury to the roots of pine 

 seedlings and prevented the development of many species of weeds. Many of 

 the injured seedlings later resumed root growth and recovered. The injury is 

 considered due to the concentration of the disinfectant in the surface soil, due 

 to the capillary rise of the soil solution and the evaporation of water from 

 the soil surface. 



It was found in a sandy soil that all injury could be prevented by frequent 

 watering during a germinating period. It could also be prevented by an addi- 

 tion of lime shortly after treating the soil with disinfectant. The use of lime, 

 while undesirable in the case of growing pine seedlings, is believed to be the 

 only way in which injury to angiospermous .seedlings can be prevented. Acids 

 also, it was found, could be applied to seed beds at the time of sowing without 

 injury to dormant pine seed. Formaldehyde and corrosive sublimate solution 

 in sufficient strength for disinfection should be used several days before sowing 

 the seed, as they are liable to kill dormant pine seed in the soil. Formaldehyde 

 applied at or before seed sowing was never found to cause the injury to germi- 

 nating pine seed that was caused by acids and salts, 



