Grazer

Caterpillars

Ragged chewed leaf margins or holes, dark droppings (frass) on foliage below, and caterpillars matching foliage color hiding along stems.

Severity

Identification

Caterpillars chew large, irregular holes through leaves and can strip a plant of foliage quickly once they mature. Many species camouflage well against stems and leaf veins, so the dark, pellet-like frass they leave behind is often the first clue, along with sudden leaf loss overnight.

Life cycle & spread

Moths or butterflies lay eggs on host foliage; larvae hatch and feed voraciously through several growth stages before dropping to the soil to pupate. A single generation can strip a plant within a couple of weeks under warm conditions, and several generations often overlap through the growing season.

Organic treatment

Hand-pick caterpillars off in the early morning or evening when they are most active.
Apply Bacillus thuringiensis (Bt), a bacterial spray that targets caterpillars without harming other insects.
Check leaf undersides regularly for egg clusters and remove them before hatching.

Chemical treatment

Use a targeted insecticide labeled for caterpillars if hand-picking and Bt fall behind the infestation.

Prevention

Inspect new growth and leaf undersides weekly during the growing season.
Attract predatory wasps and birds, which help keep populations in check outdoors.
Remove garden debris where pupae can overwinter.

Commonly affects

Solanum — Tomato →