In the Garden:
New England
October, 2012
Regional Report

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On a cool October day, box elder bugs are busy looking for a way inside to find shelter for the winter.

They're Here! Dealing with Fall Insect Home Invaders

Just a few minutes ago, my peripheral vision caught a dark shape whizzing by. Then an oval insect with a black back accented in red landed on the desktop in front of me. A box elder bug had come to call!

He was not paying a social call, however. At this time of the year, when we find ourselves thinking about making our homes snug and warm for the coming months of cold, we're not the only ones concerned about shelter. A number of insects frequently make their way inside our New England homes in fall as they search for a cozy spot to spend the winter. None of these home invaders bites or stings, nor do they feed on clothing, furnishings, or stored food, or attack a house structurally. But they can be a real nuisance when they appear inside in large numbers, and they can stain fabrics and give off a foul odor when crushed -- not the kind of behavior we want from our house guests!

Box Elder Bug
Have you noticed 1/2 inch long, narrowly oval, red-lined black bugs congregating on the outside of a building, especially on a southern or western exposure? These are box elder bugs looking for protected places in which to overwinter. While they feed on a variety of plants and are especially fond of box elder (Acer negundo) tree seed pods, they are primarily a nuisance pest as they make their way inside homes in fall and winter, where they can stain light-colored surfaces and produce an unpleasant odor when crushed. If you deal with large numbers of box elder bugs each fall, cutting down nearby female (seed producing) box elder trees may help.

Asian Ladybird Beetle
One of the most common home invaders is the Asian ladybird beetle. This dull-orange little beetle is only 1/3" long, and may have anywhere from 0 to 19 black spots on its back. While these beetles are considered "good guys" in the garden as they feed on pests such as aphids and scales, Asian ladybird beetles can become a nuisance in the fall when they congregate in large numbers to seek shelter. They are attracted to buildings with light colored siding and the sunny south and west sides of buildings, where they look for cracks and crevices to enter. They often find their way inside buildings, where they can give off a foul odor when crushed or swept up. They can also exude an orangey substance that stains fabrics.

Western Conifer Seed Bug
This true bug is relatively new to our region and you're not likely to find it in large numbers. But its fairly large size -- it's about 3/4 of an inch long -- long antennae, and long legs can make it a somewhat alarming find inside. True to their name, during the growing season these bugs feed on the developing seeds of conifers, but are not considered a serious pest. They have rectangular backs that come to a point at the lower end and are brown with lighter markings. Their back legs are distinctive, with a wide, flat lower segment. They, too, will emit an unpleasant odor when handled or crushed.

Cluster Flies
Years ago I lived in an old farmhouse with lots of cracks and crevices that allowed creatures from mice to insects easy access. One fall day one of my roommates went upstairs, then called down in a frantic voice to come up quick. I went up into one of the bedrooms and walked straight into a scene worthy of a horror movie. The entire ceiling was crawling -- and buzzing -- with hundreds of cluster flies. The only thing missing was the scary background music! We spent several hours raising canning jars up onto the ceiling; when the flies flew down into them, we clapped on lids before they could escape, and then we dumped them outside.

Cluster flies look like large, sluggish houseflies. They may appear inside over the course of the winter as winter warm spells rouse them from their slumbers inside house walls. In the natural environment, they are parasitic on earthworms.

Brown Marmorated Stink Bug
This is one of the newest invaders on the scene and has not yet made its way to the northern reaches of New England. Unlike the other insects described, this one is indeed a garden pest. An Asian interloper, it first appeared in Pennsylvania in 1998. Since then, these stink bugs have spread throughout the Mid-Atlantic states and are now making their way into our region. The shield-shaped brown bugs have alternating dark and light patches along their sides and on their antennae and are a serious threat to peaches, apples, corn, and other vegetable crops. In early fall, you may find them massing on the exteriors of buildings, especially those near wooded areas, looking for a winter home. Like the other home invaders I've profiled, they are harmless to humans, but can emit a foul odor when handled or crushed.

Prevention is the Best Cure
They best way to avoid problems indoors with all of these insects is to seal up any openings around doors, windows and vents or any cracks in siding with caulk, and make sure screens are intact, including those over attic vents. Remove window air conditioners as soon as they are no longer needed and cover ones left in place with fine mesh netting. You'll reap the biggest benefits if you have your house sealed up by early September, but it's still worth getting out the caulk gun if the weather permits.

They're Inside -- Now What?
For the insects that do make it inside, the vacuum cleaner is your best remedy. After sucking them up, remove the vacuum bag and place it inside a sealed plastic bag and dispose of it. But if you're only dealing with a few insects, an updated version of my canning jar capture method may be easiest. Take an empty 2-liter soda bottle, cut off the top third and invert it, neck down, inside the bottom section of bottle. Place this wide-mouth trap over the insect, which will fly or crawl down into the bottle but will have a hard time escaping back out through the narrow neck opening.

As I mentioned, Asian ladybird beetles are considered beneficial in the outdoor garden. After you vacuum them up, consider storing the sealed bag in a cold garage or shed for the winter and releasing the overwintered lady beetles back into the environment when spring returns. This way they can once again go about their helpful business of dining on pests.

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