1308 THE FRUIT INDUSTRY IN XEW YORK STATE 



that reaches the body of the insect, and therefore the aim must be 

 to spray so as to kill the nymphs before they have developed their 

 wings. This is accomplished by applying the spray to the under 

 side of the foliage, between July 10 and 15 of a normal season, 

 using a spray containing .02 per cent of nicotine (^ pint of 

 Black-Leaf 40 to 100 gallons of water or bordeaux mixture). 

 The application to the under side of the foliage is accomplished 

 either by means of trailing hose or by an automatic grape leaf- 

 hopper sprayer. (iSee Geneva Experiment Station Bulletin 

 Xo. 344 for description of machine). This will kill the majority 

 of the brood, although a few eggs may hatch later and a few of 

 the earlier appearing individuals may have developed wings. 

 Sprays applied either earlier or later- than the above dates will 

 not have the maximum efficiency. 



This method of control means that the vineyard having a 

 serious infestation will be at the mercy of the adults during the 

 spring and early summer, and considerable injury may result to 

 the foliage. Injury to the more permanent foliage can be largely 

 avoided by allowing the shoots which spring up around the base 

 of the vine to remain until just previous to the time of spraying 

 instead of removing them in June, as is usually done. The habit 

 of the adults of flitting to the ground at the least disturbance of 

 the foliage and their return to the lower foliage makes this recom- 

 mendation feasible. 



Clean Culture 



Cover crops which remain green during the winter are of 

 great benefit to vineyards, and fortunately these crops do not har- 

 bor grape leaf-hoppers. Weeds and many strong-stalked grasses, 

 which die in the fall and lodge, offer excellent hibernating places. 

 By avoiding such rubbish in the vineyard and by keeping grass 

 patches surrounding vineyards closely mowed, almost perfect pro- 

 tection can be secured against these insects. The burning of 

 leaves and rubbish in fence rows and waste places near infested 

 vineyards during the autumn or early winter is recommended, 

 thereby destroying all hibernating places. 



