Ants in the Lawn: Why Most Are Beneficial and When to Actually Worry

Ant hills across your Massachusetts lawn—small, brown, non-biting—are likely native species, not pests. Of ~100 ant species in MA, only three carpenter ant species damage structures.

Ants Are Ecosystem Engineers

• Soil aeration and mixing—often exceeding earthworms.
• Nutrient cycling—they move organic matter and minerals.
• Seed dispersal—critical for many native plants.
• Pest predation—they eat flea larvae, fly maggots, and other pests.

Don't Spray

Insecticides fragment colonies (creating more nests), kill beneficial insects, and contaminate soil. Massachusetts Department of Agriculture advises against spraying.

When to Act

Only if you confirm carpenter ants nesting in structural wood. Contact a pest professional for ID. Otherwise, leave them—they're working for you.