Grape Leaffolder Caterpillar

The grape leaffolder, Desmia funeralis, is a moth in the family Crambidae whose caterpillar is best known for the distinctive rolled or folded leaf shelters it constructs on grapevines. Adults are small, dark moths with white wing markings, active mainly at dusk.

The caterpillar's habit of folding a leaf edge over and securing it with silk gives it protection from predators and weather while it feeds on the enclosed leaf tissue. This behavior is shared by a number of unrelated moth species collectively called 'leaffolders' or 'leaftiers,' each specializing on a different host plant.

Found on both cultivated and wild grapevines across much of the southern and central United States, the species is a recognized, if generally minor, pest of vineyards, with damage usually limited to foliage rather than the fruit itself.

• Caterpillar is slender and pale green, blending closely with grape leaf tissue
• Reaches about 2 cm (0.8 in) in length at maturity
• Found inside a distinctive rolled or folded section of a grape leaf, held closed with silk strands
• Feeding leaves behind irregular, skeletonized 'windowpane' patches on the leaf where the caterpillar has fed from within its shelter
• Adult moth is dark brown to black with bold white patches on the wings, quite different in appearance from the larva

Occurs on grapevines, both cultivated and wild, across the southern and central United States, particularly in warmer grape-growing regions. Larvae are active from spring through fall, with more than one generation typically overlapping through the growing season.

Newly hatched larvae begin by feeding on the leaf surface before rolling or folding a section of leaf and securing it with silk to create an enclosed feeding shelter. The caterpillar remains largely hidden within this rolled leaf as it feeds, only occasionally leaving to construct a new shelter as it outgrows the old one or exhausts the available leaf tissue. This concealed feeding strategy offers protection from many predators, though the caterpillars remain vulnerable to certain parasitic wasps that specialize in locating hidden larvae.

Adult moths lay eggs on grape leaves, and larvae hatch and begin constructing rolled leaf shelters soon after. They pass through several instars while feeding within successive leaf rolls, then pupate either within a final leaf shelter or in leaf litter near the base of the vine. Multiple generations occur per year in warmer parts of the range, with the species overwintering as a pupa.