GRAPE INSECTS 



419 



itself by a silken thread. The caterpillars become full-grown 

 in about a month from the time of hatching, and transform 

 within the folded leaf into a brownish pui)a about one half of 

 an inch in length. The moths emerge in a wiM'k or ten days, 

 and lay eggs for a second brood. 



There are two broods ; the moths of the first ai)])earing in 

 June or July, and the second in August or September. The 

 winter is passed in the pupa state in the folded leaves on the 

 ground. The first brood is comparatively small and its 

 work relatively inconspicuous ; the second brood, however, is 

 sometimes numerous 

 enough to defoliate 

 the vines more or less 

 completely, and thus 

 either prevents the 

 proper ripening of the 

 fruit or exposes it to 

 injury from sun-scald. 

 In a few instances 

 caterpillars of the 

 first brood have been 

 observed feeding in the blossom clusters which they had 

 webbed together after the manner of the grape-berry moth. 



In California the larva seems to have somewhat different 

 habits than in the East. It rolls rather than folds the leaf and 

 feeds on the free edge of the leaf inside the roll instead of eating 

 off the upper epidermis. 



Treatment. 



The grape leaf-folder can be controlled by spraying the leaves 

 with an arsenical poison at the time when the first-brood cater- 

 pillars are hatching, taking care to cover evenly the upper 

 surface of the leaves. In small vineyards it is often practicable 

 to go over the vines and crush by hand the larvae or pupae in 

 the folded leaves. 



Fig. 362. 



Male moth of the grape leaf- 

 folder (X 21). 



