Is yard spraying for ticks and mosquitoes worth it? What health agencies say

Updated November 10, 2026 · KeystoneProGuide editorial team

Does spraying the yard protect you from ticks?

Partly, and the CDC is careful to say so. It says pesticides can reduce the number of ticks in the treated parts of a yard, but that you should not rely on spraying to reduce your risk of infection. Before any spraying, it suggests checking with local health or agricultural officials about the best time to apply, the best type of product, and the rules for treating residential property.

The reason it matters in Pennsylvania: the state Department of Health says deer ticks, which spread Lyme disease, are found in every county, even in urban green spaces, and that Lyme disease is one of the most common reportable infectious diseases in the state. The department says the CDC estimates actual cases are about ten times those reported, which would mean around 100,000 a year in Pennsylvania.

What do the agencies put before spraying for ticks?

Changes to the yard, and to habits. The CDC's landscaping steps to reduce blacklegged ticks are:

remove leaf litter;
clear tall grass and brush around the house and at the edge of the lawn;
put a 3-foot strip of wood chips or gravel between the lawn and woods;
mow often;
stack wood neatly in a dry place;
keep play equipment, decks and patios away from the yard's edges and trees;
fence out deer, raccoons and stray dogs;
remove old furniture, mattresses and trash.

On habits, the CDC advises EPA-registered repellents, and the state Department of Health adds permethrin-treated clothing and checking yourself, children and pets after time outdoors. The department says a tick must stay attached for at least 36 to 48 hours to pass on the Lyme bacteria, which is why prompt checks help. The CDC says showering within two hours of coming indoors has been shown to reduce the risk of Lyme disease, and that ten minutes in a hot dryer kills ticks on dry clothes.

Timing matters too. The Department of Health says Pennsylvania ticks are most active from April to August and again in October and November, and can be active whenever the temperature is above freezing.

Does spraying the yard work for mosquitoes?

The agencies favor working on the water first. The EPA and CDC, in their joint approach to mosquito control, say the best approach uses every stage of the mosquito's life, and that egg and larva interventions are generally the most effective, least costly way to control mosquitoes. Around a house, that means getting rid of standing water in gutters, tires, buckets and toys, and changing the water in birdbaths, fountains, wading pools and plant trays at least once a week.

Pennsylvania's Department of Environmental Protection gives the same list and adds: drill holes in recycling bins, clean clogged gutters each year, and keep unused pools chlorinated. For water you cannot drain, it says products containing Bti, a naturally occurring bacterium sold in garden and hardware stores, kill larvae and are safe for people, pets, aquatic life and plants.

Mosquito control is also a public job. DEP runs a mosquito-borne disease program with county coordinators, tests mosquitoes for West Nile virus and sprays when testing shows a risk, as it did in parts of Delaware County in July 2026. Several counties run their own programs; see the county guides.

What about automatic misting systems?

The EPA is plain about them. It says outdoor residential misting systems have not been studied enough to document that they control mosquitoes or other yard pests, and have not been proven to control or prevent West Nile virus. The products most used in them can kill beneficial insects such as honeybees, ladybugs and butterflies, and one common ingredient is very highly toxic to fish. The EPA says no pesticide should be regarded as 100% risk free, that it does not regulate the misting equipment itself, and that you should ask your state pesticide agency before buying one or hiring a company to install it.

If you hire a company to spray, what should you ask?

Which product, and is it labeled for this use? Pennsylvania's regulation forbids using a pesticide in a way inconsistent with its label, and forbids applications where weather means the product can be expected to drift off the site.
How long should children and pets stay off the lawn? The EPA says to keep them away from treated areas as the label directs.
Will my neighbors be notified? In Pennsylvania, people on the state's pesticide hypersensitivity registry whose home, workplace or school is within 500 feet must be notified 12 to 72 hours before a commercial application.
Who is the certified applicator? Ask to see the card.
What will you do besides spray? A company that recommends removing leaf litter, brush and standing water is following the agencies' advice.

The regulation also lets a neighbor whose property borders a lawn or tree treatment within 100 feet ask the lawn or tree company, in writing, to be told before each application. That right covers lawn and ornamental treatment businesses, not every pest control company.

For the seasonal calendar, see how often and when, and for safety precautions around pesticides, see DIY or hire.

Sources

Preventing Tick Bites, U.S. Centers for Disease Control and Prevention
Lyme Disease, Pennsylvania Department of Health
Learn More About Ticks, Pennsylvania Department of Health
Mosquito Misting Systems, U.S. Environmental Protection Agency
Success in Mosquito Control: An Integrated Approach, U.S. Environmental Protection Agency
Department of Environmental Protection to Conduct Mosquito Control in Delaware County, Pennsylvania Department of Environmental Protection
Mosquito-borne Disease Control Program, Pennsylvania Department of Environmental Protection
Pesticide Hypersensitivity Registry, Pennsylvania Department of Agriculture
7 Pa. Code Chapter 128. Pesticides, Commonwealth of Pennsylvania (Pennsylvania Code)
Read the Label First: Protect Your Pets, U.S. Environmental Protection Agency