750 EXPERIMENT STATION RECORD. [Vol. 37 



remained free from infection, while all the others gave percentages of infection 

 ranging from less than 1 to 31. 



Inoculation experiments with bunt {Tilletia fat ens) on 15 common varieties 

 of wheat gave infection in all ca.ses, the amount ranging from 8.3 to 62.8 per 

 cent. The effect of date of planting on amount of infection was also tested, 

 planting being made from October 2 to October 30, and it was found that seed 

 planted latest in the year gave the highest degree of infection. 



Other infection experiments are reported with oat smuts (Ustilago avente and 

 U. levis), 38 varieties belonging to 10 species of Avena being inoculated with 

 spores of both smuts. Most of the hosts became infected, the percentage of in- 

 fection varying from less than 2 to more than 88. A. barbata, A. bret'W. and 

 A. strigosa remained entirely free from the smuts. Of the common varieties of 

 oats, a few, notably Burt and Early Ripe, remained praeiically free from 

 infection. 



Ecological observations on Ustilago zeae. A. A. Potter and L. E. Mklchebs 

 (Abs. in I'hytojMitholoay, 7 (1911), Xo. 1. pp. IS, 74). — It having been reporteil 

 that the nodal buds of maize were particularly subject to smut, the authors 

 made an investigation of the matter. They report that conidia probably do not 

 infect the corn plant directly, but that the result is rather the development of 

 a virulent culture of the fungus in the leaf axil. A plant thus infected may 

 become a center for aerial distribution, or. when rain occurs, the conidia may be 

 washed down or spla.shed on other leaves. 



The formalin treatment for controlling oat smut, J. A. Krall (Proc. loica 

 Acad. iS'ct., 2S (1916), pp. 593-620). — Describing the loss annually caused by oat 

 smut in Iowa and reviewing briefly the history and literature of oat-smut con- 

 trol measures, the author reports on his own experiments with treatments. 

 Various fungicidal preparations were employed unsuccessfully as contrasted 

 with formalin. 1 pt. of which to 20 gal. of water controlled the smut without 

 materially decreasing the vitality of the seed. A bibliography is appended. 



Some new facts concerning wheat smut, F. D. Heau) (Proc. Wash. State 

 Orain droircts. Shippers and Millers Assoc, 10 (1916), pp. SS-45, figs. t). — 

 Stinking smut, one of three types of smut that attack wheat, is the only one 

 now serious in Washington. Recent studies have been noted in part (E. S. R., 

 34, p. 644). Two new features which stand out with special prominence are 

 the occurrence of partially sniuttt^l grains and a general and extensive wind 

 dissemination of the spores. These are discussed in connection with some of 

 the better-known facts. 



All or part of the heads of a stool may be smutted, and in a given head the 

 smutting may be total or partial, showing wide variation. There is also great 

 variation in the position and size of the smut mass in partially smutted grains. 

 These grains in seed wheat would rarely l>e removed in cleaning, nor would 

 the spores be killed by ordinary fungicidal treatment, and it is thought that 

 a certain number will grow, vitiating the results from seed treatment. Fields 

 may become infected by wind-blown spores. The spores of unbroken smut 

 balls are not reached by fungicides, and will retain vitality in the soil for a 

 year or more, though after liberation few remain alive for more than three 

 months in moist soil and none of the.se are able to survive the winter. The 

 records of spoi'e traps show that during the thra.shing period ami the few 

 weeks that follow there are probalily many smut showers, the summer-fallowed 

 fields becoming thickly strewn with spores borne by the wind. 



The prevention of wheat smut, H. M. Woolman (Proc. Wash. State Orain 

 Oroivers, Shippers, and .Millers Assoc, 10 (1916), pp. 45-49). — In continuation 

 of the above discussion, the author states that although it is practically im- 

 possible by any one process to clean a very smutty lot of seed perfectly, the 



