Tip Top Bio-Control Technical Bulletin

Aphelinus abdominalis
Aphid Parasite

Target Pest:
A wide range of Aphids. Aphid parasite of choice for the potato aphid (Macrosiphum euphorbiae) and the glasshouse potato aphid (Aulacorthum solani).

Description:
Aphelinus abdominalis are parasitic wasps. Adults are about 2.5-3 mm in length with short legs, short antennae and a yellow abdomen. The other stages of development occur inside the host.

A female can lay up to 250 eggs in a 3 week cycle. The female wasp will lay an egg directly into the aphid body where it hatches and the larvae will consume the aphid's body from within. When the parasite larva is fully grown, the host hardens into a leathery black colored mummy. The aphid turns black 7 days after parasitism. The mummy then takes an additional 14 days to develop into an adult wasp. The adult wasp emerges through a jagged edged hole at the rear of the mummy. The first mummies should be seen in your crops in a minimum of 14 days after the first release.

Product information:
Minimum of 250 viable adults per unit. A food source is provided to ensure that emerged adults arrive in the best possible condition. Aphelinus tend to walk over crops rather than fly, so it remains on the crop and does not readily leave the greenhouse.

Release Rates:
Release parasitic wasps onto infested plants by opening the bottle and placing it at the base of the affected plant. Best results are obtained by making low rate preventative releases when there is a risk of aphids invading the crop. If larger outbreaks of aphids are found, larger release rates should be made immediately.

Curative light release: 80 wasps per 40 sq. ft. of canopy with two weekly introductions into infested areas.
Curative heavy release: 160 wasps per 40 sq. ft. of canopy with two weekly introductions into infested areas.

Strategic Considerations:
Proper identification of the aphid species is important. Monitoring the crop closely and early releases will help in overcoming the pest. Pesticides and even wetting agents and spreader-stickers may adversely affect A. abdominalis survival. Broad spectrum and systemic insecticides are toxic to these wasps.