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The western conifer seed bug, Leptoglossus occidentalis (Heteroptera: Coreidae), is becoming a nuisance pest to some New York residents. The bug has the habit of entering buildings at the onset of cold weather in the late summer or early fall as it seeks a protected site to spend the winter. These bugs do not bite or sting, nor do they cause damage to the home. They will, however, give off a pungent odor if you handle them, which is part of the insect's defensive strategy. They also may make a buzzing sound when flying. |
Description
The western conifer seed bug belongs to the family Coreidae, commonly called
leaf-footed bugs, and like many members of this family, it has a flattened,
leaf-like expansion on the hind legs. The adult is about 3/4 inch (16-20 mm)
in length and is dull brownish. There is a faint white zigzag stripe across
the midpoint of its upper surface. When the insect takes flight, it lifts the
wings to reveal bright yellowish orange areas on its back.
The leaf-footed bugs use piercing sucking mouthparts to pierce the scales of conifer seeds and suck out the seed pulp. The list of host plants includes white pine, red pine, Scotch pine, Austrian pine, mugo pine, white spruce, Douglas fir and hemlock. Often these trees are planted or are growing near homes, and if that is the case, the bugs may seek the nearby buildings as an overwintering site.
History
The range of the western conifer seed bug has been expanding. In 1992 we
began to get reports from western New York State about these rather large insects
in homes. The first documented collection of this species in New York State
was from an Orchard Park (Erie County) home in January 1990. By February of
1992 Dr. Wayne Gall of the Buffalo Museum of Science had received specimens
from 9 counties of western and central New York. By 1994 we were seeing samples
from Long Island and the lower Hudson Valley region. It is now found throughout
the state.
This species was first described in 1910 from California, and was reported in Iowa in 1956. By the 1970's it was established in Wisconsin and Illinois, and by the mid-1980's was found in Minnesota, southeastern Michigan and southwestern Ontario.
Life
Cycle
In spring these bugs move out of doors to coniferous trees nearby. The bugs
feed on the developing seeds and early flowers of different species of conifers.
Females are reported to lay rows of eggs on needles of the host trees, which
hatch in about 10 days. Young nymphs then begin to feed on tender cone scales
and sometimes the needles. The nymphs are orange and brown, becoming reddish-brown
to brown as they develop. Nymphs pass through five stages and reach adulthood
by late August. Adults feed on ripening seed until they seek overwintering quarters.
Management
If these bugs are a problem in your area, be sure to screen attic or wall
vents, chimneys and fireplaces to mechanically block their points of entry.
Eliminate or caulk gaps around door and window frames and soffits, and tighten
up loose fitting screens, windows or doors. There are no pesticides specifically
registered for control of this leaf-footed bug.
If you already have a few western conifer seed bugs inside the home, you can remove them by hand. Although the bugs are not known to be harmful, they do give off a distasteful odor, which persists for some time. Use tissue paper or wear rubber gloves to pick them up, or a plastic jar with lid to capture them, and place them back out of doors or dispose of them.
References: McPherson, J. E., R. J. Packauskas, S. J. Taylor and M. F. O'Brien. 1990. Eastern Range Extension of Leptoglossus occidentalis with a key to Leptoglossus species of America North of Mexico (Heteroptera: Coreidae) Great Lakes Entomol. Vol. 23: 99-104
Koerber, T. W. 1963. Leptoglossus occidentalis (Hemiptera, Coreidae), a Newly Discovered Pest of Coniferous Seed. Ann. Entomol. Soc. Am V. 56: 229-234.
Wheeler, A. G. Jr. 1992. Leptoglossus occidentalis, A New Conifer Pest and Household Nuisance in Pennsylvania. Reg. Hort. V. 18: 29-30
4/95, Prepared by: Carolyn
Klass
Sr. Extension Associate
Department of Entomology
Cornell University
9/03, Reviewed by: Carolyn Klass
10/2003
