CEREAL PESTS PARASITIC FUNGI 533 



H. teres, on culture media, grows radially from the point 

 of inoculation ; while H. sativum, on culture media, grows 

 in a rotary, counter clock-wise manner. The latter causes 

 better defined and darker lesions on the leaves of the 

 barley plant, and is now recognized as the cause of the 

 " spot blotch " disease to distinguish it from H. teres, 

 the cause of the " net blotch " disease. 



Mortensen recommended, as a partial method of con- 

 trol, the Jensen hot-water treatment at a temperature of 

 124J , following an immersion of 3 to 10 hours in cold 

 water. Stormer adopted the use of a solution of formalin 

 ro- per cent strength, and an immersion period of 15 

 minutes. Ravn, who made an exhaustive study of these 

 fungi in Denmark, found that plants of barley seeded 

 in the cool months of spring or autumn were much 

 more affected than those seeded when the average tem- 

 perature was higher, July and August seedlings being 

 almost free of the disease. Soaking the seed in hot 

 water or in a solution of potassium sulfid appeared to 

 greatly reduce the disease. Appel and Riehm (1911) 

 have found that certain fungicides used for preventing 

 smuts, such as hot water and the mercuric salt of 

 monochlorophenol, may be used to great advantage at 

 the same time for preventing or controlling stripe disease 

 and wheat scab. 



575. Cereal anthracnose (Colletotrichum cereale, Selby 

 and Manns). This disease, fully described by Selby and 

 Manns (1909), is found on wheat, rye, oats, emmer, red- 

 top, timothy, and other grasses. Though rather widely 

 distributed, and capable of doing considerable damage, 

 this fungus has not until recently been recognized in 

 this country. The injury is done in shriveling of the 

 grain. 



