Aphid Lysiphlebus Parasitoid / Home and Landscape / UC Statewide IPM Program (UC IPM)

Hosts or Prey

Aphids in the subfamily Aphidiinae

Identification

The most obvious evidence that L. testaceipes or its Aphidiidae relatives are present is the brown, gold, or tan, crusty, puffy (mummified) bodies of aphids on leaves and green shoots. When parasitized by a family Aphelinidae wasp the mummified aphids turn black.

Some mummies may have a round emergence hole of an adult parasitic wasp. The bodies of unparasitized aphids are soft and have no holes visible to the naked eye and they are the color(s) characteristic of the species. However, because the parasitized aphid's appearance does not change until about a week after the parasitoid egg is laid, the percentage of parasitized aphids can be greater than the percentage of mummified aphids.

The L. testaceipes adult is a slender wasp about 1/12 inch (2 mm) long. When aphids are abundant Lysiphlebus adults or their relatives can commonly be found walking among the colonies and inserting their ovipositor into aphid bodies. The adult wasp has long black antennae, a black head and thorax, and black and dark green abdomen and legs. Its pale eggs, maggotlike larvae, and oblong pupae occur hidden inside of parasitized aphids.

Life Cycle

Lysiphlebus develops through 4 life stages: egg, larva, pupa, and adult. The female wasp lays an egg inside aphids. The egg hatches in about 2 or 3 days and the larva develops through 3 increasingly larger instars as it feeds inside the aphid.

About 1 week after the mature wasp larva (prepupa) kills the aphid, it chews a hole in the bottom of the aphid's body, glues the body to the plant surface, and causes the host skin to turn brownish, crusty, and puffy. The parasitoid then pupates and within 4 or 5 days matures into an adult. The adult wasp chews a round hole in the top of the abdomen of the mummy and emerges. Adult parasitoids then seek mates and hosts that the female wasp parasitizes.

Lysiphlebus testaceipes overwinters as a prepupa or pupa inside parasitized aphids. Where winters are mild the parasitoid can be active throughout the year if aphids are present. Development from an egg to a reproductive adult takes about 14 days when temperatures average 70°F. Lysiphlebus testaceipes has multiple generations per year.

Habitat

Lysiphlebus testaceipes occurs throughout the United States and in all continents except Antarctica. It can be found in field, tree, and vine crops, gardens, landscapes, and wildlands where any of its numerous host aphids occur. In many situations it is the most abundant species of aphid parasitoid.

To improve biological control

Control ants because they attack natural enemies of aphids and other pests.
Grow flowering insectary plants to provide nectar to nourish adult parasitoids.
Reduce dustiness that disrupts the activities of natural enemies (e.g., periodically hose off small plants or irrigate overhead).
Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.

For more information see Protecting Natural Enemies and Pollinators and the table of relative toxicities of insecticides and miticides to natural enemies and honey bees for specific crops.

Species

At least 10 species of Lysiphlebus occur in the United States and L. testaceipes is the most common of these. Lysiphlebus testaceipes preys on over 100 species of aphids. Hosts include bean aphid, black bean aphid, cotton (melon) aphid, cowpea aphid, green peach aphid, hawthorn or parsley aphid, potato aphid, soybean aphid, strawberry aphid, turnip aphid, and wheat aphid.