Integrated Pest Management

IPM Manual for Home and Garden Pests in British Columbia

Chapter 11: Household Pests

Learning Objectives

When you have completed this chapter, you should be able to:

1. List the common household pests and describe their general appearance, damage they may cause, and the key features of their biology that are important for their management.
2. List methods to prevent these animals from becoming pests.
3. List preferred and other control measures for these animals.

Introduction

Household pests are often just a nuisance, but some are damaging to food or possessions. Even when pests do get into a house, the problem can often be solved without resorting to applying pesticides. It is particularly important to recommend non-toxic controls and prevention methods for indoor pests because unsafe or incorrect use of toxic pesticides by domestic users presents a greater danger from pesticide exposure than it would outdoors. Children are especially at risk when pesticides are used in their living areas. For stored products pests, the most effective measures usually involve removing the pests’ food supply and breeding sites. This includes cleaning up spilled food (especially pet food), tightly covering garbage containers, and freezing stored food and goods to eliminate infestations.

Serious flea or rodent problems, or established carpenter ant infestations, may require professional assistance from a licensed pest control service to eliminate the problem.

When suggesting pesticides for indoor use recommend the least-toxic products and ensure that the specific product is labelled for indoor use. Many products registered for use outdoors are not safe for indoor use.

Ants

Description

• There are many species of ants in BC and most are not a problem.
• Most ants are black or brown, though some are reddish or yellow.
• Ants are usually about 5 mm long (range 2 mm to 10 mm long).

Damage

• Ants are beneficial insects, but a nuisance when they get into homes.
• Ants enter homes to search for food (such as crumbs, sweet foods, pet foods, or kitchen garbage), some ant species may nest in or around home foundations.
• Ants usually only enter homes for a short period in the spring and early summer.
• It can take two to three weeks to see results with baits.

Biology

• Ant larvae are fed by "worker" ants, which are the ones that are seen searching for food.
• Ant nests may be in old tree stumps, under rocks or pavement or in soil outdoors.
• Ants leave invisible odor trails for other ants to mark the path to a food supply.

Prevention

• To avoid attracting ants, remove food by wiping jam and syrup bottles clean, cover garbage tightly, clean up food spills, seal opened food in containers with tight lids, or store the food in the refrigerator.
• To prevent ants from getting in a house, use caulking or weather-stripping to seal cracks and entry points around windows, doors, plumbing outlets in walls, along the bottom of siding, and on top of foundations.

Preferred Controls

• Find out where ants are entering and caulk or seal up entry points (often around windows
  or doors) and wipe up ants with soapy water to erase their odor trails.
• It is usually not necessary to destroy ant nests, but if necessary, ants can be driven out of nests in soil around the foundation by repeatedly flooding the nest with water.
• Set out ant baits containing boric acid, worker ants carry the bait to the nest.
• Place baits where ants will find them, but out of reach of pets and children.
• Apply a very light layer of dust products containing boric acid or silicon dioxide in cracks where ants enter—if kept dry, these products remain effective for years.

Note: It can take two or three weeks to see results with baits.

Other Measures

For severe or persistent infestations that do not respond to the above measures, consult a licensed pest control service to identify the species and recommend an integrated pest management program.

Carpenter Ants

Description

• Carpenter ants are common beneficial predators in forests in coastal BC.
• All local ant species are either entirely black, or have a reddish middle section.
• Worker ants are 6-12 mm long and queens are up to 20 mm long and have wings.

Damage

• Carpenter ants damage buildings by tunneling into water-damaged wood to make their nests.
• Carpenter ants are a nuisance when they search for food indoors (usually early spring).

Biology

• Queen ants fly in swarms during spring and early summer looking for sites to start new colonies.
• Most will die off without starting a nest. Most main nests are outdoors in moist, decaying stumps, trees, or landscaping timbers, where the permanently damp conditions are suitable for development of eggs and young ant larvae.
• Main nests are only found in houses where there is damp and decaying wood.
• Most nests in houses are satellite nests, which are offshoots from the main nest. Older larvae and pupae are reared in satellite nests because they tolerate drier conditions. These nests can be in ceilings, eaves, wall voids, or under insulation in attics and crawlspaces.

