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Gardening | How you can put out the ‘fire’ in fireants

Recent heavy downpours have triggered the rise of fire ant nests closer to the ground’s surface.
Recent heavy downpours have triggered the rise of fire ant nests closer to the ground’s surface. KRT

Recent heavy downpours have triggered the rise of fire ant nests closer to the ground’s surface. Most of these nests have been active underground for quite some time. Ants have been tunneling to food sources and digging out chambers for new queens. When heavy rain drenches the nests, fire ants elevate their mounds to keep their queen, larvae and eggs above the water table.

Our technology cannot yet eliminate red imported fire ants, but we can control them in our yards. Numbers alone testify to the fact that managing the pests is an ongoing effort. Winged male and female fire ants mate in mid-air at levels up to 2,000 feet, after which the female flies as far as two to three miles before landing to build a nest.

The queen, after establishing her nest, churns out 100,000 to 300,000 eggs per year over a lifespan of six to seven years. In time, hundreds of thousands of worker ants and multiple queens may inhabit a single nest. Worker ants travel more than 100 feet in every direction from the nest to forage for food. That means a red fire ant may bite you within a 200-foot diameter of one nest.

Fire ants are a stinging insect that belongs to the same insect order as bees and wasps. Their venom contains a high concentration of poisons. They attack when their mound is disturbed, or when anyone or anything is in their way. The ants are a hazard to adults, children, pets and small wildlife.

The ants are omnivores. They eat anything from vegetation to other insects, lizards, toads and nestlings of birds that roost on the ground, in shrubbery and in low trees. They can be damaging ecologically when they infest an area. Bird lovers will be interested to know that vulnerable birds include bluebirds and quail.

Home-made alternatives to pesticides don’t work against fire ants. The most successful way to treat fire ants is with a two-step process. First, using a broadcast spreader, apply a bait formulation over your entire yard. The lawn must be dry, with no irrigation and no rain forecast for 48 hours.

By covering the entire lawn the bait reaches areas where ants forage, where mounds are visible and where they are not yet noticeable. Follow up in seven to 10 days with a mound treatment. Apply this two-part treatment in fall between August and October and in spring when mound begin to surface. Expect about 95 percent control.

Pesticide manufacturers provide easy to read packaging that informs with bold lettering whether product is formulated for bait or contact use, and mound or yard treatment. The information on packaging explains how and when to use the product for best results and user safety. Read the packaging and follow instructions.

Tips to maximize success with bait treatment

▪ Apply bait when ants are foraging—typically in late afternoon or evening when ground temperature is 70 to 95 degrees. If you are not sure ants are foraging, gently place a couple of potato chips or a small amount of bait on their mound. If they are foraging they will be all over the bait in 45 minutes.

▪ Use fresh bait. Manufacturers use soy bean oil as a carrier for their active ingredients. If the oil is rancid the ants will not pick it up.

▪ Bait must be applied to a dry lawn. Allow 24 to 48 hours before irrigation or rain is predicted.

Some baits can be used both on the lawn and in the garden around food crops. They contain active ingredients spinosad and pyriproxyfen. Spinosad is a natural metabolite produced by a soil microorganism that affects the ant’s nervous system. Pyriproxyfen is an insect growth regulator that reduces the production of viable eggs.

The toxicity of baits with active ingredients spinosad and pyriproxyfen is low to humans and non target animals. To learn more about these baits Google Clemson hgic 1263 Controlling Fire Ants in the Vegetable Garden.

Reach Debbie Menchek, a Clemson Master Gardener, at dmgha3@aol.com.

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