INSECTS INJURIOUS TO POTATOES AND TOMATOES 301 



fested places look very much like the ordinary scab produced 

 by the scab fungus and may be readily mistaken for it. Such 

 injury was quite general and serious in West Virginia in 1891 and 

 1892. Dr. Hopkins found that " they breed in and are especially 

 common in barnyard-manure/' that " excessive moisture in the 

 soil has been observed to be the most favorable condition for 

 their development/' and that " soaking the seed-potatoes in a 

 solution of corrosive sublimate previous to planting " will kill all 

 the eggs and young larva?, as it will also destroy the spores of 

 the potato-scab fungus. 



Professor H. Garman * has also recorded the injuries of several 

 species of millipedes, or " thousand-legged worms," Cambala 



FIG. 219. Potato scab-gnat (Epidapus scabei Hopk.): a, fly; i, larva; g, 

 egg; h, egg mass much enlarged. (After Hopkins.) 



annulata and Parajulus impressus, as causing a scab by gnawing 

 into the surface of the tubers. Though both of these observations 

 arc unquestionably true, such injury has not occurred in other 

 parts of the country, and it is improbable that any large portion 

 of potato-scab is due to these insects. Potato-scab is a fungous 

 disease, which, as already noted, may be destroyed by soaking 

 the seed-potatoes in a solution of corrosive sublimate. 



Blister-beetles f 



Long before we had made the acquaintance of the Colorado 

 potato-beetle, several species of blister-beetles frequently brought 



*H. Garman, Bulletin 61, Ky. Agr. Exp. Sta., p. 18. 

 f Family Meloidoe. 



