How to tell you have them
The Florida carpenter ant is large, up to about half an inch, with a reddish orange head and thorax and a black abdomen; locals sometimes call it the bull ant. It forages at night in long trails along fences, utility lines, tree branches touching the roof and the edges of patios, and it bites if handled. Inside, you may see a few large ants in the kitchen or bathroom at night, or find small piles of wood shavings and insect parts below a wall or soffit.
What they damage
Carpenter ants do not eat wood. They hollow it out to make room for the nest, and they prefer wood that is already damp or rotting: around leaking windows, under roof leaks, in fascia boards and hollow doors, and in the boots of palm trees. Finding them in the house is often a sign of a moisture problem worth fixing.
What treatment looks like
We follow the night trails to find the nest, which is often outside in a palm, a stump or a pile of wood. We treat the nest directly when we can reach it, place baits along the trails, and apply a non-repellent treatment where the trails meet the house, so foragers carry it back. Trimming branches and palm fronds that touch the roof, and repairing damp wood, keeps them from moving back in.
How long it takes
Activity usually drops within one to two weeks, and the trails stop within about a month as the colony declines. Nests inside walls can take a few visits.
Florida notes
Carpenter ants are most active on warm nights from spring through fall. Pinellas yards with mature palms and oaks give them plenty of nesting sites, which is why we look up as well as down. Carpenter ants are covered on every plan, starting with Quarterly.