How to Manage Pests
Identification: Natural Enemies Gallery
Scientific name: Hyposoter exiguae
DESCRIPTION Life Cycle
The adult wasp is black with lighter colored abdomen and legs, and is 0.25 to 0.50 inch (6-12 mm) long. The larva is a light, translucent green. Hyposoter exiguae undergoes complete metamorphosis. The adult wasp lays its egg in the caterpillar. After hatching, the larva develops within the caterpillar, and the host caterpillar shrinks and becomes hard and brittle. The parasite then spins a cocoon inside the larval skin, or the caterpillar skin splits and the parasite emerges and pupates outside the host. Parasite development time from oviposition until adult emergence is about 1 month.
Look for the white speckled Hyposoter cocoons on leaves in the field. To find a parasitized larva look for a pale-green parasite inside. This is done by pulling either end of the caterpillar and allowing the wasp larva to pop out.
Hyposoter exiguae is one of at least 27 Hyposoter spp. in the United States, which attack dozens of different caterpillars.