Seasonal development
and life cycle—Grape leaffolder
Grape leaffolders have three generations a year (about April - May, June 15 - July 15, and August).
After overwintering as pupae, moths emerge in April or May and lay flat, elliptical eggs singly on either
the upper or lower surface of the leaf. Many are deposited against the leaf veins on the underside of
the leaf. After hatching, larvae feed between two webbed leaves for about 2 weeks. Then each pale green
larva rolls a leaf edge and feeds from the inside on the leaf edge. Larvae turn darker green as a result
of this leaf feeding. If disturbed, larvae wriggle vigorously and drop to the ground without a silken
thread. Mature larvae construct a separate leaf envelope on the edge of a leaf in which they pupate. |
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