458 INSECT PESTS OF FARM, GARDEN AND OHCHARD 



mostly emerged and infest the vineyards. These hibernating 

 hoppers feed and breed on the lower leaves, disappearing about 

 the time the first young become adult. After a few weeks the 

 females commence egg-laying, which continues for about two 

 months. The eggs are laid just beneath the surface of the leaf 

 in groups of from six to nine, or singly, and as they are but one- 

 thirty-fifth inch long and almost transparent, they are scarcely 

 visible save for the eyes of the embryonic nymphs. The eggs 

 hatch in nine to fourteen days. The young nymphs feed like the 

 adults, at first on the lower leaves, but soon spread to all parts 

 of the plant. In New York they become grown in thirty to 

 thirty-five days, and there is but one full generation a year, 

 with a partial second generation, most of the individuals of 

 which probably do not mature before frost. Feeding continues 

 until cool weather, when the adults enter hibernation. In Col- 

 orado, New Mexico and California and probably throughout the 

 South, there are two full generations a year. In California, 

 according to Quayle, the nymphs from eggs laid by the hibernat- 

 ing hoppers appear by the middle of May and the following 

 generation of nymphs about the middle of July. 



Control. Cleaning up all fallen leaves and trash in the vine- 

 yard during the winter, or plowing it under in the early spring, 

 will reduce the number of hibernating hoppers, and it has been 

 observed that they are much less numerous in vineyards where 

 clean culture is practiced. The burning over of adjacent mead- 

 ows, wood lots and fence rows will also be advisable where 

 practicable. 



In California, where the vines are not trellised, a hopper-cage, 

 which has been fully described by Quayle, I.e., is successfully 

 used for catching the hoppers before they commence to oviposit 

 in the spring. In the East this could not be used, but Professor 

 Slingerland has shown that the "hibernated hoppers may be caught 

 on sticky shields before they oviposit. 



However, it has been found that such methods of capturing 

 and destroying the adults are expensive and give at best only 

 partial relief from the trouble. It has been found a much better 

 practice to kill the nymphs. This is done very efficiently by 

 spraying them with " Black-leaf 40" at the rate of 1 to 1500, 

 applying the spray at the time the nymphs are present in the 