Prevention

• Remove and repair any wood damaged by water.
• Do not let siding or structural wood touch the soil.
• Do not stack lumber or firewood against a house.
• Remove all nearby rotted stumps or logs.
• Prune trees so branches don’t touch house.

Preferred Controls

• Find the nest and remove it manually if it can be reached.
• Vacuum up the ants or spray with pyrethrins to kill them. Signs of nesting are mounds of loose shavings or sawdust beneath cracks, and rustling sounds in walls (use a rolled up paper tube to listen for noises).
• Follow ants carrying white, oval young to find nests.
• Follow ants to the main nest where the queen lives (usually outdoors) and destroy the nest manually or apply pyrethrins.
• Prevent ants from re-entering by caulking entry cracks.
• Apply a very light dusting of boric acid or silicon dioxide in walls, cavities, and especially on house wiring and plumbing pipes (if possible), these are effective for years if kept dry.

Other Measures

For severe infestations or if nests cannot be found, consult a licensed pest control service that will use an integrated pest management approach.

Carpet Beetles

Description

• Larvae are oval or carrot shaped, dark brown, bristly, with a tuft of hair at one end, and slow-moving (5-13 mm long).
• Adults are oval, black beetles with brown marks on wing covers.

Damage

• Larvae eat holes in a wide range of natural fibres such as wool, cotton, fur, leather found in furniture, clothing, shoes, and carpets.
• Damage is usually concentrated in one area of an item (in contrast to moth damage, which is more scattered).
• Where larva are actively feeding, the site is littered with shed skins and specks of fecal materials.

Biology

• Eggs are laid on natural fibres in dark, quiet places, such as closets, cupboards, and
  under rugs.
• Eggs hatch in 2 weeks.
• Larvae feed for 6-24 months, depending on the species, temperature, and food supply.

Prevention

• Clean and properly store vulnerable materials.
• Seal cleaned fabrics in plastic bags to store them for long periods.
• Use traps instead of poison for rodents, to avoid a rodent dying in an inaccessible place where it would provide food for carpet beetles.
• Remove mouse, bird, and wasp nests in and around the home, which are a source of food.

Controls

• Wash or dry clean infested material or freeze items for a week to kill larvae.
• Clean and vacuum the area thoroughly, then dispose of vacuum bag.
• Apply dusts containing pyrethrins or silicon dioxide to cracks, crevices, floors, and household furnishings.

Fleas

Description

• Dark brown jumping insects (1 mm long).
• Fleas live on dogs, cats and other animals, feeding on blood.

Damage

• Bites are annoying and can cause allergic reactions in people and pets.
• Can spread pet parasites, such as tapeworms.

Biology

• Adults live on animals.
• Flea eggs fall off and hatch where the pet rests.
• The larvae live on flecks of dried blood in the pet bedding.
• Flea larvae take 1 - 7 months to develop, depending on conditions, then pupate.
• When they hatch into adults, they can bite people even though pets are not present.

Prevention

• Keep pets out of hard-to-treat areas, such as under porches.
• Don't allow pets to roam.
• Prevent stray animals from entering the yard.

Preferred Controls

• Vacuum frequently and thoroughly, dispose of vacuum cleaner bags after vacuuming.
• Shampoo or steam-clean carpets.
• Comb pets regularly with a flea comb.
• Wash pets with shampoos recommended by a veterinarian.
• Wash pet bedding in hot, soapy water every 2-3 weeks.
• Spray pet beds, carpets, and floor areas throughout the home with products containing methoprene, which stops development of larvae, and pyrethrins, which controls adult fleas.
• Treat the pet’s outdoor resting places.
• Apply insect parasitic nematodes to outdoor resting areas in the yard to control larvae.
• Set out light traps designed to attract fleas in areas where problems persist.

Note: Do not sell ultrasonic devices to repel fleas. They are not legally registered in Canada because there is no scientific basis for claims made for such devices.

Other Measures

Consult a veterinarian to have the pet placed on a program of oral flea medication. This is an insect growth regulator that can safely be fed to pets in pill form. A new, low toxicity topical flea insecticide is also available from vets who must apply it in the clinic.

For severe or persistent infestations that do not respond to the above measures, consult a licensed pest control service that will use an integrated pest management program.

