Caterpillars on leaves or buds
Outdoors and greenhouses; feeding damage appears overnight..
- Also called
- caterpillars
- worms on my plant
- green worm
- budworms
Likely causes, most likely first
Ranked for this sign on its own. Your stage, medium and readings change the order, so run the checker for your plant.
LikelyCaterpillars and budworms
Fix: Hand-pick; exclude moths with netting; use Bt (kurstaki or aizawai) while larvae are small, since it must be eaten and breaks down in sunlight in days. Remove bored buds: frass starts bud rot.
Recovery: No fresh frass or holes after 1 week.
How to confirm it
- Open the densest colas. In flower, gently spread the largest, densest colas at the base and look for brown, mushy or grey tissue around the stem, a single wilted sugar leaf that pulls out easily, frass or caterpillars. Check 5-10 colas per plant each week from mid-flower, more when RH is high. Bag any rot before removing it.
Look for
The caterpillar itself, frass and the damaged leaf or bud..
The full guide: Caterpillars on cannabis: species, degree-days and control
Guidance, not a guarantee. The checker weighs common causes against what you tell it; confirm with the tests before you treat, change one thing at a time and watch the new growth.