KORSCHELTELLUS GRACILIS (GROTE): A PEST OF RED SPRUCE AND BALSAM FIR ROOTS (LEPIDOPTERA: HEPIALIDAE)

Abstract

AbstractKorscheltellus gracilis (Grote) is a pest of red spruce and balsam fir roots in the forests of the northeastern United States and southeastern Canada. The larvae feed below ground on woody and non-woody plant tissues for 2 years before maturing. It was found at 18 localities across New England and Nova Scotia during the summers of 1987 and 1988. On Whiteface Mt., New York, and Mt. Moosilauke, New Hampshire, larvae were absent to uncommon at low (500 m) and high (1300 m) altitudes, but common to abundant in red spruce – balsam fir associations at 700, 900, and 1100 m. During September 1987, larval populations were estimated at 56 000 and 312 000 per hectare in soils at 900 m on Whiteface and Moosilauke, respectively. Dense populations occurred locally, e.g. 27 larvae were recovered from a single 0.25-m2 soil pit at 900 m on Moosilauke. By June 1988, larval numbers on Whiteface and Moosilauke had declined by 51% and 72%, respectively. Seedlings and mature trees of both spruce and fir were damaged by larval feeding on bark and cambium. Seedlings were girdled; mature trees had wounds paralleling the root axes.