Spring in St. Louis is beautiful — blooming dogwoods, warmer evenings, and backyard cookouts. But it also brings a surge of pest activity that catches many homeowners off guard. As temperatures climb above 50°F consistently, insects that were dormant all winter become active, hungry, and looking for food, water, and shelter. Your home provides all three.
The good news: with a few proactive steps and the right timing, you can significantly reduce pest pressure this spring and avoid costly infestations down the road.
What Pests Are Most Active in Spring?
In the St. Louis metro area, these pests ramp up significantly from March through May:
- Ants — Odorous house ants, pavement ants, and carpenter ants all become active as soil temperatures rise. Ants send scouts into homes looking for food and water, and once they find a reliable source, the colony follows.
- Termites — Subterranean termite colonies that have been feeding all winter launch reproductive swarms in March and April. This is the most critical time for termite inspections in Missouri.
- Mosquitoes — Mosquitoes begin breeding as soon as standing water is available and temperatures stay above 50°F. In the St. Louis area, this often starts in March and hits peak levels by May.
- Spiders — Wolf spiders, brown recluse spiders, and other species become more visible in spring as they emerge from overwintering sites and follow the insect prey that is now active.
- Stinging insects — Wasps, yellow jackets, and carpenter bees start building nests in April. Early nest removal is far easier and safer than dealing with a mature colony in July.
- Silverfish and earwigs — These moisture-loving pests increase activity in spring, especially in damp basements, bathrooms, and crawl spaces.
10 Spring Pest Prevention Tips for St. Louis Homeowners
These steps take a few hours at most, and each one meaningfully reduces your risk of a pest problem this season:
1. Seal Entry Points Around Your Foundation
Walk the perimeter of your home and inspect the foundation for cracks, gaps, and openings. Pay special attention to where utility pipes, HVAC lines, and cables enter the structure. Use silicone caulk or expanding foam to seal gaps. Remember, mice can squeeze through a hole the size of a dime, and insects need even less.
2. Eliminate Standing Water
Mosquitoes breed in as little as a bottle cap of standing water. Walk your yard and dump, drain, or cover anything that collects water: flower pot saucers, bird baths (refresh weekly), clogged gutters, old tires, kids’ toys, and low spots in tarps or covers. This single step has a bigger impact on mosquito populations than any spray.
3. Clean Gutters and Downspouts
Clogged gutters create pools of standing water (mosquito habitat), promote wood rot (termite and carpenter ant attractant), and provide nesting material for pests. Clean them out in early spring and make sure downspouts direct water at least 3 feet away from the foundation.
4. Trim Vegetation Away From Your Home
Bushes, tree branches, and groundcover that touch your home’s exterior create bridges for ants, spiders, and rodents to enter. Maintain a 12-inch gap between landscaping and your foundation. Trim tree branches that overhang the roof — squirrels use these as highways to your attic.
5. Move Mulch and Firewood Away From the Foundation
Mulch retains moisture and warmth — ideal conditions for termites, ants, and earwigs. Keep mulch at least 6 inches from your foundation and no deeper than 2–3 inches. Store firewood at least 20 feet from the house and elevated off the ground.
6. Repair Screens and Weather Stripping
Inspect window screens, door sweeps, and weather stripping for tears, gaps, and wear. These are the most common entry points for flies, mosquitoes, and other flying insects. A varies roll of weather stripping is a lot cheaper than a pest treatment.
7. Address Moisture in Basements and Crawl Spaces
Many pests — termites, cockroaches, silverfish, earwigs, centipedes — are attracted to moisture. If your basement or crawl space is damp, use a dehumidifier and ensure proper ventilation. Fix any leaking pipes or faucets promptly. Moisture control is one of the most effective long-term pest prevention strategies.
8. Store Food Properly and Keep Kitchens Clean
Ants and roaches are drawn to food residue. Store dry goods in airtight containers, wipe down countertops nightly, sweep floors regularly, and do not leave pet food out overnight. Clean behind and under appliances — these are prime harborage spots for German cockroaches.
9. Schedule a Termite Inspection
Spring is the most important time for a termite inspection in Missouri. Swarm season peaks in March and April, and an inspection before or during that window catches problems early. Roberts Pest Control offers free termite inspections — there is no reason to skip this step.
10. Start Mosquito Treatments in March
Most homeowners wait until June or July to think about mosquitoes — by then, the population is already established. Starting barrier treatments in March disrupts the early breeding cycle and keeps populations low through the entire season. Roberts’ seasonal mosquito program runs March through October with monthly treatments.
The Value of a Year-Round Prevention Program
Individual spring cleaning steps help, but the most effective pest prevention is a consistent, professional treatment program. Roberts Pest Control’s R.O.S. (Roberts Ongoing Service) program provides bi-monthly treatments timed to St. Louis seasonal pest pressure. Each visit includes a perimeter treatment, interior inspection, and targeted applications for any active issues — all covered under a service guarantee.
Starting a prevention program now, before spring pest pressure peaks, means you stay ahead of the problem instead of reacting to it.
Start Your Pest Prevention Program Today
Spring pests are already waking up. Give Roberts Pest Control a call to schedule your free inspection and learn about our R.O.S. bi-monthly program. We serve homeowners throughout Jefferson County, St. Louis County, St. Charles County, and surrounding areas.
(636) 243-0900 • (314) 967-BUGS
Roberts Pest Control • Locally Owned & Operated • Festus, MO
Serving the Greater St. Louis Metro Area Since 2003