19 



Bagging. — Fruit may also be well protected by bagging the clusters 

 soon after the grapes have set. as already mentioned in connection 

 with the grape berry moth. 



GRAPE LEAF-HOPPER. 



Throughout the United States and Canada, wherever the grape is 

 grown, this small leaf -hopper {TypMocyba comes Say) w411 almost 

 invariably be found in greater or less numbers infesting the lower sur- 

 face of the leaf, where it feeds and breeds, increasing in numbers as 

 the season progresses, until by late summer and fall the vines are 

 often literally swarming with it. Throughout its extended range the 

 insect may be quite destructive in some localities nearly every year, 

 and is likely to become so elsewhere at any time. The grape leaf- 

 hopper is an insidious pest, often not noticed by the vineyardist until 

 late summer and fall, when the yellow and brown-blotched leaves, 

 falling prematurely, attract attention, by which time the injury has 

 been done. The insects in feeding extract large quantities of liquid 

 food, sucking it out from the interior of the leaf by means of their 

 tube-like mouth-parts. When they are abundant this constitutes a 

 heavy drain on the vitality of the plant. The injury to and loss of 

 leaves prevents the proper assimilation of food by the vines; the 

 fruit may be materially reduced in quantity and will lack much in 

 flavor and sugar content. Although the yearly loss to grape growers 

 from the attack of this species is sufficient to place it among the first- 

 class pests of the vine, but little effort ordinarily is made to control 

 it, perhaps principally because no very practicable remedy has until 

 recently been proposed. In the literature of the species there are 

 many records of serious outbreaks of the pest here and there over the 

 country, and recently the insect has attracted more than usual atten- 

 tion on account of serious injury in the Chautauqua and Erie grape 

 belts, where it has been carefully studied by Professor Slingerland.'^ 



Description and Life History. 



The adult grape leaf-hopper is quite small, measuring not more 

 than one-eighth of an inch in length. It is very agile, moving with 

 almost equa^ facility in all directions, and flies out from the vines 

 often in swarms upon slight disturbance. The general appearance of 

 the insect is shown in figure 6, the back of the insect being marked 

 with yellow or red, the exact pattern and color varying much among 

 different individuals and according to season. There are numerous 

 varieties of the insect based on these variations, several varieties often 

 occurring together on the same vine, though more usually insects 

 showing one type of color pattern will be found to predominate. The 

 insect passes the winter in the adult condition in hibernation in trash 

 in and near vineyards, in the edges of neighboring woods, in grass 

 along gullies, in ditches, etc. Early in the spring the insects come from 

 winter fjuarters and attack almost any succulent vegetation at hand. 

 By the time the foliage of the grape appears they are out in large num- 

 bers and begin to infest the vineyards. These adult hoppers of the 



a Bui. 215, Cornell Agrl. Exp. Station (1904). 

 284 " ' 



