42 



THE MONTHLY BULLETIN. 



orchards or fields in wliieli tlie liopper breeds. All food plants should 

 be kept out of the nursery. Sticky shields and hopperdozers may be 

 used with good effect. 



Natural Enemies. — The most effective natural enemy is the small 

 dark bug (TripJdeps insidiosus Say), which preys upon the nymphs by 

 puncturing their bodies and extracting the contents. 



The larvffi of the green lacewings also prey upon the young hoppers. 



THE GRAPE LEAF-HOPPER. 



Typlilocyha comes Say. 

 (Fig. 36.) 



General Appearance.— The adult insects are very small scarcely 

 more tlian one eighth of an inch long. During the summer they 

 appear light yellow with the wing covers or elytra mottled with red. 



As the season advances the color becomes 

 darker until winter it is dark red — this 

 change is due to the increasing brightness of 

 the red markings, which are very faint dur- 

 ing the summer months. The young appear 

 very much like the adults, excepting that 

 their wings are not fully developed and there 

 are less of the red markings. 



Life History. — The eggs are bean-shaped 

 and so small as to be almost microscopic. 

 They are inserted .just beneath the epidermis 

 on the underside of the grape leaves and 

 hatch in from fifteen to twenty days. The 

 young nymphs begin at once to feed upon 

 the first appearing foliage by extracting the 

 juices from the leaves with the sharp beaks. 

 There are two broods a year — winter and 

 summer. The adults of the former hibernate 

 and begin feeding upon the first foliage in the spring. During May 

 they begin egg-laying, which gives rise to the summer brood. This 

 brood grows very rapidly and lays eggs within a few weeks, dying off 

 in the fall. Their eggs give rise to the coming winter brood. Thus 

 the destruction may begin in May and end only when all of the leaves 

 have fallen. 



Fig. 

 hopper 

 (After 



3 6. — The f 

 Much 

 Johnson.) 



:i'ape leaf- 

 enlarged. 



all of the 

 in the San 



vnie-growmg 



sections of the 

 Joaquin and Sacramento 



Distribution. — Throughout 

 State. Especially abundant 

 valleys. 



Food Plants. — The principal and practically the only food during 

 the summer months is the foliage of the grape, but during the winter 

 many other plants are attacked, such as grasses, clover, alfalfa, 

 mustard, ragweed and filaree. 



