Erroneously considered to be larvae of gypsy moths, tent caterpillars emerge every several years in vast numbers and can severely defoliate trees. While healthy trees rarely die as a result of caterpillar action, the infestation is unsightly and damaging. Egg masses of tent caterpillars are easily seen in fall and winter, as black “bracelets” clasped around the outer twigs of trees; these should be broken off and crushed underfoot. The eastern tent caterpillars, which feed on dogwood, fruit trees and willows, spin tents where they congregate, and are easily killed by penetrating the tents with forceful jets of a solution containing Bacillus thuringensis or a commercial insecticide. Forest tent caterpillars, which do not actually make tents, are equally damaging to maple, ash, birch, tupelo and poplar; they have the habit of climbing up to feed and then dropping via threads back to the ground, and can be controlled very effectively by wrapping tree trunks in sticky “bug belts” that halt their progress.