In contrast to predators who eat their prey, small parasitic wasps
(called parasitoids) lay eggs inside or on the body of their host.
Typically only one egg is deposited in one host, but parasitoids can
lay hundreds of eggs a day. Parasitoid larvae (immatures) develop by
feeding and killing the host.
Because most parasitoids are small and spend much of their lives hidden
within their hosts, many people are unaware of how common and important
they are in the control of insect pests.
Avoid broad-spectrum insecticides that can kill parasitic wasps and other
natural enemies are in your landscape.
species of tiny wasps lay their eggs in pests
like aphids or caterpillars; their hatching larvae
consume the pest and kill it.
Life cycle of an aphid parasite
A. An adult parasite lays an egg inside a live aphid. B.
The egg hatches into a parasite larva that grows as it feeds on the
aphid's insides. C. After killing the aphid, the parasite pupates. D. An
adult wasp emerges from the dead aphid, then flies off to find and
parasitize other aphids.
A parasitic wasp, Trioxys pallidus, parasitizing
a walnut aphid
Mummified aphids are the result of being parasitized
by a parasitic wasp. The holes in the mummies show where the fully-grown
wasp emerged. Mummies may be bronze or black depending on parasite
Visit the Natural Enemies
Gallery and the Biological
Control Pest Note for more information on parasites.