854 EXPERIMENT STATION KECOED. 



hydrography. The weather influences only the date of the appearance. The 

 disease appears first not in regions of greatest warmtli and heaviest rainfall, 

 but in those of extensive sandy areas and tracts liable to flooding. The disease 

 appears later, however, on cold soils, despite abundance of superficial water 

 and favorable weather. After an April with regular temperature and without 

 white frosts the first outbreak occurs about IMay 15. 



Besistance of hybrid direct-bearer vines to mildew, E. Pee-Laby (Vie Agr. 

 et Riirale, 3 (.1914), No. 22, pp. 603-605; abs. in Internat. Inst. Agr. [Rome], Mo. 

 Bui. Agr. Intel, and Plant Diseases, 5 (1914), No. 7, p. 962). — Lists are given, 

 bused upon tests made, of grape hybrids which require for safety in moderate 

 mildew years no spraying with copper sulphate. Mention is made of other de- 

 sirable hybrids not yet conclusively tested but probably resistant to mildew. 



Rose diseases (Inst. Phytopath. Wageningen, Ylugsclir. 12 (1914), PP- 1-3). — 

 In addition to some animal parasites, mildew (SphwrotUcca pannosa), rust 

 (Phragmidiiim subcorticlum), and false mildew (Peronospora sparsa) of rose 

 are discussed, with treatments as recommended. 



Field studies on the dissemination and growth of the chestnut blight 

 fungus, P. J. Anderson and D. C. Babcock (Penn. Chestnut Tree Blight Com. 

 Bui. 3 (1912), pp. 45, pis. 14). — This report refers to work carried out chiefly at 

 Charter Oak and Mt. Gretna, Pa. 



Tests for infection gave positive results in all but three of eleven kinds of 

 wounds. Inoculation of natural insect holes in no case to date produced a 

 canker, but it is believed that any wound in the bark may furnish an entrance 

 for the fungus. 



Among the known or suspected means of dissemination are nursery ship- 

 ments, grafts, shipments of timber and fire wood (moisture and shade assist- 

 ing), dead leaves, burs, bark, tools, wind, and rain. The agency of birds has 

 not been established. Ants may possibly carry the spores. Experiments in- 

 dicate that a beetle (Leptostylus maculata) eats the spores, and that it may be 

 really beneficial. 



The fungus grows much more rapidly in dead than in living tissue. Spores 

 are very long lived and quickly become active upon being wetted. Conidia can 

 produce infection after being kept dry in the spore-horn stage for 19 weeks. 

 The greatest rate of spread in the cankered spots was obtained during July 

 and August. 



A fungus, in all outward appearance the same as Endothia parasitica, is re- 

 ported on Quercus velutina, Q. alba, Q. primis, Rhus tijphina, Acer rubrimi, and 

 Carya ovata, and it was isolated from all but Q. prinus. The chestnut blight 

 fungus was repeatedly grown on sterilized twigs of all of the above and on 

 Castanea dentata, Q. macrocarpa, Q. rtihra, Q. coccinea, Nyssa sylvatica, Lirio- 

 dcndron tuUpifera, and Juglans nigra, producing pycnidia regardless of the 

 mode of inoculation. The growth on all oaks, on sour gum, and on sumac was 

 as rapid and vigorous as on chestnut twigs. The fungus appears to be a M'eak 

 parasite on white oak, chestnut oak, and sumac. 



The anatomical and physiological conditions of chestnut branches attacked 

 by the ink disease, L. Petri (Atti R. Accad. Lincei, Rend. CI. Sci. Fis., Mat. e 

 Nat., 5. ser., 23 (1914), I, No. 5, pp. 363-369; abs. in Internat. Inst. Agr. [Rome], 

 Mo. Bui. Agr. Intel, and Plant Diseases, 5 (1914), No. 7, p. 964). — The author 

 has followed up previous observations on the part played by Coryneum modo- 

 nium in producing black canker of chestnut (E. S. II., 29, p. 156; 30, p. 52). 



In branches three to nine years old collected at the end of November, 1913, 

 various differences were found between the healthy and the diseased branches. 

 It seems that the earliest and most serious irregularity takes place In the mia- 



