Argentine Ants Never Really Leave Richmond — Here's Why

One giant colony

The ants trailing across a Richmond counter are almost always Argentine ants. What makes them so hard to shake is that they don't form one tidy nest, they build massive, interconnected supercolonies that can stretch across yards and whole blocks, sharing workers and queens. The line you see indoors is a tiny fraction of it.

Richmond's mild, bay-moderated climate means the colony rarely gets a hard freeze, so it persists year-round instead of dying back each winter. That's why the ants seem to never really leave.

Why they come inside

Argentine ants nest outdoors under mulch, pavers, potted plants, and irrigation lines. They come indoors chasing moisture and food, during summer dry spells when outdoor water disappears, and again during winter rains when their outdoor nests flood. Kitchens, bathrooms, and windowsills are the usual entry.

Because the nest is outside and enormous, wiping the trail or spraying it accomplishes nothing lasting, and repellent sprays actively make it worse.

What actually reduces the colony

Repellent sprays cause Argentine ants to 'bud,' splitting into new satellite nests, so you trade one trail for several. The approach that works is the opposite: slow-acting bait the foragers carry back to share through the colony, plus a non-repellent perimeter product the ants cross without detecting and spread nest to nest.

Alongside treatment, trimming plants off the house, fixing irrigation and plumbing leaks, and sealing entry points around windows and slab edges keeps the next wave from finding a way in. A local exterminator works the colony, not just the counter.

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