Colonies tend to nest outdoors in heavy mulch, leaf piles or ground covers, and sometimes near building foundations, which can lead to higher chance of them entering homes. Most ants end up in homes in search of food and water, and when they find it they can share the location with their colony using trail pheromones. 

When ants find an interior source food and water it increases the chance they will nest within the building. The species most likely to do this are pharaoh ants, rock ants and carpenter ants.

• Remove sources of food and water and if ants have been foraging in a home
• Wash down counters or floors with some household cleaner to eliminate the odor trails the ants have established.
• Clean up food from common locations such as, counters, floors, pantries and trash baskets
• Close water leakage from sinks, pipes and hoses
• Use slow acting insecticide in baits so ants will carry it back to their colonies

Bed bugs can be accidentally carried on furniture, luggage and other materials so problems with bed bugs tend to be most severe in apartments, motels and other sites that see high amounts of human traffic.

If bed bugs are present you’ll want to get rid of them. If helps to have a bed bug action plan before bed bugs are present because bedbugs can be difficult and costly to eliminate. Bites may result in redness, itching and swelling. In fact, infestations can cause sleeplessness and nervousness in those who have been bitten and negative social publicity for organizations that have their facilities infested.

There are many controls available, consult with a professional entomologist on best control methods, such as: 

• Chemical treatments
• Inspecting and monitoring areas with upholstered furniture as well as donations, lost and found items and children’s belongings
• Remove clutter or store in sealable containers
• Dispose or heat-treat infested items

Depending on the species, nests can be found in a variety of places, but are most often seen on the eves of buildings, in trees and underground. Examples of bees and wasps found in Colorado are: honey bees, paper wasps and ground bees.

Danger varies between bee and wasp species, some of which pose a minimal risk, like bumblebees, and others can pose a serious risk, like bald faced hornets.

If the type of bee or wasp does pose a risk, options for mitigating risks include:

• Install tight-fitting screens in windows
• Nest removal using a bee veil, suit and gloves, or conducted by a professional
• Using insecticide
• Minimize nesting habitat by caving in old rodent burrows and sealing exterior cracks and crevices, holes in trees, wall voids, removal of grass clumps, etc.

Cockroaches tend to move during hot weather and/or during flooding. When they seek shelter or food they move indoors. Depending on the species, the location and temperature sought varies. Generally, they can be found in kitchens, boiler rooms, basements and near leaky pipes.

Some species of cockroach can carry disease pathogens and bring them into the home. For most species, they are an asthma trigger and can cause allergic reactions to humans.

• Monitor areas where cockroaches are commonly found by using sticky trap monitors
• Improve sanitation throughout the house especially areas where cockroaches can be commonly found
• Throw away trash consistently to remove moist food and shelter
• Keep food in pest proof containers

The European earwig is the only earwig found throughout most of Colorado. Earwigs are generally found hidden in dark, moist areas such as under pots, rocks or stacks of paper. Most earwig problems begin in July. 

Earwigs are a nuisance pest, meaning that they don’t really cause any problems other than being in the home.

• Clear all areas of debris and seal all cracks on doors, windows or damaged areas
• Earwigs can be trapped with with rolled newspapers with food bait or oil based baits
  

Small flies can reproduce by feeding on overripe fruit, fungi in the soil of houseplants, or in drains. Other flies can enter the home seeking shelter. Generally, flies can be found in garbage, near food waste, or around windows.

The flies found indoors are most often nuisance pests, although those that develop in manure, carrion, and garbage may be contaminated with disease-causing bacteria, including those associated with food poisoning.

• Remove sources where flies can develop, such as trash or rotten fruit
• Add tight fitting screens to windows and doors
• Seal cracks on windows and ventilation openings
• Use traps in combination with sanitation and/or exclusion (traps alone will not work for control)
  

Mosquitos generally look for water and dark humid locations. They tend to lay eggs in still water, like that found in vases, puddles or bird baths, as well as slow moving water and moist areas that can flood.

Mosquitos are usually nuisance pests and don’t cause much harm, but their bites can cause itchiness and redness. Although West Nile Virus is uncommon, in Colorado there were 175 cases in 2021, 11 of which proved fatal.

• Remove standing water around the outside of your home
• Inside your home, deep clean or throw out items that contain water, such as vases or flowerpot saucers. If some things are unable to be drained, use pesticides to kill mosquito larvae.

Most moths found inside are common outdoor species that move indoors when seeking shelter. Two most common in Colorado are the miller moth and the Indian meal moth. 

Miller moths fly into homes during their migration season and Indian Meal moth larvae can be found in numerous dry foods, including pet food.

Miller moths can a nuisance, but die within a few days and do not reproduce indoors.

Indian meal moths do not feed on anything indoors, but their larva grow in dry food products. Continued occurrence of small moths in the home for periods longer than three weeks typically indicates infestations of Indian meal moth

Miller moths
During migration season, seal any openings, reduce light sources, and make sure doors and windows are closed. If moths enter they can be killed with swatters, vacuum cleaners, or you can wait for the insects to die on their own.

Indian Meal moths
The easiest ways to kill Indian Meal moths are:

• Freezing them by placing affected food into the freezer for a few days
• Warming up infected food in the microwave

All infected foods should be disposed of.

Spiders come indoors at the beginning of fall when temperatures go down. Depending on the species, locations where spiders are found vary. Generally spiders seek moisture, so are most often found in bathrooms, kitchens and basements.

In most situations spiders aren’t a problem to humans. However, exceptions include spiders that have venom that can impact humans, such as black widows and brown recluse (brown recluse are not common in Colorado).

From a biological standpoint, it is rarely necessary to control spiders. However, if it is desirable to get rid of spiders in the home, a combination of sanitation and pesticides should be effective.

• Remove structures where spiders can hide and reproduce outside of your home, such as, rocks, wood piles, and other shelter objects around the outside of your home
• Stop migration of spiders by covering cracks and crevices that lead into the home
• Screens and doors should be fully sealed when closed

Stink bugs can overwinter in mass in cracks and crevices within buildings. They also lay their eggs in host plants.

Stinkbugs are nuisance pests. They group indoors over winter. When smashed or squished they emit an unpleasant odor. Additionally, they can cause damage to host plants. 

• Seal areas of home where stinkbugs can enter, like cracks and crevices around the home
• Vacuum stinkbugs inside and outside the home instead of smashing the to avoid odor release
• If possible avoid having host plants around the home