Pest control for Gaithersburg homes, townhouses and apartments

Which pests come up most often around Gaithersburg?

Four groups account for most calls: eastern subterranean termites, which is the termite species reported for Maryland; mosquitoes, led by the Asian tiger mosquito; ticks, with the blacklegged, lone star and American dog ticks named by the state as the ones most likely to bite people; and rats and mice.

Alongside those are the pests that live indoors all year and have nothing to do with the weather: cockroaches in warm kitchens and utility rooms, bed bugs moving between units, ants following a water line in, and wasps building where a soffit or a shed gives them cover. Those are the everyday work of general pest control.

Two have a date rather than a season. Carpenter bees look for nest sites in April and May and favour bare or weathered wood, which is why a deck rail or an unpainted fascia is where you find them; Extension notes they are pollinators and not aggressive, so treatment is for wood being damaged, not for a bee near a flower. Brown marmorated stink bugs fly to overwintering sites from mid-September into the fall, and they do not bite.

• Spring: termite swarmers after warm rain; carpenter bees scouting bare wood in April and May.
• Warm months: Asian tiger mosquitoes in containers; ticks on shaded ground and trail edges.
• Mid-September onward: stink bugs at sunny walls and windows, looking for a way in.
• Year round: rats and mice, cockroaches, bed bugs and ants indoors.

What does a termite swarm in spring actually mean?

It means a mature colony is close by. University of Maryland Extension describes swarmers as the sign of a nearby mature colony, and swarmers that get indoors die of dehydration rather than doing damage. The swarm is the signal; the colony in the soil is the problem.

An older report quoting state agriculture officials put the swarm window at roughly March to June after warm rain, and named the eastern subterranean termite as the species found in Maryland. Treat both as the long-standing picture rather than this year's forecast, but the practical point holds: a pile of wings on a sill in spring is worth a call even though the insects themselves are already dead.

A lender or a contract may want the finding in writing, and in Maryland a wood-destroying insect inspection is reported in writing on state Form MD-1. Whether one is required at sale is a question for your contract and your lender, not for this page. The inspection itself is covered under termite and wood-destroying insect inspection, and the signs are set out in the termite signs guide.

Can mosquitoes and ticks be treated here, or just tolerated?

Both can be reduced, neither is eliminated. The county's own position is that mosquitoes will remain part of the local environment. For the Asian tiger mosquito, the Department of Agriculture says it breeds in anything holding rainwater and that spraying helps only a little, so emptying containers does more than product does.

There is local precedent for the heavy version of mosquito work: in 2016 the Department of Agriculture, with the county health department, ran truck-based adult mosquito spraying in Gaithersburg, Wheaton and Sandy Spring alongside door-to-door breeding-site checks, and officials advised residents to empty water-holding containers. That was one past response and not a schedule you can expect, but it shows what the agencies themselves put first.

Ticks are a different kind of problem because the exposure is usually not in your own yard. The Maryland Department of Health names the blacklegged, lone star and American dog ticks as the ones most likely to bite people and advises daily tick checks and EPA-registered repellents; the county's Lyme page identifies the blacklegged tick as the one that spreads Lyme. A 2007 entomology note recorded lone star ticks at county parks including Rock Creek Regional Park, Wheaton Regional Park and Blockhouse Point, and notes lone star ticks are not involved in Lyme transmission. Yard work focuses on the shaded edges where ticks sit, which is tick control.

Who deals with rats, and what does the county require?

The property owner. Montgomery County's rat control guidance says owners are responsible for rat elimination and that the health department's vector control team does not supply poison or traps. Chapter 39 of the county code makes it unlawful to allow an infestation, or conditions that contribute to one, to continue.

That makes the first step a walk around rather than bait: bins without lids, pet food left out, a compost pile, water, and a run along a fence line or under a shed. Rats need very little, and the places they feed are usually easier to change than the places they nest.

If you rent, the route is different. Housing code enforcement at the county's housing department administers Chapter 26, the housing maintenance standards, and tenants with pest and rodent complaints are directed to the county's MC311 line. Tell the owner or manager in writing and keep a copy. What the work involves is on the rodent control page, and the county process is set out in the rat problem guide.