- (301) 829-0060
- Mt. Airy, MD
- info@pestshieldinc.com
Pest Shield, Inc. (MDA #30263, MD Certified #19058) has been treating fly infestations and general pest pressure across Frederick County since 2011, with over 75 years of combined pest management experience on staff. Owner Troy Yowell brings approximately 35 years of hands-on experience to every job, and on-staff entomologist Jeffrey Allwine provides species-level identification when field diagnosis isn’t conclusive — a capability most small pest control companies have to outsource. Pest Shield holds a 5.0 rating across 338+ reviews and has been recognized as Best of Frederick and a Nextdoor Neighborhood Favorite four consecutive years running.
How it works
Four steps. No surprises. Same answer whether it's your first call or your tenth.
You reach Troy or someone on his team directly. No call center, no dispatcher, no routing.
Same-day or next-day for most calls. Emergency stinging-insect situations and real-estate WDI deadlines get priority.
We identify the species, locate entry points, and find the source — not just the symptom.
Written recommendation, straightforward pricing, no obligation. If you don't need treatment, we'll tell you.
Flies appearing in volume indoors — especially when cleaning and DIY sprays haven’t made a dent — usually mean the source hasn’t been addressed. In New Market, the specific fly type matters, because each one points to a different driver and requires a different response.
New Market’s combination of older housing stock, agricultural surroundings, and wooded residential lots creates consistent fly pressure that tends to return season after season without a treatment approach that addresses the exterior environment, not just the interior symptoms.
60+ years of combined experience. Tell us what you’re seeing — we’ll come look, no obligation.
Pavement ants raided our basement this morning and I was desperate for someone to come today! After calling around and being told they recommended a quarterly service before even seeing our problem and couldn’t come out until Thursday(!!!) I called pest shield and they came this morning. He explained the problem and found the source. He sprayed the area and around the house and doesn’t think we need a service plan. He is also knowledgeable about mosquitoes. Call them!!
Elise Richard · June 2024 Read on Google →
Troy was very responsive to our flea issue, and very understanding of our concerns (a crawling baby in the house). Would recommend Pest Shield to others for sure.
hannah murray · September 2013 Read on HomeAdvisor →
Troy inspires confidence, not only because of his familiarity with the natural world (put our flea infestation in context with other reports he’s had and other signs he’s seen of impending harsh winter), but also his conscientiousness. He wanted to check that we really had fleas (visible on our white dog) before taking money to treat for them. Also, was straightforward about the one-time cost and possible follow-on treatments, if necessary. So far, we haven’t seen a single live flea since the single treatment, but if we have them or any other unwanted residents, we’ll call Troy. He even called to check up on the results. Impressed, highly recommend.
Carolyn Johnson · November 2014 Read on HomeAdvisor →
General pest & rodent control
Pest Shield’s approach starts with a free inspection — identifying which fly species is present, locating the source or breeding environment, and assessing the exterior conditions driving the problem. That distinction matters: house fly treatment, cluster fly exclusion, and drain fly remediation each require a different strategy, and treating the wrong target wastes time. Troy Yowell or one of Pest Shield’s technicians walks the property, checks entry points and structural gaps, and explains what’s driving the infestation before any treatment is recommended.
Treatment is exterior-first. Pest Shield treats the home’s perimeter and exterior surfaces to intercept flies before they establish indoors — keeping chemical contact inside the home minimal. As one longtime customer described it: “Pest Shield treats your house primarily from the outside to prevent pests from ever getting into your house and keeps the chemicals out of your home, protecting your family.” For cluster flies specifically, exterior treatment targets overwintering entry points — soffits, window frames, exterior trim gaps — before flies can establish in wall voids. For house fly pressure driven by agricultural surroundings, perimeter treatment disrupts the approach and entry cycle that sustains indoor populations.
| Fly Type | Primary Driver | Treatment Focus |
|---|---|---|
| House fly | Organic breeding material nearby (livestock, waste, compost) | Exterior perimeter treatment; source identification |
| Cluster fly | Overwintering in wall voids and attic spaces via building envelope gaps | Exterior treatment targeting entry points; perimeter barrier |
| Drain fly | Organic film in drains, sump pits, or crawl space moisture | Source identification; drain treatment; moisture assessment |
After initial treatment resolves the active population, Pest Shield offers enrollment in the Standard Care Plan — treatment every 60 days on a bi-monthly cadence, exterior-focused, with a 100% effective guarantee. If fly activity reappears between scheduled visits, Pest Shield returns at no charge. You don’t need to be home for scheduled treatments. For New Market homes dealing with seasonal cluster fly pressure or recurring house fly activity from agricultural surroundings, the 60-day cadence is calibrated to interrupt the seasonal cycle before populations re-establish — rather than responding reactively each time pressure builds.
