Western Conifer Seed Bug Makes an Appearance

What is it?

It's big. It's brown. It's a bug. Most likely, it has invaded your home or office in search of a warm, cozy place to spend the winter. It's the Western Conifer Seed Bug, and it's harmless: It doesn't bite, sting, or damage your house. However, if you handle the bug, it will give off a pungent odor which some describe as a smelling rather nutty. If you squish them, they leak a Windex-blue fluid. (Perhaps they're an aristocratic bunch of blue-blooded bugs?)

Where does it come from?

The Western Conifer Seed Bug comes from, well, the West. Like some sort of reverse pioneers, they've been slowing making their way east.

First described in California around the turn of the century, the bugs reached Iowa in the 1950s. Twenty years later, they were nicely settled in Wisconsin and Illinois. By the 1980s there were confirmed sighting in Minnesota, southeastern Michigan, and southwestern Ontario.

The first documented collection of the bugs in New York State was from an Erie County home in January 1990. By February of 1992, Dr. Wayne Gall of the Buffalo Museum of Science had received specimens from nine counties of western and central New York. By 1994, the bugs reached from Long Island and the lower Hudson Valley region.

What does it look like?

The Western Conifer Seed Bug belongs to the family Coreidae, commonly called leaffooted bugs, and like many members of this family, it has a flattened, leaflike expansion on the hind legs. The adult is about 3/4 inch 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 (yes, it can fly), it lifts its wings to reveal bright yellowish orange areas on its back.

What does it Eat?

The Western Conifer Seed Bug dines on, well, conifer seeds! It pierces the scales of conifer seeds and sucks out the seed pulp. Host plants includes white pine, red pine, Scots pine, Austrian pine, mugo pine, white spruce, Douglas fir and hemlock. If you have any of these trees near your home or office, that explains why the bug has invited itself inside to spend the winter. In spring, the bug will move outdoors to feed on the developing seeds and early flowers of the conifer trees.

Female bugs 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.

What can I do?

If these bugs are a problem in your area, screen your 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 bug. Leptoglossus occidentalis (Heteroptera:Coreidae),