162 PESTS OF GARDEN AND FIELD CROPS 



The Hop Flea-beetle {Psylliodes pwidulata Melsh.) 



Leaves of hops, sugar beets, and some other plants are attacked by 

 very small, active beetles, which feed at first on the tender shoots and 

 buds and later eat holes in the leaves. The adult is about one tenth 

 of an inch long, shining black, its upper surface marked with many 

 minute pits in regular rows. 



The larva is slender, wliitish, and lives in the ground. There are 

 two generations in the hop regions of the 

 north Pacific coast. The insect hibernates 

 ^gflB^^ as an adult. 



^^k^^^H^BjP On sugar beets control is not easy. Bor- 



'^ deaux acts as a fairly effective repellent. A 



fair proportion of beetles may be poisoned by 

 applying arsenicals. 



Fig. 173. — The Hop Flea- Where the beetles appear suddenly in de- 

 beetle. Enlarged and j. x- i xi • i 



, 1 . r» • • 1 structive swarms on hops, their numbers may 



natural size. Original. . , 



be reduced materially by brusliing them from 

 the vines and catching them on sticky shields made by stretching cloth 

 over light frames and coating the surface with tar. Banding the 

 vines and poles with tanglefoot before the adults first appear will 

 largely protect the vines, since the adults seem to follow the habit of 

 crawling up the vines instead of flying. 



The Alfalfa Leaf- we evil {Phytonomus posticus Fab.) 



Alfalfa throughout the Western states is seriously threatened by this 

 pest, which is native to Europe and Asia and has accidentally been 

 introduced into this country. 



The plants are injured both by the adult weevils and by their young 

 or grubs. Depredations begin in early spring, when the beetles come 

 out from their winter quarters and puncture the young stems of alfalfa 

 to make places for depositing their eggs. Shortly the grubs hatch 

 and begin feeding on the tender leaves and the crown of the plant. 

 Transformation to the adult stage begins in June, and later the beetles 



