⚠ ModerateRapid, overnight foliage loss � the work of a well-camouflaged tomato hornworm caterpillar.
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Pests
Tomato Hornworms Defoliating Plants
Commonly affects: Solanum lycopersicum (Tomato)
Large sections of foliage disappear rapidly, sometimes overnight, along with dark green droppings on leaves below the feeding site. Large, well-camouflaged green caterpillars with a distinctive horn-like tail can be found on the plant once you look closely.
Potential Causes
- 1Tomato hornworm (Manduca quinquemaculata) caterpillars feeding voraciously on foliage and sometimes fruit
- 2Adult sphinx moths laying eggs on tomato foliage in late spring and summer
- 3Well-camouflaged caterpillars going unnoticed until damage is already extensive
Solution Steps
- 1Hand-pick hornworms off the plant and dispose of them � check both the tops and undersides of leaves carefully, since their camouflage is excellent.
- 2Look for caterpillars covered in small white cocoons � these are parasitic wasp cocoons, and the hornworm should be left alone to let the beneficial wasps complete their cycle.
- 3Apply Bacillus thuringiensis (Bt), an organic caterpillar-specific treatment, if the infestation is heavy.
- 4Till soil after harvest to disrupt overwintering pupae in the ground.
Prevention Tip
Check plants regularly for the tell-tale dark droppings on leaves, which reveal a hornworm's location well before the visual damage becomes severe.
