Earwigs: Adult insects up to 1 inch long, characterized by pairs of forcep-like organs of defense at end of body. They scavenge at night, hiding under porches, rocks, compost, litter, etc. in daytime. Feed mostly on vegetation outdoors, but often invade and eat stored food indoors.

Crickets: Large insects (usually over 1/2 inch long) sometimes winged but mostly using powerful hind legs for hopping and jumping. Noted for the chirping “song” of adult males. They usually feed on vegetation outdoors but invade buildings during droughts and cold weather, often attracted by lights, and eat foodstuffs, paper and clothing.

Ground Beetles: Large, long-legged, mostly flightless insects, often black or metallic blue or green color. They actively chase insect prey and often enter homes through doorways.

Sowbugs and Pillbugs: These are not insects but crustaceans, related to crabs and lobsters, adapted to life on land. They have 7 pairs of legs and an oval body up to 3/4 inch long covered in 7 “armor plates”. They feed on decaying organic matter, especially under logs and other moist locations, but frequently invade damp basements.

Centipedes: Flattened, elongated creatures up to 6 inches long, with one pair of long legs on most segments, antennae, and powerful poison jaws. These fast-moving predators catch and kill insect prey in damp situations indoors and outdoors.

Millipedes: Tube-shaped bodies, 1 to 2 inches long, with two pairs of legs on most segments. Slow-moving creatures which mostly feed on decaying vegetation in damp areas outdoors, but sometimes invade homes, especially in the fall.

Scorpions: Eight-legged creatures, related to spiders, mostly 2 to 3 inches long, with a pair of large pincers at front and a stinging tail. Found under tree bark, rocks and logs, especially in South and Southwest but as far North as Canada, feeding on insects. They commonly enter homes where they can survive without feeding for months.

What Can You Do Against Perimeter Invaders?

Fully effective pest control measures require expert knowledge of each pest. While the details vary with each pest situation, the main focus will generally be on outdoor measures aimed at preventing pest buildup and pest entry. Pesticides can play an important role in the fight against perimeter invaders. However, many over-the-counter pesticides do not perform well when used on porous outdoor surfaces, such as soil, wood and concrete. Also, the performance of most pesticides will be adversely affected by outdoor conditions, especially rainfall and ultraviolet light. In addition, special pesticide formulations or application techniques may be necessary outdoors to achieve control without harming plants, wildlife or groundwater resources. For these reasons, the selection and use of pesticides against perimeter invaders is best left to professionals. However, here are 10 specific nonchemical measures you can carry out that will discourage perimeter invaders and complement measures taken by professional pest control operators.