Biocontrol Agents

All Aphidius species are parasitoids of aphids. Aphidius ervi is effective against larger aphid species, such as Potato aphid and Foxglove aphid, but is ineffective against Green Peach and Melon aphid.

Aphidius species are very small, non-stinging wasps with long, slender body and long antennae. Aphidius ervi are all black and are larger than the other Aphidius species.

Aphidius ervi

A single female Aphidius can lay over 300 eggs, mostly within the first week of adulthood. A female will lay an egg inside the body of an aphid. The egg hatches and begins to consume the aphid from the inside, eventually killing it. A dead, parasitized aphid is known as a “mummy”, and are tan-coloured with a papery-bronzed appearance. The fully developed parasitoid chews a hole in the outer casing of the mummy and emerges and begins searching for new aphids to parasitize. Development from egg to adult takes approximately 12 days at 25°C.

Aphid mummy

Aphidius species are very good at dispersing and searching for hosts, and are able to detect aphids even when they are at low densities. They are most effective if released when aphids are first detected in the greenhouse.

Packaging

• Aphidius species are sold as mummies in bottles or blister packs with buckwheat hulls or vermiculite as a carrier material.
• Refer to the Quality Assurance of Biocontrol Products to determine the quality of the Aphelinus at receipt at the greenhouse.
• While they can be stored at 8-10°C, cold storage for more than 1-2 days after receipt may decrease their quality

Distribution techniques

• Sprinkle mummies directly on leaves, or in a thin layer in a distribution box nested within the plant canopy
  Distribute in greenhouse within 1 day of receipt

Introduction rates

• Preventative: 0.05-0.25/m²
• Curative: 0.5-2/m²

Environmental considerations

• Aphidius ervi are not active in hot temperatures above 30°C or below 15°C

Monitoring

• Parasitized aphids, aka “mummies”, look like aphids that have a bronzed, light brown, papery skin
• Mummies should appear in your crop around 2 weeks after initial release
• In foxglove aphid it is normal to see fewer mummies due to their habit of dropping from the leaves after being parasitized.

Factors affecting

• Aphidius species are sensitive to many pesticides. Please consult the  Quick Reference Guide to Registered Pesticides made by OMAFRA for compatibility information of products registered in Canada. Koppert and Biobest also have pesticide compatibility information listed on their websites.