Symptoms
Large irregular holes eaten from leaves, often leaving only mid-ribs. Dark green droppings on soil and lower leaves. Plants rapidly defoliated. Large green caterpillars with white diagonal stripes and a horn visible.
Prevention
Inspect undersides of leaves regularly for egg masses and young caterpillars. Encourage parasitic wasps (Cotesia congregatus). Till soil after harvest to kill pupae.
Treatment
Organic
Hand-pick caterpillars. Apply Bacillus thuringiensis (Bt var. kurstaki) when caterpillars are small. Spray spinosad. Leave caterpillars with parasitoid cocoons (white rice-grain cocoons) undisturbed.
Chemical (last resort)
Apply carbaryl or permethrin as last resort when populations are high. Target young instars. Observe PHI strictly for edible crops.
Affects 1 crop
Sources
MARDI Vegetable Pest Guide; University of Florida IFAS