1919] DISEASES OF PLANTS. 49 



the author on the morphology, probable relationships, and habits of specimens 

 of fungi collected on coffee leaves at Mayagucz. P. R., in August, 1915, and -May, 

 1917. The author describes C. koleroga on coffee, C. vagum oil various plants 

 (also on other bodies), and C. sti rensii (which is newly named) on apple, pear, 

 quince, and Codiseum. It is stated that many fungi in the Tropics have the 

 thread blight habit of growth. 



Sclerotinia diseases (Jour. Bd. Agr. [London], 23 (1911), Xo. 11, pp. 1095- 

 1908, pis. 2). — The causes of loss here discussed as due to Sclerotinia sclero- 

 tiorum arc stalk disease of potato (said to be widely distributed and destructive 

 in England and Scotland and to cause serious damage in the western part of 

 Ireland), and diseases of tomato, artichoke, sunflower, bean, squash, cucumber, 

 carrot, and turnip. In all cases the sclerotia, which are produced in abundance, 

 fall to the ground or remain dormant in the dead tissues until spring. The 

 disease seldom appears before midsummer, being favored by warm, damp 

 weather. Preventive measures include sterilization of the soil with steam, a 

 3-year rotation, late planting, and in case of potato, careful selection of tubers' 



In be stored for seed. 



The use of formaldehyde to control cereal smuts, G. H. Coons {Michigan 

 Sta. Quart. Bui, 1 (1918), No. 1, pp. 11-14).— The concentrated and dilute 

 methods of treating oats and wheat with formaldehyde for the control of smut 

 are briefly described, and the necessity of care in their use is emphasized. 



The stinking smut of wheat, F. D. Heald (Washington Sta. Popular Bid. 

 115 (1918), pp. 3-lJf, fig. 1). — A popular account is given of the wheat smut 

 which occurs in the Palouse region of eastern Washington with suggestions 

 for its control. 



Under present conditions it is considered impossible to produce absolutely 

 smut-free wheat, since wind-blown spores reach uninfected fields. Seed treat- 

 ment alone is not effective on account of the general and wide dissemination of 

 smut spores during the thrashing season. Seed treatment is generally ef- 

 fective for spring wheat, since wind-blown spores do not survive the winter. 

 Experimental seedings have shown that either early or late plantings are 

 either entirely free from smut or show a low percentage of infection. 



The installation of exhaust fans in connection with thrashing machines is 

 recommended as a means of preventing fires in separators, improving the quality 

 of the wheat, and reducing the amount of wind-blown smut. 



Corn root rot and wheat scab, G. N. Hoffeb, A. G. Johnson, and D. Ataxa- 

 soii {Jour. Agr. Research [U. S.I, U (1918), No. IS, pp. 611, 612).— In a pre- 

 liminary contribution from the Bureau of Plant Industry, U. S. Department of 

 Agriculture, the authors call attention to investigations of rots of the root, 

 stalk, and ear of Indian corn, from which there appears to be a relation be- 

 tween the occurrence of these rots and the scab of wheat. Field observa- 

 tions have shown a conspicuously greater abundance of wheat scab in fields 

 where wheat was grown Immediately following corn which had been affected 

 with the Fusarium rot of root and stalk. This was specially true in Indiana, 

 and a similar condition was noted in Wisconsiu. In both States, where spring 

 wheat was grown immediately following a corn crop, an abundant development 

 of perithecia of Oibberella spp. was found on the old cornstalks remaining in 

 the field. Water suspensions of the ascospores found on the cornstalks gave 

 positive results when inoculated on wheat heads, the appearance of the heads 

 infected artificially being identical with that of those naturally infected with 

 scab. 



The authors suggest that, in view of their preliminary findings a crop rota- 

 tion should be adopted in which wheat following diseased corn should be avoided. 



