Identification tip: Adults and nymphs are oval,
somewhat flattened, about 1/4 of an inch long, with a wide
head and prominent bulging eyes.
Hyposoter exiguae wasp adult
Identification tip: The adult wasp is black with
lighter colored abdomen and legs, and 1/4 to 1/2 of an
inch long. The adult wasp lays its egg in the caterpillar.
Although Hyposoter exiguae parasitizes both beet
and yellowstriped armyworms, it is the most important parasite
of beet armyworm.
Identification tip: After hatching, the larva develops
within the caterpillar and the host caterpillar shrinks
and becomes hard and brittle; if you pull apart a parasitized
armyworm, a green larva will pop out.
Identification tip: Adults are small, 1/12 to 1/5 of
an inch long, oval, black or purplish with white markings,
and have a triangular head.
Identification tip: The bodies of virally infected caterpillars turn
into shapeless sacks of dark liquid and can often be spotted hanging from leaves.
A nuclear polyhedrosis virus often reduces populations of beet armyworm in
fall and winter.