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House Invaders

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The Insect House Invaders of Autumn

There are several different species of insects rarely seen during the growing season that become quite problematic in the fall. These are the home invaders. They are the insects that quietly and inconspicuously go about their business, outdoors, in the summer but who seek shelter as the weather cools to overwinter in a protected site. They neither bite nor sting but are a problem by their sheer numbers and rude behavior. The most prevalent of these invaders is the Asian Ladybird Beetle which is also known as the Multi- Colored Ladybird Beetle or more commonly as the ladybug. It is a dull orange color and has anywhere from zero to 19 black spots on its wing covers. They are very effective predators and feed on such landscape and garden pests as aphids, scales, and some adelgids.

However, in late summer into the early fall, they will congregate in large numbers, often in the thousands, and seek shelter. This often occurs on/in homes that are lighter in color or are on more exposed sites, but they are a problem elsewhere as well. They can exude a foul odor when brushed, swept, or crushed; therefore its important to collect them with a vacuum cleaner rather than sweeping them up. They may also exude an orange-colored liquid that can cause staining of fabrics.

The Western Conifer Seed Bug is another relative newcomer to the East and it also invades homes in the fall, usually in much lower numbers than the ladybugs. This hemipteran (true bug) is about 3/4 of an inch long, has gray and brown coloration and greatly resembles the squash vine bug. It's size and slow movements can be quite alarming to some but they are relatively harmless. However, when handled or crushed, they also exude a foul smelling odor.

The Birch Catkin Bug usually becomes noticed prior to all the other invaders listed here. Immatures of this lygaeid hemipteran often develop in the seed capsules of azalea, rhododendron and Japanese andromeda. They will congregate in large numbers on birch trees (especially white-barked birches) in August and September. From there, they may move to the sides of homes. These insects are rather small and may not actively seek to be in homes; often, they are brought in on clothing as people walk by them and they fly onto the person. These bugs can also exude a foul smelling odor when crushed.

The Boxelder Bug spends the summer using its piercing-sucking mouth to feed on seeds, especially those of the boxelder tree (Acer negundo). This 1/2 inch long, black hemipteran bug has orange markings and will congregate in large numbers on the sides of homes and seek entry. Their presence is often quite alarming and unwanted, which often leads the homeowner to finally remove the host female boxelder tree next to their homes.

Most homeowners quickly lose the unique feeling of curiosity that these insects usually impart and their emotions soon turn to dread and frustration. There are a few common sense approaches that homeowners can take as precautions against these unwanted house guests.

  • Inspect all doors, windows, and attic vents every summer for small openings in screening.
  • Caulk breaks around the trim and fill any crevices that may have opened due to wood shrinkage.

Once any of these problems are discovered, they should be remedied as soon as possible in order to keep these pests outdoors. Once they have found a way inside, these insects can be vacuumed up. Remove the vacuum bag and place it into a tightly sealed plastic bag and move it to an outdoor location. In the case of the ladybugs, the true gardener will vacuum up the offenders and store them in the vacuum bag in a cold garage or shed until spring arrives. They can then be released back into the environment to feed on the landscape and garden pests.

Written by: Robert Childs
Revised: 10/2011

Topics: 
Commercial Horticulture
Commercial Horticulture topics: 
Insects and Mites