Bakersfield.com

Of all the household pests found in the San Joaquin Valley, Argentine ants can be one of the peskiest.  Like something out of a science fiction novel, these ants go far beyond their proverbial status as picnic pests, and show no bashfulness in creating their long, fast-moving trails inside and outside of local residences in their quest for food and water.

Argentine ants, Linepithema humile, are the most common of the sugar-feeding ants found in the lower San Joaquin Valley.  They can be recognized by the uniform size and grey color of the worker ants, and the trails they form.  This is in contrast to the southern fire ant, Solenopsis xyloni, which primarily feeds on foods high in protein.  Fire ants are red and black, worker size varies, and when disturbed, they have a characteristic behavior of swarming and biting anything and everything in the vicinity.

In order to effectively control Argentine ants, one must first gain an understanding of their biology.  Ants are highly social, meaning that they live in colonies of hundreds to thousands that work together for the common good.  At the top of the hierarchical chain are one or more queen ants, whose primary function is to populate the colony.  In the case of Argentine ant, multiple queens exist in each colony, with each queen capable of laying thousands of eggs during one season.  Any control strategies that do not kill the queens are nothing more than an exercise in futility.

Workers, on the other hand, are completely expendable.  Their function is to build the underground nesting area, forage for food and feed the queen and developing larvae.  Many people forget that in a large ant colony, hundreds of workers are born and die every day.  While it may be therapeutic to spray down an ant trail with a pesticide of choice and watch the ants flip on their backs and die, such actions result in inconsequential improvements in overall control; similar results can be attained by removing the food source and sucking up ants with a vacuum or wiping them up with a washcloth and a small amount of dishwashing soap or glass cleaner.

The most effective way to control Argentine ants is through the use of baits in bait stations.  This method tricks the workers into collecting pesticide-laced food that, when fed to the queens, either kills them or makes them sterile.  Advantages are that they are relatively safe to people, pets and the environment, and they can provide long-lasting control by stopping the development of new worker ants.  The primary disadvantage is that they don’t work immediately, as complete control cannot be attained until existing workers die off naturally.

Any pesticide-based baiting program should be coupled with cultural practices that help keep ants out of the home.  For example, cracks and crevices that allow the entry of ants should be caulked or otherwise sealed.  Outdoor plants should be pruned so that they do not come in contact with the house.  Attractive food items such as sugar, honey and pet food should be stored in clean, sealed containers.  Dishes should not be left in the sink for extended periods of time and garbage should be removed from the home frequently.

The trick with Argentine ants is to be persistent.  No single strategy works immediately, nor alone.  Try to use as many different management strategies as possible, keeping track of which work best in your particular situation.  Then, once the goal has been achieved, don’t let down you guard.  Argentine ants are very invasive and are constantly seeking out ways to expand their territory.  Small efforts towards preventing reinfestation around the home can save months of efforts to seek out another cure.

More information on how to manage Argentine ants, as well as other species of household ants, can be found at the University of California Integrated Pest Management Web Site at http://www.ipm.ucdavis.edu/..., or by contacting the UC Cooperative Extension office for Kern County at 661-868-6200.