University of Maryland Extension

August Indoor and Outdoor Insect Tips

closeup European hornet
European hornet. Photo: Jim Baker, North Carolina State University,

(More tips from HGIC)


  • You may notice the European hornet stripping the bark off shrubs (especially lilac) and trees. This stripping of the bark is usually minor and does no real harm to a shrub or tree. The European hornet is a large yellow and brown hornet (photo) that nests in cavities in trees, stumps, wood piles, sheds, etc. and feeds on insects. Unlike most other wasps and hornets this one is a night flyer.
  • Do not spray pesticides in your garden unless you’ve observed a particularly serious pest and the damage caused by the pest. Follow all label directions. Always select the shortest residual, least toxic insecticide to avoid killing beneficial insects.
  • Avoid mosquito and midge problems by turning over any pots, lids or saucers that might collect water and create a breeding site. Also, check clogged house gutters another favorite breeding place for mosquitoes and midges. Many people use corrugated drain pipe attached to downspouts to help move water away from their homes. The corrugations hold water and are a prime place for tiger mosquitoes to breed. To avoid the problem, use a smooth drain pipe or securely attach the corrugated drain pipe to the downspout and cover the open end with a piece of pantyhose secured with a rubber band. This will keep adult female mosquitoes and midges out of the drain pipe.
  • Try to ignore hornet, bee and wasp nests found outside, especially if they are located in a tree. These are beneficial creatures that will not sting unless disturbed or provoked. However, if a hornet or yellowjacket nest is a threatening nuisance such as under your deck or next to your door you can destroy it with labeled sprays at night. Do not spray during the day or all you will do is to make them really mad because they cannot get back into their nest. Contact a pest control professional if yellow jackets are nesting inside the walls or attic of your home. Read more about stinging and biting insects on our insect profiles pages.
  • Earwigs are unique-looking insects that are reddish-brown, about 3/4 inches long. with a pair of pincers at the end of the abdomen. They can be found inside and outside the home in moist areas and are most active in the evening. They are predators of insect pests, like aphids, but may also eat seedlings and chew holes in large plants. They are a nuisance pest, causing little damage. (PDF HG 4 Earwigs)


  • Populations of pantry pests (PDF HG 67 Pantry Pests), like Indian meal moths, cigarette beetles and carpet beetles can build up over the summer because most people do less baking and infested products go unnoticed until the fall and winter. In late summer these insects are often found around windows trying to get out of your home. No chemical controls are recommended. These pests can be swept up or vacuumed.
  • Ants - Many different types of ants are very active this month inside and outside the home. The largest is the carpenter ant, some are 1/2 inch long. Carpenter ants tend to nest in wood that has been previously damaged by wood rots or insects. You must locate the nest to control this pest. Try using bait stations to control minor infestations of indoor ants. Granular insecticides or bait stations labeled for outdoor use on ants are also available. 
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