I have ants in my office that start appearing each year around early March and are usually gone by early April. Generally they are the large, brownish, winged ants and come out of nowhere. They do not fly. They crawl around and I cannot track them to see where they are coming from. Sometimes there are also small, black ants (very tiny) that also cluster around - again, I cannot find where they are coming from. There is no food stored in my office. They do not appear to be in a line...and will appear suddenly on my desk, on the carpet, sometimes on windows. My question is how can I get rid of these?
Multnomah County Oregon
You can vacuum the ants you see because these are different than wingless ants which form 2-way trails as they wander the kitchen counter and more. These ants are reproductives – mating forms – which appear only once a year. Because you’re only seeing random ants that aren’t flying, they probably emerged during off-hours.
Because of their substantial size, I suspect they may be carpenter ants but I'm unable to verify that from your attached images. To verify their ID, please take 6 or so of the larger ants (females) and several of the smaller forms (males) to the Multnomah County Master Gardener Office in Montgomery Park, 2701 NW Vaughn St. Suite 450, Portland, OR 97210. Phone 503–445–4608. Hours are 10 AM to 2 PM, Monday through Friday, closed holidays.
In most cases, carpenter ants can be managed by removing wood damaged by excess moisture; replacing structurally unsound wood, improving ventilation, and eliminating moisture problems. Carpenter ants won’t take over-the-counter ant baits. You will likely need the assistance of a pest control company. See “Purchasing Pest Management Services” http://insect.pnwhandbooks.org/structual-and-health/purchasing-pest-management-services
You have time to evaluate the situation. For now, here’s some information about carpenter ants:
- Identification and Habits of Key Ant Pests in the Pacific Northwest: The section about carpenter ants, is on pages 5-6 with a good illustration in Figure 15. http://cru.cahe.wsu.edu/CEPublications/PNW624/PNW624.pdf
- Carpenter Ants: Their Biology and Control http://cru.cahe.wsu.edu/CEPublications/eb0818/eb0818.pdf