CEREAL PESTS PARASITIC FUNGI 531 



dinary observer. It has usually been described heretofore 

 under the name of its conidial stage (Fusarium culmorum, 

 Sacc.). The work of Selby and Manns (1909) indicated 

 the probable connection of this stage with the perithecial 

 stage (Gibberella saubinettii) , and showed by cultures that 

 the forms found on wheat, oats, barley, rye, emmer, 

 spelt, and clover are the same organism. In nature, the 



FIG. 166. Effect of artificial infection of oat seedlings with the scab 

 fungus: a, inoculated with spores from wheat grass; b, check, not 

 inoculated ; c, inoculated with spores from oats. 



scab is more common on wheat, but sometimes occurs to 

 a serious extent on oats. It shows chiefly on the spike or 

 panicle, and, when fruiting, becomes pinkish in color from 

 the color of the conidiospores en masse. 



Further studies of Selby and Manns show that the scab 

 fungus survives as an internal infection in scab-infested 

 kernels of wheat. On germination of these diseased 

 kernels, the resulting young plants of the new crop become 

 infected and many are killed before a month old. Con- 

 siderable loss was caused in this manner to the wheat 

 crop in Ohio in 1907. The flowering period is the time 



