DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



the vines, although little foliage may have fallen from the vines by 

 that time. During the entire month of October a general dispersion 

 of the adults is in progress throughout the infested area. This disper- 

 sion is apparently quite aimless, the individuals settling down and 

 collecting wherever sufficient shelter in the form of fallen leaves, sod 

 lands, hedges, woodlots, and swales is adjacent to the vineyards. 

 Large numbers of them probably never leave the vineyards, passing 

 the winter under the }3rotection afforded by fallen leaves, clumps of 

 grass, weeds, and cover crops. After leaving the grapevines they 



feed to some ex- 

 tent upon the still 

 green grass, weeds, 

 and cover crops, 

 and become more 

 or less active when 

 disturbed 

 the warmer 

 of winter. 



during 

 days 



SPRING EMERGENCE 

 OF ADULTS. 



Early in May, 

 as the days be- 

 come warmer and 

 plants commence 

 to throw out new 

 growth, the adults 

 leave their winter 

 protection and 

 feed somewhat in- 

 discriminately 

 upon the new 

 growth of almost 

 an y plant with 

 which they come in contact, showing some preference, however, for 

 the foliage of bush fruits such as wild blackberries, cultivated rasp- 

 berries, and strawberries. This promiscuous feeding terminates with 

 the unfolding of the leaves of the grapevine and there is a general 

 migration of the insect back to the foliage of the grapevine, this being 

 the only plant upon which this particular species of leafhopper is 

 known to reproduce. 



The adult " hoppers " first attack the foliage or sprouts springing 

 from the base of the vine or from canes near the lower wire of the 

 trellis. When the adult insects are very numerous, sufficient injury 



Fig. 4. — Grape leaf in early stages of attack by the grape leaf- 

 hopper, showing the characteristic mottling of the upper sur- 

 face. (Original.) 



