How to Get Rid of Tobacco Budworms

Ensure tobacco budworm larvae are present before applying Bt. Bt is not a contact insecticide and must be ingested by the larvae to work. The youngest larvae are the most susceptible. Young larvae generally are yellowish-green with a brown head. Tiny, thorn-like spikes give their bodies a rough appearance and feel.

Buy a Bt product specifically for tobacco budworm. There are several strains of Bacillus thuringiensis, each one specific to certain kinds of Lepidoptera larvae. Bacillus thuringiensis var. kurstaki is the strain used most commonly for the control of caterpillars. Make sure the product you choose indicates it controls tobacco budworm. Most formulations come as a wettable powder.

Wear safety glasses, a long sleeve shirt, and gloves when applying any pesticide. Bt is a very safe pesticide to humans and the environment, but as with any powdered product, dust can get in the eyes. Also, as a general precaution, be careful not to breathe in any dust or spray.

Mix the wettable powder with water in the ratio stated on the product label in the sprayer. Shake until the powder is suspended completely. Add in a spreader sticker for hard-to-wet crops and shake again. Don't mix the Bt with other pesticides or water soluble fertilizers. Mix up only the amount that can be applied in a 12-hour period.

Apply the spray to the undersides of leaves first, then the upper sides, allowing the spray to trickle down into the axils of the leaves where hungry larvae will find it. In hot sunny weather, spray in the late afternoon to reduce damage to the bacteria from UV light. Late day spraying also increases the residual control as the larvae are busy eating all night. Good coverage is a must for good control. Bt remains active on the leaves for 3 to 10 days, depending on the weather and the amount of direct sun. Treated areas are safe to re-enter immediately after spraying.