Posted on: Monday, November 22, 2004

Carpenter ants hard to get rid of

By Jan TenBruggencate
Advertiser Staff Writer

Q. We all know pests and rodents are plentiful in Hawai'i, but the ones that are really irritating in our home are those orange carpenter ants. We've tried various ant traps but the only ones that seem to work are the harsh sprays, which we don't want to use due to the pesticides in them. What are the best methods to eradicate these types of ants without using sprays? — Keith, Pearl City

A. The carpenter ant is Hawai'i's largest ant species, growing to about a half-inch in length. They are primarily found outdoors and nest in rotting wood or tree stumps or wood that has been hollowed out by termites. Their colonies often comprise only 20 to 200 individuals, with many queens.

The ants forage alone at night, feeding on small insects and most foods found in homes, including meat and grease. The appearance of six or more foraging worker ants is a good indication a nest has been established in your home.

Carpenters ants favor wall clocks, pianos, hollow-core doors, double walls, the toe space beneath built-in cabinets, cardboard boxes, suitcases and seldom-used dresser drawers. Once you locate the nest, use an aerosol pesticide equipped with a flexible hose and needle-nozzle. That will enable you to pinpoint the spray, more effectively killing the ants and keeping the pesticide from spreading farther than necessary.

Ant baits are poisoned food that the ants will take back to their colony. If they feed toxic bait to the queen, the colony is doomed. Most ant baits are not effective in eliminating carpenter ants, but you may have luck with products specifically formulated for this species.

Other common ant species in Island homes are host ants, glaber ants, crazy ants, big-headed ants, pharaoh ants, Mexican ants and red long-legged ants. To find out which species is in your home, contact a pest control company or capture a few ants in a jar and bring them to the Department of Health vector control branch or the University of Hawai'i cooperative extension service.

The keys to ant control include blocking off their entrances by sealing cracks between the floor and wall. Don't leave food out overnight, particularly pet food.

If you are concerned about toxicity, baits may be preferable to sprays. Some ants prefer sweet baits. Some prefer meat and grease, and won't take sweet baits.

Once you figure out what ant you have, you may be able to identify which bait will work. Or let pest-control professionals handle the job.

Reach Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766, e-mail jant@honoluluadvertiser.com or call (808) 245-3074.