Ants can be active and invade structures anytime the weather is sufficiently warm, typically 50°F or warmer. One of the best ways to prevent the formation of large colonies of pest ants is to use a weatherable granular bait in a proactive perimeter treatment program.
If nonperimeter areas with conducive conditions such as heavy vegetation or woodpiles exist, these areas should be treated, too. The protocol also should include application to the structure of a microencapsulated pyrethroid. This two-pronged approach will take care of other occasional invaders in addition to ants.
If ants already are a problem at the structure, a three-pronged approach should be used. A nonrepellent should be applied 1 ft. up and 1 ft. out around the perimeter and on identified trails. An ant-labeled granular bait should be sprinkled on top of where the nonrepellent was sprayed on the ground. Lastly, a sweet gel or syrup ant bait should be applied along identified trails.