Infestation Levels of Dogwood Borer (Lepidoptera: Sesiidae) Larvae on Dogwood Trees in Selected Habitats in Tennessee

Infestation levels of dogwood borer [Synanthedon scitula (Harris)] on flowering dogwood (Cornus florida L.) in commercial nursery, urban, and forest habitats in eastern and middle Tennessee were measured during 1987 and 1988. The highest average infestation level (ca. 60%) was found in the urban habitat, where mechanical injury, e.g., damage caused by lawn mowers or string trimmers, may have provided oviposition or larval entry sites. Dogwood borer larvae were found in all nursery blocks examined, with ca. 7% of the trees infested/block. Infested trees are not marketable; thus, economic losses averaged ca. $l,800/block (x̄ = 1,770 trees/block) of dogwoods. Infestation levels were lowest (ca. 1%) in the forest habitat, where dogwoods grow as a natural component of the forest understory.