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Pest Control/Argentine ants


QUESTION: Like many San Diegans I am dealing with an annual summer attack of Argentine ants. As usual they are a problem in the kitchen, front entrance and living room downstairs. What's different this year is they've invaded new areas including the second floor.

I have used Grant's Stakes with some success in the past so I ordered some. In the meantime I went outside to investigate activity near the house and found 3 conga lines, one of which disappeared into the stucco of the house. Should I assume this means part of the colony is inside the walls, and that I need professional extermination?

By the way I have an indoor cat so I have to be careful.


The new paste/gel baits will work much better than the stakes (see for a series of articles about ant control). You probably don't need a pest control company because if they know what they are doing they'll use the baits, if not then it will be a waste of money. You can do the baiting yourself for less money.

Jack DeAngelis

---------- FOLLOW-UP ----------

QUESTION: Interesting. I used Terro liquid baits. After a few days, two baits upstairs stopped the second floor invasion but downstairs, some are taking the bait while others seem to be bypassing them and wandering around the room even though there's no food or water. Should I set out more baits in the room or just be patient?

You might try a protein-based bait such as Advance 375A outside as well (see for source). Terro is sugar (carbohydrate)-based and some ants prefer protein-based baits. The ants on the second floor may have had a nest in the walls whereas the ants on the first floor may be coming in from outside.

Jack DeAngelis  

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Jack DeAngelis


I can answer questions about the control of pest insects, spiders, mites and related arthropods. These household pests include termites, carpenter ants, powderpost beetles, nuisance ants, bed bugs, cockroaches, fleas, wasps, and many others. I can also answer questions about using pesticides and other pest control tools such as baits and traps.


I am a retired university extension entomologist. I've taught and conducted research in urban and agricultural entomology. I've published over 70 extension publications, 20 research publications and several books about insects.

Ph.D. in Entomology

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