Pest Control in Maryland Heights, Missouri

A budget line that became a policy

During the budget process for 2022, the City of Maryland Heights decided not to fund the purchase of mosquitocide — the chemical dispensed by a truck-mounted sprayer to kill adult mosquitoes.

The city named three factors. The availability of the material was one, and there was a concrete reason for it: due to supply issues, the city had been unable to locate and purchase the mosquitocide product in 2021. The impact on pollinators was the second. The city’s ongoing sustainability efforts were the third.

Mosquito control in Maryland Heights sits under Public Works rather than a city health department, and the city now directs residents to St. Louis County for information on mosquito breeding, eliminating standing water and control products.

The pollinator problem, stated plainly

The city was specific about what troubled it, and the mechanism is worth understanding because it applies to any adulticide, municipal or private.

Mosquitocide spray kills adult mosquitoes when a droplet touches the mosquito. That is the whole mode of action — contact with an airborne droplet. The difficulty is that those droplets do not discriminate. They would also come into contact with a wide variety of pollinators, causing their death.

The city had already tried to manage this by scheduling. The sprayer was previously run in the evening, when most pollinators are less active. That mitigates the problem rather than solving it, which is evidently how the city came to see it.

One clarification the city offered is worth repeating, because it changes the scale of the concern. Most people associate the word “pollinator” with honey bees. Pollinators are in fact a wide variety of insects, including bees, butterflies and moths, and they matter for the growth cycles of flowering plants generally.

What the city put in its place

Maryland Heights did not simply stop and say nothing. It published a list of steps residents could take instead, and it is more interesting than the usual advice because several items are habitat rather than chemistry.

Remove standing water is the first and least surprising — check for pails, buckets, toys and anything outside that holds water, bring them in or turn them over, and make sure downspouts and gutters drain properly rather than holding water.

Then the city recommends installing a bird house, on the basis that mosquitoes are part of the diet of many bird species and increasing the number of birds around a property helps reduce the mosquito population. It recommends installing a bat house for the same reason, with the added point that bats feed at night, when mosquito activity is higher.

For anyone with a decorative pond, the guidance is to keep it stocked with goldfish, koi, minnows or guppies, which feed on mosquito larvae in the water. For anyone with a swimming pool, keep it properly chlorinated and keep the pool cover free of standing water — a cover that pools rainwater is a breeding site sitting on top of a treated one.

The last suggestion is the one people tend not to expect, and it costs nothing to try: keep a fan handy. A light fan at ground level on a patio or deck helps in two separate ways. The moving air dissipates human scent and carbon dioxide, which makes it harder for mosquitoes to locate you, and mosquitoes are weak flyers, so the breeze makes it physically difficult for them to stay in the area.

ZIP codes served in Maryland Heights

A dispatch match is made to the address rather than to the city name, which matters in an area where municipal boundaries and bottomland run together.

What the county still does here

The city continues to contract with the St. Louis County Department of Public Health for vector control. Under that arrangement the county performs adult mosquito surveillance and carries out larvicidal treatment of the mosquito breeding sites it identifies.

That is a meaningful distinction for a household trying to work out what is covered. Surveillance and larviciding target the sites producing mosquitoes; they are not a service that treats a private garden on request. The city’s own summary of the whole question is the sentence to carry away: the best approach in reducing the mosquito population is to reduce the number of mosquito breeding habitats.

Structural pests sit entirely outside that arrangement. Termites, rodents, ants, cockroaches and bed bugs are private-sector work here, and the county programme has no role in them at all.

If something goes wrong, the complaint has an address

Most people never need this, but almost nobody knows it, and a page about a city that changed its pesticide policy is the right place to say it. Pesticide use in Missouri is regulated by the Missouri Department of Agriculture through its Bureau of Pesticide Control, at P.O. Box 630, Jefferson City. That is the body responsible for licensing, training and monitoring commercial applicators in the state.

University of Missouri Extension suggests calling the Bureau to run a background check on a company before hiring it — which is a better use of it than complaining afterwards.

Two statutory points are worth knowing if a dispute ever does arise. The state requires a certified commercial applicator or their employer to keep records of pesticide applications, including those made under direct supervision by licensed technicians and trainees, for three years from the date of application, and to furnish copies to the director on written request. And the Missouri Pesticide Use Act states expressly that nothing in it relieves any person from liability for damage to the person or lands of another caused by pesticide use — even where that use conformed to the director’s own rules and regulations. Compliance is not a defence to damage.