Abundant caterpillars, stripped trees, and bug poop dropping into your backyard BBQ can create an unpleasant environment. There are things you can do, however, to minimize the inconvenience. See the list of web sites you can visit. Forest tent caterpillars prefer aspen and birch trees in the northern counties and basswood and oaks in the central and southern counties. Widespread outbreaks of FTC occur at intervals of 10 to 20 years and are two to three years in duration.
Populations collapse due to starvation, predation, and parasitism.
The timing of biological events varies from year to year because timing depends on weather and location. For example, events will occur near the earlier date when the spring is early, when May and June are hotter than average, or when the location is south of Mille Lacs Lake. In the forest, FTC defoliation usually does not affect tree health because FTC populations usually collapse before tree damage occurs. FTC can consume 60 percent of a tree's foliage for three years and the tree will show no ill effects. Even completely defoliated trees will develop a second set of leaves in early July without a loss in health.