CONSTRUCTION BASICS: Pests Of New Construction

Features - PCT News

A new home sometimes has a different set of pests than an established residence. Here are some examples of what pest management professionals may find in these locations.

April 12, 2002

Often, when canvassing a new neighborhood for new accounts, we hear, “Sorry, I don’t need your service. This is a new home!” The reality is that new buildings often have a number of pests in and around them. These pests can include insects, spiders and other arthropods, as well as vertebrates. When considering pests of new construction, there are three distinct periods to consider: pre-construction to completion, fresh or just completed construction and recent construction (generally less than two years old). Each of these periods will have different pest problems associated with the habitat and the construction practices employed. These pests can be grouped as follows: displaced wildlife, inadvertently trapped organisms, opportunistic pests and built-in pests.

PEST ACTIVITY DURING CONSTRUCTION. Generally speaking, there is no such thing as “empty land.” Ants, termites, weeds, mice and dozens of other organisms compete for resources and territory on each acre of property. Just because humans designate a piece of property as a construction site and then proceed to resurface it does not change the fact that organisms are present.

It may be advisable to implement a pest elimination program prior to breaking ground in order to clear the construction site of its resident pest population. When the proposed site is close or adjacent to residences, some pests may be driven to adjoining properties if service is omitted. Therefore, many cities have regulations requiring that a rodent control program be established prior to breaking ground. In some parts of the country, an existing fire ant infestation may delay construction as the ants defend the building site from construction. In some regions, there are so many termite colonies (often referred to as “termite pressure”) that lending institutions require pre-treatment of all construction pads as a condition of closing the loan. In these regions, it is not uncommon to see termite tubes climbing the concrete slab, sill plate and wall studs before the home is completed. This will be remedied when the final grade (an exterior perimeter soil treatment) is performed.

Poor sanitation by construction crews may lead to new infestations of flies, mosquitoes, bees and rodents on the site. Abandoned food containers attract these pests and may even attract feral cats and dogs or wildlife, such as raccoons and coyotes. Abandoned equipment and construction containers may provide harborage, allowing some of these pest species to establish themselves.

ACTIVITY IN FRESH CONSTRUCTION. When faced with pests of fresh construction, the pest management professional often finds arthropods and vertebrates that were trapped in the structure prior to completion of the structure, which may include mice and rats. These rodents sometimes establish themselves on the construction site if the project has taken a long time to complete. They nest in voids and use insulation, packing material and plastic foam containers for bedding material. Pack rats may also use scraps of wire and other construction materials.

Once construction is finished, these animals start foraging for resources and may gnaw through plastic plumbing lines to find water. Birds may also nest in soffits, copulas and under roofing tiles. Bats may also roost in these same places. Other trapped pests that may be found include a variety of spiders, crickets, outdoor cockroach species, ants, flies, moths, fleas and ticks. Ticks and fleas occur when feral dogs and cats, or wildlife, such as coyotes and raccoons, were frequent visitors to the construction site.

Depending on the region and the month of completion, clusterflies, paper wasp queens, ladybugs and boxelder bugs that were overwintering in the structure may begin to make an appearance as they attempt to exit the building. Also dependant on the season and how long the structure is lying vacant, some opportunistic pests may also become a problem. I once had a “spec” home located in the desert that sold after six months. The day of the closing, the new homeowner found hundreds of dead and living springtails and silverfish living in the home.

In addition, ants often invade fresh homes. Ants may have been on the property during construction and had construction workers destroy their mounds. When the structure is complete and the site is relatively quiet, the ants resurface and begin foraging. They are drawn to the structure by irrigation and the warmth of the building surfaces, or the shade caused by the structure. In southern Arizona, for example, it is not uncommon for most of the homes in a new housing subdivision to be attacked by ants in the first six months. The sudden loss of natural habitat may also cause problems with displaced wildlife.

In the same region, a common complaint of new homeowners is great horned owls waking the homeowners by hooting down the chimneys. Large populations of doves, which find themselves without a place to live, may descend upon a property by the dozens. Woodpeckers may also continue to claim their territory, beating on vent pipes and chimney caps. In my own Tucson, Ariz., subdivision, coyotes and snakes plagued the neighborhood for nearly a year post construction.

PESTS OF RECENT CONSTRUCTION. I once responded to calls from homeowners on Long Island, N.Y., that the home was overrun with bees or wasps. Some of these people described the wasps as “huge with long stingers.” Upon inspection these insects turned out to be horntails or ichneumonid wasps. These insects, collectively known as “wood wasps,” parasitize the larvae of wood-destroying beetles in trees. The long stingers are drill-like ovipositors used to bore through the bark of trees and puncture the grub beneath. The wood was then milled and incompletely dried before it was used in the construction. The mature wasps would then emerge from the wood, often cutting a hole in the drywall on the way out.

It is possible to find other bizarre wood-destroying insects in a new home. The use of exotic woods for molding, paneling, trim caps, shelves and cabinets can result in emerging polycons and powderpost beetles from South America and Asia. Often, new homes have new furniture, which may also be infested.
In one instance, a client had a dining room table that was infested with what appeared to be giant, ¾-inch lead cable borers from the Philippines. In another case, drywood termites swarmed from a coffee table imported to New York from Mexico. To make matters worse, the pest control company failed to identify the termites and performed several treatments for Eastern subterranean termites before noticing that the termites didn’t look right. Drywood termites don’t naturally occur in New York and no one thought to identify them.

Subterranean termites can also become pests of new construction as they find all the scrap lumber and other cellulose that was accidentally (or deliberately) buried in the soil adjacent to the structure. In regions where dirt-filled stoops are common, this can be a problem since the scrap lumber may be used as part of the fill to create the stoop.

Another common recent construction pest is dermestid beetles. These beetles find organic debris or dead rodents and insects that are hidden in wall voids. Short of opening the wall, the injection of insecticidal dusts is about all that can be done for these pests.

As can be seen from the above examples, new construction can actually be a good sales lead for a pest control professional, if he or she knows what they are looking for. Remember, the first company that gets in with an owner of new construction often gets a customer for life. Do good inspections, ask lots of questions and use your imagination. It’s worth the effort!

The author is owner of American Environmental Services, LLC, Tucson, Ariz., and can be reached at