Monterey® BT Biological Insecticide - 32oz - OMRI Listed®

Monterey® BT Biological Insecticide 32oz — OMRI Listed® | Bacillus thuringiensis | Caterpillar & Worm Control

Monterey BT is a biological insecticide based on Bacillus thuringiensis (Bt) — the most widely used microbial insecticide in organic production. When caterpillars and worms ingest Bt-treated plant tissue, the Bt proteins disrupt their midgut cells, causing cessation of feeding followed by death. Effective against worms and caterpillars on fruits, vegetables, ornamentals, and shade trees. OMRI Listed for organic gardening and labeled for use on edible plants up until the day of harvest.

Key Features & Benefits

• Bacillus thuringiensis — Microbial Insecticide: A naturally occurring soil bacterium that produces proteins toxic to caterpillar and worm species when ingested — with no toxic effect on non-target insects, birds, mammals, or beneficial arthropods.
• Targets Caterpillars & Worms Specifically: Bt is highly selective — it controls caterpillars and worm larvae (Lepidoptera) without harming beneficial insects including bees, predatory wasps, or ladybugs.
• Broad Crop Application: Labeled for use on fruits, vegetables, ornamentals, and shade trees — one of the widest use-site profiles of any biological insecticide.
• Day-of-Harvest Safe: Can be applied on edible plants right up until the day of harvest with no pre-harvest interval requirements.
• OMRI Listed® for Organic Use: Certified for use in certified organic gardening and production programs.
• 32oz — Concentrate.

Who Should Use This

Home gardeners, organic vegetable and fruit growers, nursery operators, and landscape managers dealing with caterpillar and worm pressure on edible and ornamental crops. Bt is the go-to biological insecticide for caterpillar control — effective, selective, OMRI Listed, and safe to apply right up to harvest day.

Frequently Asked Questions

What pests does Monterey BT control?

Monterey BT controls worms and caterpillars (Lepidoptera larvae) — including common garden caterpillars, armyworms, cabbage loopers, tomato hornworms, and other worm species. See the product label for the complete pest list.

Is BT safe for bees and beneficial insects?

Yes. Bacillus thuringiensis specifically targets caterpillar and worm larvae through gut toxicity — it has no toxic effect on bees, beneficial predatory insects, or other non-target organisms.

When should I apply Monterey BT for best results?

Apply when caterpillars are young and actively feeding. Bt must be ingested by the caterpillar to be effective — thorough coverage of plant tissue where larvae are feeding is important. Reapply after rain or irrigation washes away treated residue.