Original source for U.S.
release was Europe. First U.S. releases made in 1989. Said to be
established in Idaho, Montana, Oregon, and Washington. No work with this
agent is currently underway in Stevens County.
This agent has two generations
per year. That is, there are two cycles of "EGG/to LARVA/to
ADULT" per year. Larvae are inchworms. The inchworm is not light
sensitive like the Chrysolina larva and can feed during the daylight
hours, although it is primarily a night feeder. It may be hard to see when
it imitates a dead twig. A Female moth lays about 300 oval shaped pearl
white eggs in her lifetime.
The second generation inchworm (hatched mid-August & September)
overwinters in plant litter or in the soil. These overwintered inchworms
becomes active again sometime in spring and can be seen into July. The
adult moth can be seen in spring and summer.
The larva feeds on leaves and
The establishment of this agent
in Stevens County is unclear. New releases are said to work best at sites
which are sandy, well-drained, and somewhat rocky.
The inchworm tends to get
fungal infections at moist soil sites. The inchworm is known to be
attacked and killed by ants and wasps.