1306 



THE FRUIT INDUSTRY ix XEW YORK STATE 



the vines vary with the season and the locality. In the Chautauqua 

 region it is seldom that they are present in numbers sufficient to 

 inflict damage over an extended area, pasc 

 records indicating that this occurs about 

 once in every eight or ten years. In the 

 other grape regions of the state they are 

 more abundant each season, considerable 

 injury occurring to the vineyards and dur- 

 ing shorter periods. In individual vine- 

 yards, especially those near favorable 

 hibernating places or in close proximity 

 to the spring food plants of this insect, 

 serious injury may result for a number 

 of seasons in succession. The spring food 

 plants most preferred are strawberry, rasp- 

 berry (both red and black), and blackberry. 



The insect obtains its food by piercing the epidermis on the 

 under side of the leaf and sucking the sap. Additional injury is 

 caused by the insertion of the eggs under- 

 neath the skin of the leaf. All such punc- 

 tures decrease the starch-producing area of 

 the vine, which results in decreased pro- 

 duction of wood and in a decided lowering 

 of the quality of the fruit. 



FIG. 446 NYMPH OF 



GRAPE LEAF-HOPPEB 

 ( Fifth instar ; enlarged ) 



Life History 



The eggs are deposited during the 

 month of June and early July. Those 

 first deposited hatch from June' 15 to 

 the end of the month, but the majority 

 hatch by about the tenth of July. The 

 young leaf-hoppers are known as nymphs 

 and resemble the adults in form, with the 

 exception of having no wings (Fig. 446). 



FIG. 447 ADULT GRAPE 



LEAF-HOPPER 



( Enlarged ) 



These nymphs reach the adult stage (Fig. 447) during August: 

 many of them mate and eggs are laid, from which a second brood 

 develops. Individuals of the second brood reach maturity about 



