Western Conifer Seed Bug Facts & Info

Everything you need to know about western conifer seed bugs

Western confider seed bug adults are 3/4 inch long and brownish on top. The upper (dorsal) side of the abdomen is yellow or light orange with five transverse black patches. This orange and black pattern on the abdominal dorsum is revealed during flight. The flight pattern and loud buzz produced by this strong flying conifer pest resemble those of a bumble bee. Their overall appearance can get them mistaken for stink bugs.

Western conifer seed bug nymphs start out orange, and then become reddish brown after a few molts. The eggs, which are laid in chains on conifer needles, measure about 2 mm each in length. The western conifer seed bug produces a single generation each season. Adults emerge from overwintering sites in late May or early June and feed on one-year cones and inflorescences – which are the complete flower head of a plant including stems, stalks, bracts, and flowers.

Eggs laid on host conifers hatch in 10 days, and first instars feed on the needles and tender tissue of cone scales. Later, nymphs use their piercing-sucking mouthparts to feed on developing seeds. Nymphs in all five stages of development and new adults can be observed feeding on the same group of cones by mid-August, at which time the nymphs begin to reach adulthood. Adults feed on ripening seeds until early fall and then seek overwintering sites under pine bark, in dead and dry Douglas firs, in hawk and rodent nests, and unfortunately inside homes and businesses in Massachusetts, Connecticut, Vermont, Rhode Island, New York, and Maine.

How Did I Get Western Conifer Seed Bugs

Adults and nymphs feed on conifer seeds (think pine cones), so your chance of having them around your home or business is directly related to your landscaping. You may never see them on trees, but you will notice them when they gather to overwinter inside structures such as houses or when they’re active indoors during the winter. They are adept at finding entry through any gap in siding, eaves, and openings around doors and windows. Their noisy, bumbling flight inside your home make them pretty hard to miss.

Where Do Western Conifer Seed Bugs Live

The western conifer seed bug frequently congregates on the outside of buildings in late summer and early fall in the northeastern United States – including New England. The large numbers of this insect observed around windows and doors of houses suggests that these are important points of entry for them. While they are more of an outside pest since their food is there, they will come into your home or business as the weather gets colder.

What Problems Do Western Conifer Seed Bugs Cause

The western conifer seed bug has been expanding its range extending across the northern United States into Canada. Interstate commerce has been a factor in extending the insect’s range. The western conifer seed bug is a nuisance to people in homes, offices, and laboratories in particular. The western conifer seed bug’s consumption of Douglas-fir seeds and seeds of various other species of pine results in a substantial loss of seed crop. Thus, its direct economic impact is a reduction in the quality and viability of conifer seed crops.

Even though western conifer seed bugs don’t not bite or sting, they can cause concern among occupants of homes, offices, and laboratories when it comes indoors. Complaints from residents increase as the insect becomes more active and conspicuous on days in the fall and spring when the temperature is above freezing. In several areas in the northeastern United States, this insect has created great alarm when large numbers of adults suddenly invade houses looking for overwintering sites. There’s a site you don’t want to see.

How Do I Prevent Western Conifer Seed Bugs

Since the western conifer seed bug is a persistent nuisance, the best method of control is having a professional come in to perform exclusion work like replacing loosely fitting screens, windows, and doors, caulking gaps around door frames, window frames, and soffits, caulking cracks behind chimneys and underneath the wood fascia, and screening fireplace chimneys and attic and wall vents. Replacing damaged or old screens can get pricey so exclusion work can be a more economical.

If you find you already have western conifer seed bugs, using a vacuum to collect a large group is effective, but they will leave an odor inside the vacuum cleaner. Collecting them by hand in containers (knock them into soapy water) and disposing of them is a better option. Overwintering insects inside structures often die before spring leaving behind their bodies, which may attract and feed other incidental pests, such as carpet beetles and silverfish. So, make sure if you see some dead bugs, get rid of them.

Why Waltham for Western Conifer Seed Bug Control

We’re passionate about keeping western conifer seed bugs out of your home or business because we live and work here – it’s our neighborhood, too. With our 130 years of experience keeping homes and businesses in Massachusetts, Connecticut, New York, Maine, Vermont, New Hampshire, and Rhode Island safe from pests, Waltham has the experience you can trust.
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