Pharaoh ants defy pesticides but an exodus could yet commence

Richard Fagerlund

Saturday, May 28, 2005

Ask The Bugman

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Q: Help! Our home has been infested with pharaoh ants for eight years. The problem always worsens in the summer. Although the ants have been a nuisance throughout the house, they are concentrated in my kitchen. They have ruined many sealed and unsealed food items. Professional exterminators visited twice and sprayed chemicals on the walls and floor. That treatment resulted in only temporary control of the pest (I was only guaranteed control). We've lived with these pests too long. Is there any way to permanently rid our home of these tiny red ants?

B.L., Chicago

A: Pharaoh ants can be eliminated, but it is difficult and will take time. The mistake the exterminator made was spraying pesticides in the house. Pharaoh ant colonies often split up when they encounter pesticides and ultimately get worse. It is a shame the exterminator didn't know a little more about their habits in order to eradicate them.

Using baits can eliminate these ants. A good bait mix would be 2 parts peanut butter with 3 parts honey mixed with 1 teaspoon of boric acid per 6 ounces of mixture. Place the bait in short pieces of plastic straw set on the kitchen counters and other places where the ants forage. The bait can also be taped under shelves and cabinets. Take the switch plates off electrical outlets and tape or glue a piece of straw with bait to the inside of the plate, then reattach it.

Liquid and aerosol pesticides should never be used for pharaoh ant control. They will almost always exacerbate the problem rather than solve it.

If you don't want to mix your own bait, you can buy bait specifically designed for Pharaoh ants (one source is It may take several months for you to get control using the methods I have outlined.

Q: We routinely remove one or two ticks from our dog. We also find them on our tile and our rug (wool) in or near areas where the dog lies. We are by no means overrun by the ticks. They don't seem to bother us. We are planning to have our Australian shepherd "trimmed and dipped." Is that wise?

G.K., San Francisco

A: I am not a fan of dipping animals, but I will leave that decision to your veterinarian. You may want to hire an expert to inspect your home and treat it for the ticks. You probably have the common brown dog tick, which rarely bites people but does like to breed in homes. If a pregnant female tick lays eggs unnoticed by you, you may end up with several hundred baby ticks in your home. Make sure whomever you hire has experience dealing with ticks. Ask for and check references of tick jobs they completed in the past.

Q: We have big black bees that bore into our wood patio cover frame. They have never bothered us, or us them. The other day I was standing close to the area where they were working, and one buzzed by my face very close and sprayed me with a clear yellow liquid that smelled yucky. Was the bee warning me off or do they urinate and I just happened to get in the way? Not too often you get sprayed by a bee!

A.S., Sacramento

A: I never heard of a bee of any species warning you with a spray before stinging you. However, bees, like all organisms, have to relieve themselves occasionally and I imagine you were in the wrong place at the wrong time.

Q: I enjoy your columns in the paper, and have decided to cancel my regular pest control service. The only critters I really can't tolerate are centipedes. Are there nontoxic ways to get rid of these guys from around and inside my house? I have noticed many tiny centipedes near my front door, all dead or dying, probably from the stuff the pest control company used. Obviously they are still hatching.

I. L., Sausalito

A: They may not be baby centipedes. There are several species of small stone centipedes that never get close to an inch long and are absolutely harmless. These centipedes feed on a variety of small bugs and should be considered beneficial. Installing door sweeps on your outside doors should prevent them from coming in. Pesticides are not necessary in this situation.

Q: I do some cleaning and maintenance at my son's small school, which has 40 children ages 5 to 11. The administrator recently got fed up with the ant problem and bought some Grant's Kills Ants sticks for use around the kitchen and bathroom sinks. According to the box, the active ingredient is arsenic. The maker claims the product will eliminate ants as well as wipe out their colonies.

Using your column and Web site, I've identified the ants as odorous ants, and in the past used a sweet bait with boric acid to control their population, although it did not eliminate them. Can you tell me what you know about Grant's Kills Ants bait, including its effectiveness and whether it is safe to use around young children? I'll pass your wisdom on to the administrator.

P.L. , San Francisco

A: Anything that contains arsenic is not safe to use around children. There are a variety of much safer baits that work well for odorous house ants. Please urge the administrator to remove the arsenic baits and find something safer. Advance Dual Choice (available from is a good bait for most species of ants.

Richard Fagerlund, a board-certified entomologist at the University of New Mexico, can be reached at and has a Web site at

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