THE HOP FLEA-BEETLE. 



77 



brown freckles as the leaf grows and expands, the skin at this point 

 in time becoming torn and frequently showing holes. When the 

 beetle occurs in moderate numbers the leaves (fig. 14) become riddled, 

 as by fine shot, the punctures being most obvious after the plants have 

 made some growth. In its attack on hops it frequently causes the 

 leaves to look like a mass of network or more or less completely 

 strips the vines of leaves, as shown in figures 15 and 16. As is the 

 case with flea-beetles in general, this species does most harm to young 

 plants. AVhen the beetles occur in considerable numbers they are 

 capable of doing great damage in a comparativel}' short time, com- 

 pletely devouring 

 the young and 

 tender leaves as 

 fast as they come 

 up. 



Injurj^ is most 

 n o t i c e a bl e on 

 hops, sugar beet, 

 rhubarb, and some 

 other vegetables. 



The beetle is a 

 general feeder, the 

 list of its food 

 plants including, 

 among vegetables, 

 rhubarb, beet, cu- 

 cumber, turnip, 

 radish, cabbage, 

 mustard, and po- 

 tato. It feeds also 

 on hops, red and 

 white clover, nettle, dock (Rumex), lamb's-quarters (Chenopodium), 

 pigweed and tumbleweed {Amaranthus retrofexus and A, gnecians), 

 hedge mustard, and common wild-growing black mustard. The prob- 

 abilities are that, as all of these plants are afl'ected by the adult beetles, 

 a considerable proportion of them serves as food for the larva?. On 

 this head Mr. Quayle has written that the eggs, larva*, and pupa* 

 were taken at a depth of from three to six inches from the surface 

 of the ground in hop fields and that the larva? apparently feed on the 

 roots of hop as well as those of other plants growing in the yards. 

 Since it is well known that the beetles occur in other regions where 

 hops do not grow there must be other larval food plants. It would 

 be interesting, and is important, to ascertain exactly what plant, or 

 plants, is the favorite with the larva*. 



Fig. 14. — Hop loaves, showing work of flea-beetle. (Original.) 



