1917] DISEASES OF PLANTS. 747 



requirements which would establish this claim. The ability of these rusts to 

 exist in the absence of an alternate host plant is indicated, but this alone does 

 not constitute autcecism nor facultative hetercecism. 



Studies of the genus Phytophthora, J. Rosenbaum {U. S. Dept. Agr., Jour. 

 Agr. Research, 8 (,1911), No. 7, pp. 233-276, pis. 7, figs. 13; Proc. Nat. Acad. 

 Sci., 3 {1917), No. 3, pp. 159-163) .—Basea on cultural and other studies of 11 

 of the 13 described species of Phytophthora, a tentative key is presented for 

 the identification of the species. 



Mechanism of tumor growth in crown gall, E. F. Smith {U. S. Dept. Agr., 

 Jour. Agr. Research, 8 (1917), No. 5, pp. 165-188, pis. 62).— A detailed account 

 is given of experiments pi'eviously reported (E. S. R., 36, p. 46), with sugges- 

 tions as to what is believed to be the proximate cause of the abnormal cell 

 proliferation in crown gall. The experiments described are considered to have 

 an important bearing not only on the production of crown gall and other 

 tumors in plants but also on the origin of animal tumors. 



The author believes that in the local osmotic action (possibly, in some stages, 

 chemical action also) of various substances thrown into cells and diffusing 

 from them in all directions, as the result of the metabolism of a feeble intra- 

 cellular parasite or symbiont together with the resultant counter movements 

 of water and food supply, there is, in crown gall at least and presumptively 

 also in animal neoplasms, an explanation of tumor growth. 



Intoxicating bread, N. A. Naumov {Elin. Zeml. [Russia], Trudy Biuro Milcol. 

 i Fitopatol., Uchen. Kom., No. 12 (1916), pp. 216, pis. 8, fig. 1). — This publica- 

 tion represents a further progress report of work on the disease of grain 

 called " drunk bi-ead " (E. S. R.. 35, p. 845), 



The author has made extensive studies of this disease, especially the relation 

 of the causal organisms to the hosts, their biology, and possible control meas- 

 ures. It is definitely stated that this trouble of cereals is due to the activities 

 of two species of Fusarium, F. roseum and F. suhulatum, which attack rye, 

 wheat, oats, and barley, not infrequently in quite alarming proportions, as much 

 as 88 per cent of infection having been observed on barley in 1912. Infected 

 seed and infected soil are the chief sources of the disease, while humidity and 

 high temperature are the main factors in the spread of the epidemic. Diseased 

 seed is recognized by the presence of the fungus mycelium in the grains. Posi- 

 tive results were obtained in artificial inoculations of soil, seedlings, and 

 heads with conidia and ascospores and also in artificial Inoculations of soil 

 and shoots with the mycelium. 



If the infected grain is stored under ordinary conditions for a period of 

 three years, the mycelium completely loses its vitality. Dry heat for 24 hours 

 at 66° C. (150.8° F.) for rye and at 60° for wheat, oats, and barley, while with- 

 out effect on the vitality of the seed, kills or at least greatly weakens the 

 fungus mycelium imbedded in the grains. Other control measures recom- 

 mended are seed selection, general sanitation, and proper crop rotation. Soak- 

 ing of the affected seed in various fungicides was not found to be efficient, 

 except when the spores or the mycelium of the parasites were present on the 

 surface of the grains. 



Glume rust of wheat, P. Berthault (Jour. Agr. Prat., n. ser., 29 (1916), 

 No. 15, pp. 256, 257). — An unusually severe outbreak of glume rust on wheat 

 is noted as causing much loss to the crop of 1916. Several known cereal rust 

 fungi, their modes of propagation, and protection therefrom are discussed. 



Crown gall of alfalfa in France, G. Arnatjd (Jour. Agr. Prat., n. ser., 29 

 (1916), No. 17, pp. 291, 292, fig. 1).—A description is given of alfalfa crown 

 gall and the mode of development and propagation of the causal fungus 

 (Urophlyctis alfalfa;), with a short account of the appearance of this disease 