Pest Shield uses EPA-approved products throughout. Nontoxic bio-pesticide options are available for households with children and pets, and the exterior-first approach means interior chemical exposure is minimal in most fly treatment scenarios.
Owner
Founded Pest Shield in 2011 after years as a pest management contractor on U.S. military bases in Iraq and Afghanistan. Around 35 years in pest management. Personally handles or leads the majority of service calls.
Pest Management Specialist
Field technician handling residential and commercial service calls across Frederick, Carroll, and Montgomery counties.
Pest Management Specialist
Field technician handling residential and commercial service calls across the service area.
Our Entomologist
Consulting entomologist on species identification, conducive conditions, and treatment strategy for difficult cases.
New Market sits at the eastern edge of Frederick County along Route 144 — the old National Road — where the suburban fringe gives way to agricultural land, wooded residential lots, and rural properties. Pest Shield is based in Mt. Airy, just a few miles west on the same corridor, making New Market a natural part of its core service area with same-day and next-day response times that larger regional companies can’t consistently match.
The town’s older housing stock and proximity to working farmland create a specific fly pressure profile. Cluster flies exploit the less-sealed building envelopes common in historic and older homes along the National Road corridor. House fly populations on New Market’s rural edges are sustained by nearby livestock operations, hay storage, and composting — organic breeding material that persists through the warm months regardless of how clean the home is kept indoors. Residents dealing with broader seasonal pest pressure alongside flies often benefit from pest control in New Market that addresses the full range of pests active in this environment.
It matters significantly, because each fly type has a different source and requires a different treatment approach. House flies (Musca domestica) are the familiar large flies that hover near food, trash, and exterior doors — they breed in organic waste outdoors and enter in search of food. Cluster flies (Pollenia rudis) are slightly larger and slower-moving, typically appearing in upper rooms or near south-facing windows in fall and on warm winter days — they overwinter in wall voids and attic spaces and don’t breed indoors at all. Drain flies are small and moth-like, hovering near sinks, floor drains, or basement utility areas — they breed in the organic film inside slow or unused drains. If you’re not sure which you’re dealing with, Pest Shield’s free inspection identifies the species and locates the source before any treatment is recommended. On-staff entomologist Jeffrey Allwine is available for species-level identification when field diagnosis isn’t conclusive.
DIY sprays kill adult flies already indoors but don’t interrupt the breeding cycle or address what’s drawing flies to the home in the first place. If the source — organic material near the structure, a moisture issue feeding drain fly breeding, or gaps in the building envelope that cluster flies are using to overwinter — is still active, the population will rebuild. Pest Shield’s exterior-first perimeter approach targets the entry and approach cycle rather than just the interior symptom, which is why results tend to hold where repeated self-treatment hasn’t.
Pest Shield uses EPA-approved products and offers nontoxic bio-pesticide options for households with children and pets. The exterior-first treatment approach keeps chemical contact inside the home minimal in most fly treatment scenarios — the goal is to treat the perimeter and entry points, not the interior living space. Troy is documented proactively flagging safety considerations for families with young children and immunocompromised household members, and will walk you through what’s being applied and what precautions apply before treatment begins.
It depends on the fly type and what’s driving the pressure. A single treatment can resolve an isolated cluster fly emergence or a drain fly situation once the source is addressed. For house fly pressure sustained by agricultural surroundings — which is common on New Market’s rural edges — the underlying conditions don’t go away between seasons, and a single treatment addresses the current population without preventing the next cycle. Pest Shield’s Standard Care Plan (treatment every 60 days, exterior-focused, 100% effective guarantee, free retreatment between visits if activity reappears) is designed for exactly that situation: maintaining results through seasonal pressure rather than responding reactively each time flies build back up. Troy will tell you honestly whether ongoing service is warranted for your specific situation — if it isn’t, he’ll say so.
No — Pest Shield’s exterior-first treatment approach means scheduled visits under the Standard Care Plan typically don’t require you to be home. The treatment focuses on the perimeter and exterior surfaces of the home, so access to the interior isn’t needed for most routine fly control visits. For the initial inspection, having someone present is helpful so Troy or the technician can walk through what they’re finding and explain the treatment plan — but for ongoing scheduled visits, you can go about your day.