Rats and Mice

Description

• House mice are small, slender animals with pointed noses, relatively large ears, and nearly hairless tails. Droppings are dark pellets, about 3 mm long.
• Black rats (roof rats) and Norway rats are twice as long as house mice. Rats are common in coastal areas of BC. The droppings are oval pellets 1-2 cm long.

Damage

• They gnaw on woodwork, insulation, siding, and can cause electrical short circuits by gnawing wiring.
• They eat stored food and contaminate it with their droppings and urine.
• Can transmit diseases on their feet or in urine.
• In some areas, fleas on the rodents carry disease.

Biology

• Rodents breed quickly, producing up to 7 litters of young per year.
• Mice make nests of shredded paper, insulation, or other soft materials, in hidden,
  enclosed spaces.
• Black rats nest in ceilings and attics.
• Norway rats prefer moist conditions and generally live at ground level.

Prevention

• Block all entry places from the outside with durable materials. Use heavy, welded wire mesh to cover vents, conduits, drains, and other openings that cannot be blocked.
• Eliminate potential hiding places near house foundation, such as firewood, equipment, and dense vegetation.
• Build rat-proof compost piles using heavy 1/2" welded wire mesh (not chicken wire).
  Do not compost meat scraps.
• Store outdoor garbage in tightly closed, preferably metal, containers.
• Place bird feeders well away from house and prevent seed spills onto ground.
• Stop rats from climbing feeder poles by placing wide metal collars on poles.

Preferred Controls

• Set many snap-traps at one time, small ones are available for mice, larger ones for rats.
• Bait traps with dried fruit, peanut butter, cheese, marshmallows, or onions.
• Set live traps or box traps, which are available for mice.

Note: Devices that emit ultrasound to repel rodents are not recommended because after the initial effect, rodents become used to the sound and learn to ignore it.

Other Measures

As a last resort, use rodent poison baits placed in tamper-proof bait stations. Baits must be placed in areas inaccessible to children, pets, and other animals. Use multiple-dose poison baits (with caution), including diphacinone, chlorphacinone, and warfarin.

Note: It is dangerous and illegal to scatter poison baits over the ground or inside buildings!

Customers should be warned about problems with baits, including:

• Poisoned rodents often crawl away to die in inaccessible places in homes, where they decompose and may smell and attract other pests.
• There is a risk of poisoning pets and wild animals that would catch and eat a rodent dying from poison.

Note: In areas where warfarin has been used extensively, rats and mice have become resistant to it.

For severe or persistent rodent problems that do not respond to the above measures, consult a licensed pest control service that will use an integrated pest management program.

Yellowjackets

Description

• Shiny, yellow-and-black striped wasps, 2 cm long.
• Beneficial predators of flies, caterpillars, and other pests.

Damage

• Stings are painful, also dangerous for people allergic to insect venom.

Biology

• In the spring, queen wasps build nests in the ground, in wall cavities or hanging from branches or eaves.
• Nests expand all summer as the population grows, but in September all of the wasps die off, except the queen, which overwinters under bark or leaf litter, but the old nest is not re-used.

Prevention

• Remove food that attracts wasps: feed pets indoors, keep garbage cans tightly covered and cleaned, bury fruit and table scraps deep in compost piles.
• Pick fruit early in morning or late in evening when yellowjackets are less active.
• Keep picnic food covered, cover drinks and drink only through straws in lids.

Preferred Controls

• Set out several yellowjacket traps to attract them away from outdoor picnics and barbecues. Bait traps with ham, fish, cat food, or meat scraps until August. Later in the season jam, honey, or rotting fruit usually works better.
• Remove nests early in the summer while they are small. Remove nests in the evening when wasps are less active. Wear head-to-toe protective clothing or employ a pest control service to remove the nest.
• If the nest is easily accessible, spray pyrethrins into the nest opening while wearing protective clothing. Repeat on successive evenings if necessary. Remove sprayed nests after killing wasps to prevent birds from eating poisoned larvae inside.
• If wasps are in the wall of a building, do not block nest openings as they can chew through into the house interior.

Other Measures

For inaccessible nests and those far enough above ground to require a ladder, a licensed professional pest control service should be employed to remove or treat the nest.