Tip Top Bio-Control Technical Bulletin

Cotesia marginiventris
Cabbage Looper Parasite

Target Pests:
Cotesia marginiventris is a parasitic wasp that lays its eggs in the caterpillar's early stages. Cotesia attacks a wide range of species, including the cabbage moth (Mamestra brassicae), beet army worm (Spodoptera exigua) and cabbage looper (Trichoplusia ni).

Description:
Females lay 25-35 eggs over a 2-6 day lifespan. When the eggs hatch, the wasp larvae feed inside the caterpillar, eventually killing it when the larvae exit to spin cocoons and pupate. Cotesia populations have more males than females with a ratio of 4:1.

Product information:
Cotesia is shipped 100 per tray and would be compatible with Trichogramma which parasitizes caterpillar eggs.

Release Rates:
Good control of cabbage loopers in greenhouse peppers if established with release rates of 4000 wasps/ha - 1600 wasps/acre, which would be about 1000 females/ha - 400/acre.

Greenhouse cucumber: 1-2 releases of 2500 wasps/ha - 1000 wasps/acre.
Greenhouse pepper & tomato: 1-2 releases of 7500 wasps/ha - 3000 wasps/acre.

Lifespan:
Cotesia marginiventris has a 2-6 day lifespan.

Strategic Considerations:
Monitoring is difficult because parasitized caterpillars are difficult to find, often dropping to the lower part of plants when attacked.