Fire ants: Masters of the Earth (10-26-09)

Considered one of the strongest animals in the world, ants have been digging through the earth for eons. It is estimated that ants worldwide dig up more than 16 billion tons of dirt annually. That is enough to fill three billion dump trucks. Now that we have dried out somewhat from the heavy rains, and cooler weather has arrived, fire ants have been busy elevating their mounds in preparation for winter. New mounds can appear overnight as a large colony of 100,000 carrying five times their own weight can excavate a six inch by six inch by six inch mass of dirt while making only five trips each.

Fire ant control is a never-ending battle across Mississippi, but with a good strategic plan and persistence you can keep them to a minimum in your lawn.

There are several methods of applying products that control fire ants such as mound drenches, dry mound treatments, or broadcast sprays or granules. Probably one of the most effective for homeowners in terms of costs and effort is granular baits applied three times a year (spring, mid-summer, and fall). Baits can be applied to individual mounds, but when broadcast across the entire lawn you also eliminate small undetected colonies that quickly replace the larger ones you individually treated.

Baits can provide 80 to 90 percent control when applied two to three times a year and a fall application now will eliminate many colonies before winter. If you have large colonies that need immediate reduction then individual contact insecticide mound treatments can be used in combination with baits, but wait at least a few days to allow the workers to bring the baits into the mound.

There are many trade name baits available containing at least one of the following active ingredients: hydromethylon, fenoxycarb, spinosad, pyriproxyfen, methoprene, or abamectin. Since baits generally use some type of oils for attracting ants it is important to use fresh baits and store them in cool dry areas so they don’t become rancid.

Extension publication - Control of Insect Pests in and Around the Home Lawn provides additional information on fire ant control and other home lawn insects.

Published October 26, 2009

Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. wwells@ext.msstate.edu