THE RAISIN INDUSTRY. 99 



yellowish white, with a few red spots. When the insect approaches 

 maturity, it jumps, but the undeveloped insect or larva only crawls, 

 principally on the underside of the vine leaves, where their cast-off 

 skins can be seen in all stages and sizes. The eggs are laid in 

 the veins of the leaves. The glossy globules which are always seen 

 on leaves where the leaf-hopper is found are not the eggs, as has 

 been supposed by many, but is only the vomit which, when irri- 

 tated, the hopper throws out either as a defense, or because it 

 desires to rid itself of an unnecessary burden. The leaf-hopper 

 hatches at least two times, or possibly three times, during the sum- 

 mer. Many of the insects remain over during winter time. They 

 feed on almost anything, such as alfilerilla (Erodium)^ etc., but are 

 especially fond of the grapevines, and even in the early spring flock 

 onto the young vine shoots, leaving the less desirable weeds. In some 

 localities this insect is known variously as the white fly, the vine-hop- 

 per, or incorrectly as the thrips. 



Damages. The hopper punctures the leaves and causes them to dry 

 up and fall, thus exposing the grapes to the hot sun. The excrement 

 of the hoppers also covers the grapes largely, and spoils their appear- 

 ance and keeping quality, at least as table grapes. It is principally 

 the table grapes and wine grapes which are injured by this insect; the 

 former are made unfit for shipment, and the latter do not color well 

 when deprived of their leaves. If the grapevines are kept growing, 

 the grapes are less injured, and some growers even contend that the 

 hopper is advantageous, as it causes the leaves to fall and the grapes 

 to mature. 



Distribution. It is not known whether the leaf-hopper is a native 

 of California, and I hardly believe it is. It does not exist in Southern 

 California, but in Northern California and in the San Joaquin valley 

 it is common. In the grape districts of Southern California there is 

 found another variety of leaf-hopper almost twice the size and of a 

 brilliant green color, which only once appeared in such quantity as to 

 do any damage at all. Generally it is quite rare. The Erythroneura 

 comes, however, occurs in countless numbers, and often rises in clouds 

 when the vines are approached. Irl some years it is less common than 

 in others, and after having been plentiful for several years gradually 

 diminishes in quantity, but never disappears entirely. 



Remedies. Pasturing the vineyards with sheep as soon as the grapes 

 are picked is very beneficial. The sheep destroy both hoppers and 

 leaves, and the following season always finds the hoppers greatly 

 diminished in numbers. The sheep do no injury to low-pruned vines, 

 and in Fresno many vineyardists pasture their vines regularly every 

 year in October and November, or as soon as the grapes are picked 

 and the vineyards are made accessible. 



The gauze bell consists of a bell-shaped cover made of wire netting, 

 large enough to cover the vine. The inside of the bell is sprayed with 

 petroleum, and then turned over the vine. A shake is then given the 

 vine, when many leaf-hoppers will fly up and stick in the petroleum. 

 It will only pay to use this remedy on table grapes; for raisin grapes 

 it is too expensive. 



