DISEASES INJURIOUS TO FORAGE CROPS. 43 



DISEASES INJURIOUS TO FORAGE CROPS. 



All of the more important diseases of forage plants observed were 

 caused by various species of smuts. This class of parasitic fungi 

 injures more than one would suppose the development of native eco- 

 nomic plants. While this is true, so little is known of the life history 

 of these species that no-suggestion can be made regarding their control 

 further than to state that the spread of those species which attack hay 

 plants could probably be checked by careful mowing and the removal 

 of hay from affected fields before the grasses head out, The acreages 

 are so large and the returns from them so small, however, that it is 

 doubtful whether any method which would be successful would be 

 financially j ustiliable. 



Ustilago hypodites. — In portions of the Great Basin, as well as in the 

 Okanogan region in Washington, a very large amount of damage is 

 done by this smut. It attacks both giant rye grass and salt grass, 

 transforming the undeveloped portions of the plants within the upper 

 leaf sheaths into a black powdery mass. It was especially destructive 

 in the Quinn River and Alvord regions in Nevada and Oregon last 

 year, and again this year in Surprise Valley, California, and at Love- 

 lock, Nev., on both hosts. 



Ustilago scolochloa. — This smut attacks the valuable sprangle top 

 (Scolochloa festucacea). Its black, sooty spores break through the 

 epidermis on the upper side of the leaves, stunt the growth of all the 

 leaves, prevent the upper ones from opening, and entirely destroy the 

 seed. At the "sod house'' on the lower course of the Dunder and 

 Blitzen River some meadows, in which one-half to two-thirds of the 

 vegetation consisted of this grass, had fully one-half of the plants 

 smutted. 



Tilletia fusca. — The hosts of this smut, the slender fescues (Fcs- 

 titca octoflora and F. microstachya), are annual plants, depending- 

 entirely upon seed for their reproduction. The fungus in this case 

 transforms the seed into a black horn-like structure, filled w^ith a com- 

 pact black mass of spores, entirely destroying it in practically the 

 same manner as the bunt destroys the kernel of wheat. Nothing 1 short 

 of the excellent seed habits possessed by these grasses would enable 

 them to thrive at all, for there are many localities in eastern Wash- 

 ington where upward of three-fourths of the plants had all their seed 

 destroyed. Reference is especially made to the region about 25 miles 

 north of Prosser, where the above statement would be no exaowra- 

 tion. At the same time another species of smut ( Ustilago mulfordina) 

 did some injury also. 



Ustilago bromivora. — The seed production of the valuable short- 

 awned brome grass (Bromus ?narginatus), as well as that of the closely 

 related cheat, is very materially reduced by this smut. The injury to 



