Agriculture: Walnut Pest Management Guidelines

Natural Enemies of Aphids

Natural enemies play an important role in the natural control of the dusky-veined aphid. They also feed on walnut aphid, but the introduced parasite Trioxys pallidus keeps the population of that aphid so low that predators seldom build up to large numbers on walnut aphid populations. Use the photos below to identify natural enemies or evidence of them. Names link to more information on identification and management.

Click on photos to enlarge

Ashy gray ladybeetle larva
Ashy gray ladybeetle (larva)
Identification tip: Ashy gray ladybeetle larva resembles a tiny alligator and has yellowish spots on its thorax and abdomen.

Ashy gray ladybeetle adult
Ashy gray ladybeetle (adult)
Identification tip: Thorax and wing covers are gray to pale yellowish with black spots (a black form with 2 large red spots also occurs).

Brown lacewing larva
Brown lacewing (larva)
Identification tip: The larva resembles a tiny alligator, flattened, tapered at the tail, and has distinct legs and prominent mandibles with which it attacks its prey.

Convergent lady beetle larva
Convergent lady beetle (larva)
Identification tip: Larva is elongate with long legs, and resemble a tiny alligator.


Convergent ladybeetle (adult)
Identification tip: Adults have orange to red forewings and up to 13 black spots. Many individuals have fewer margin and two converging white lines.


Green lacewing (larva)
Identification tip: Larva is pale with dark markings, looks like a tiny alligators.

Syrphid flies larva
Syrphid flies (larva)
Identification tip: The larva is legless and maggot shaped. It can be distinguished from caterpillar larva by its tapered head, lack of legs, and opaque skin.

Trioxys pallidus
Trioxys pallidus (walnut aphid parasite)
Identification tip: The female wasp lays an egg inside an aphid nymph.

Aphid mummy
Aphid mummy
Identification tip: Look for exit hole in aphid mummy where adult parasite (Trioxys pallidus) emerged.

Text Updated: 12/07
Feedback