DISEASES OF PLANTS. 247 



heart leaves. The spots bearing pycnidia usually appear during July and 

 August on old or yellowing leaves near the ground, the pycnospores being dis- 

 seminated by such agencies as beet balls, wind, irrigation water, insects, and 

 manure. 



P. hetcc in leaf tissue is killed in * hour by dry heat of 80 to 90° C, in 3 

 months by storage in boxes of soil exposed to outdoor conditions, in 5 to 8 

 months by burial in the ground, but apparently in 2 mouths by ensiling. A 

 period of one year seems sufficient to eliminate P. hctm from an infected 

 field, with the possible exception of the mycelium in a sugar beet root or mother 

 beet stalk. No evidence of a perfect stage of the organism was found. 



Blossom-end rot of tomatoes, C. Brooks {ISIew Hampshire Sta. Sci. Contrib. 

 8 {I91.'t). pp. 345-374, i)ls. 3, figs. 5). — A reprint of an article previously noted 

 (E. S. R., 32, p. 343). 



Resistance to Cladosporium fulvum in tomato varieties, J. B. S. Norton 

 {Ahs. in Phi/topathologn, 4 {1914), No. 6, p. 39S). — The author reports a study 

 of 25G plants of 14 varieties of tomato grown in the greenhouse in the early 

 spring of 1914, nearly all of which were badly affected with Cladosporium, 

 except Stone and Sterling Castle, which were practically immune. 



Loss from mosaic disease of tomato, J. B. S. Norton (Abs. in Phytopathol- 

 (^9V, 4 {1914), No. 6, p. 398). — The author reports the extensive occurrence of a 

 mosaic disease of tomato in Maryland. Greenhouse experiments showed that 

 the plants first attacked by the disease bore scarcely less weight of friiit than 

 those which remained healthj^ longest, but healthy plants set 33 per cent more 

 fruit than infected ones. 



Orchard experiments in 1914, M. T. Cook and G. W. Martin {Ahs. in Phyto- 

 pathology, 4 {1914), No. 6, p. 394)- — A brief account is given of experiments 

 carried on by the New Jersey Experiment Stations, in which finely divided sul- 

 phur was applied to peach orchards. 



The results indicate that scab was successfully controlled, although some of 

 the trees were partly defoliated. On apple trees finely divided sulphur did not 

 give as good results as lime sul])hur. 



Hosts of brown rot Sclerotinia, J. S. Norton {Abs. in Phytopathology, 4 

 {1914), No. 6, p. 398). — Inoculation experiments with conidia of the common 

 brown rot fungus of orchard fruits have shown that conidia developed on the 

 cherry, wild-goose plum, blackberry, Japanese plum. Damson plum, green corn, 

 pear, peach, apple, wild black cherry, strawberry, crab ai)i)le, Crataegus, Pyrus 

 bctulifolia, dried prune, peach, apricot, and raisin. About 50 species of plants, 

 including Rosa, Amelanchier, Rubiis occidcntalis, P. a rb lit i folia, and Cydonia 

 japonica, showe<l no outward sign of infection. 



Apple fruit spot and quince blotch, C. Brooks and Caroline A. Black {New 

 Hampshire Sta. Sci. Contrib. 5 {1912), pp. 63-72, pis. 2). — A reprint of an article 

 previously noted (E. S. R., 27, p. 652). 



Apple leaf spot, C. Brooks and Margarkt DeMeritt {New Hampshire Sta. 

 Sci. Contrib. 6 {1912), pp. 181-190, pi. 1). — A reprint of an article previously 

 noted (E. S. R., 28, p. 548). 



Apple rust or cedar rust in West Virg'inia, N. J. Giddings and A. Berg 

 {West Virginia Sta. Cire. 15 {1915), pp. 16, figs. 7). — Discussing briefly the 

 life history of the apple and cedar rust fungus, the author describes attempts 

 at conti'ol by preventive treatment. 



Control by use of sprays, while possible, seems impracticable for the com- 

 mercial orchardist. Destruction of cedar trees seems effective if complete, and 

 practicable, costing less than 48 cts. per acre over 1.113 acres experimented 

 upon. It is believed that the cedar-free area should cover a radius of at least 

 a mile around an orchard. 



