What are occasional invaders?

Jul 22, 2022, 14:12 PM by Fred Speer

When most people think of a pest infestation, it’s likely they think of ants, cockroaches, or rodents. However, there are many other pests that don’t immediately come to mind. These so-called occasional invaders can quickly turn into a nuisance.

Occasional invaders are a group of arthropods that invade structures from time to time. These pests often find their way inside homes throughout the year when weather conditions become hostile to their survival – for example, the excessive heat and drought common during California summers. This group of pests includes boxelder bugs, centipedes, crickets, earwigs, ladybugs, millipedes, pillbugs, scorpions, silverfish, slugs, springtails, and stink bugs, to name a few.

They usually enter the home through exterior cracks or openings in search of the ample food, water, and harborage that homes offer. Once inside, occasional invaders can’t survive for long periods of time if water is not available, and are likely to die within a few weeks.

What time of year are occasional invaders most active?

Occasional invaders are active all year long, and they spend most of their time outdoors. However, you’ll tend to notice them more frequently inside during summer and fall because they are searching for a place to get out of the harsh weather conditions (e.g., heat) or overwinter.

Can occasional invaders cause problems?

Although occasional invaders may enter structures in large numbers, they are often nothing more than an annoying nuisance. However, there are a few specific pests that can cause non-health-related problems. Stink bugs are harmful to the agricultural industry because they destroy crops. Boxelder bugs and ladybugs may exude a defensive fluid when crushed that can stain curtains, drapes, clothing, and other fabrics. Silverfish infest paper – particularly wallpaper, books, and envelopes – so these materials could become damaged over time.

Five tips to prevent occasional invaders

Spotting a stink bug on the wall or a centipede crawling across the floor is common. While most of these pests do not pose a serious threat, it’s still important to take precautionary measures to prevent them from coming inside.

1. Seal openings: Occasional invader control starts outside by sealing cracks around windows, doors, siding, and utility pipes, and underneath wood fascia, with a good quality silicone-latex caulk. Damaged screens on doors and windows should also be repaired or replaced. Don’t forget to check for torn weatherstripping and loose mortar.

2. Reduce moisture: Reduce or if possible eliminate all moist harborage sites inside the home – specifically in basements, attics, garages, and crawlspaces – because most occasional invaders are attracted to moisture. Check for leaky water pipes under sinks, ensure that drains are not clogged, and look for signs of moldy wood. If there is any evidence of moisture buildup, install a dehumidifier.

3. Maintain landscaping: Another key to controlling occasional invaders is the removal of debris around the exterior of the home, such as mulch, leaves, grass clippings, stones, and boards, as some of these pests are often associated with vegetation. Frequently mow and edge the lawn, weed plant beds, and trim tree limbs to deny pests harborage or access routes to your home.

4. Change bright lighting: Some occasional invaders, such as stink bugs and weevils, are attracted to bright lights, so it’s recommended that you change outdoor lighting to yellow bulbs or sodium vapor lamps, both of which are less attractive to pests. Inside, windows should be shaded with blinds and curtains so that no significant light is visible from the outside.

5. Remove with a vacuum: If occasional invaders do enter your home, temporary but immediate relief can be achieved by using a shop-type vacuum to aid in their removal. However, if a vacuum is used to get rid of stink bugs, the bag must be thrown out to prevent the odor from permeating the area.

Got questions about occasional invaders? Call Clark.

It’s important to understand that an influx of occasional invaders can quickly turn into an infestation if no action is taken. If occasional invaders are showing up indoors in numbers you can’t easily handle, or you’re seeing increased pest activity around your home or yard, call or text (800) WE-NEED-YOU (936-3339) or email us at

Until next time, the pest management professionals at Clark Pest Control thank you for helping to keep unwanted pests out of your home.

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