146 EXPERIMENT STATION EECORD. [Vol. 3G 



In connection with studies of disease resistance, a variety of emmer has been 

 found wliich is not subject to rust attack, while anotlier was only slightly at- 

 tacked. A number of Fi and F2 generations of wheat hybrids are being tested 

 for resistance to rust (Puccinia graminis tritici). Observations made on 119 

 varieties of winter wheat showed infection vrith leaf rust (P. rubigo-vera 

 tritici) varying from 5 to 90 per cent. Histological studies are said to be in 

 progress to determine the cause of immunity to smut in milo maize and of 

 susceptibility to this smut in other sorghums. Studies are being conducted on 

 the life habits of the smut on maize and on the varietal resistance due to 

 environmental conditions or to specific characteristics in the host. 



Rye smut, E. C. Stakman and M. N. Levine {Minnesota Sta. Bui. 160 {1916), 

 pp. 3-19, figs. 6). — A disease of rye variously known as stem smut, stalk smut, 

 and stripe smut, due to the fungus Vrocystis occulta, is described. The disease 

 is said to cause serious losses in Minnesota, in some localities from 5 to 40 

 per cent of the plants in the field being infected. The spores are said to live 

 over in the seed or soil, and seed treatment with formaldehyde and planting in 

 clean soil are recommended as control measures. Rotation of crops is advised 

 in order that the fungus may be eliminated from the soil. 



The determination of ustilaginous spores in flour, bran, and cereals, G. 

 Bredemann {Landw. Vers. Stat., 87 {1915), No. 4-5, pp. 2^1-250) .—The author 

 reports further analytical data obtained by the method previously noted 

 (E. S. R., 26, p. 408) and concludes that it yields truer and more reliable, not 

 only relative but positive, results than the procedure described by Groh 

 (E. S. R,. 27, p. 310). 



The quantitative determination of smut spores in bran, G. Bredemann 

 {Arch. Chem. u. Mikros., 8 {1915), No. Jt, pp. 87-95). — Tests described are con- 

 sidered to prove the reliability of methods for spore estimation employed by 

 the author (E. S. R., 26, p. 408). 



The Texas root rot fung'us and its conidial stage, B. M. Duggae {Ann. 

 Missouri Bot. Oard., 3 {1916), No. 1, pp. 11-23, figs. 5). — Having made a study 

 of the cotton root rot which is common in many portions of Texas, the author 

 describes the causal organism, which, with some modifications of form and 

 habit, attacks also an unknown but probably large number of native plants in 

 that State, under the new combination PhymatotricMmi omnivorum, i-etaining 

 the specific name applied thereto by Shear (E. S. R., 19, p. 446). 



Spong'ospora on the roots of the potato and on seven other new hosts, 

 I. E. Melhits and J. Rosenbaum {Abs. in Fhytopathologg, 6 {1916), No. 1, p. 

 108). — This fungus, which is commonly considered to infect the tubers, the 

 authors found in greenhouse experiments to involve all the underground parts 

 of the plants. Later, this condition was found to prevail in the field also. 



The authors' investigations have shown that Spongospora, in addition to 

 infecting the potato, attacks the tomato and six species of Solanum, Sf. commer- 

 soni, 8. ciliatum, 8. marginatum, 8. mammosum, 8. hwmotocladum, and S. 

 tvarscewiezii. 



Meteorology and late blight of potatoes, C. R. Orton {Abs. in Phyto- 

 pathology, 6 {1916), No. 1, p. 107). — From a study of the meteorological condi- 

 tions in connection with the late blight of potatoes at the Pennsylvania Experi- 

 ment Station, the author claims that precipitation alone has little if any bear- 

 ing on the problem. Atmospheric temperatures alone or when correlated with 

 precipitation do not appear to have much relation to the outbreak of disease. 

 Humidity and soil temperature are believed to bear directly upon the subject. 



A Fusarium tuber and stem rot of potato, R. J. Haskell {Abs. in Phyto- 

 pathology, 6 {1916), No. 1, pp. 106, 107). — The author reports having isolated 

 from the fibrovascular bundles of potato tubers a Fusarium which produces a 



