Natural Insecticides For Earworm

Bacillus Thuringiensis (BT) - This is a bacteria that comes in powder form to be used as either a dust or a foliar spray. It kills only leaf-eating caterpillars like the corn earworm. To use it as a dust, thoroughly cover all parts of the leaves, especially the undersides, making sure to replace it after it rains. To use BT as a foliar spray, spray BT in liquid form on the affected plants at 10 to 14 day intervals until the earworms are gone. Once the earworm has entered the ear of corn, you can inject BT solution into the top of the ear with a syringe. On corn and other infested plants, an effective strategy is to add light horticultural oil to the liquid Bt and spray corn every two weeks from the time it is knee-high through to when the ears are beginning to form.

Light Horticultural Oil - Light horticultural oil, having a viscosity of 60 to 70 controls corn earworm during the growing season. Spray a 2 to 3% solution of oil in water directly on the earworm. The oil works by suffocation. If you add Bt to this light oil spray you increase its effectiveness significantly (see above).

Pyrethrum - Pyrethrum, a botanical poison, paralyzes corn earworm on contact. So spray the undersides of the leaves as well as the tops, since the worm is usually on the underside and must be sprayed directly. Usually two applications, three to four days apart will control the problem.

Rotenone - Rotenone is both a stomach and a contact poison to corn earworm. Dust it or dilute it with water for spraying. A 5% concentration in water will kill earworms. It can be used up to 24 hours before harvest. However, while it is effective against many pests, rotenone also kills beneficial insects.

Control Earworm With Synthetic Insecticides

Pyrethroid Insecticides will control Corn Earworm