Recent rains have increased fire ant activity in the region. While there is no way to rid a location of fire ants permanently, there are many products available for managing them. Options include drenches, granules and baits. Drenches and granules give the quickest results, but baits provide the most effective control in the long run.
Ant control products
Drench, granule, and bait fire ant control products are available with organic as well as synthetic active ingredients, though products containing organic ingredients are more difficult to find. Most fire ant control products are labeled to use in lawns, with fewer products labeled for vegetable gardens. Check product labeling before use to make sure the product you have can be applied where you need it and for safety information regarding people, pets, and wildlife.
Drenches are mixed with water and poured onto a mound. They provide quick knock down of the mound but rarely kill all of the ants and new mounds usually pop up in the treated area within a few days. Drenches are useful when a mound needs to be quickly neutralized, but not for treating a large area. Most drench products contain synthetic insecticides like bifenthrin or permethrin. The Safer brand of products offers an organic drench with the active ingredient D-limonene, but this may be difficult to find locally.
Granules are sprinkled around a mound or broadcast over the yard. Ants are killed when they come in contact with the pesticide. Granules usually do a better job of killing more ants than drenches but rarely get them all. Most granular products contain either bifenthrin, permethrin, or a similar synthetic insecticide.
Baits are best
Baits are insecticides designed to fool pests into thinking they are food. When applied correctly, baits are the most effective, long lasting, and environmentally friendly method of fire ant control available. Baits can be applied around individual ant mounds or broadcast over a large area. Broadcasting is recommended when there are more than five mounds visible per quarter acre or over 20 mounds per acre. When applied correctly, broadcasted baits only need to be put out once or twice a year to provide excellent control of fire ants.
Baits should be applied when fire ants are actively foraging for food. During summer, ants forage most prolifically in the cooler hours of early morning and late evening. For best results apply baits in the morning after the dew has dried on a day when rain or irrigation is not expected for at least 24 hours. Always use fresh baits since the soybean oil used in baits can spoil over time. Read the label directions of any product you are thinking about using to find out what rate it should be applied and how it should be spread.
The most commonly available bait contains the synthetic insecticide hydramethylnon and is sold as Amdro Fire Ant Bait. If you prefer to use organic products, look for baits that contain spinosad as the active ingredient. Brand names of baits that contain spinosad include Ferti-lome Come and Get It, Green Light Fire Ant Control with Conserve, and Safer Fire Ant Bait. All of these products begin killing ants within a few weeks of application, though their full effectiveness is not realized for several weeks.
Some newer products, like Amdro Fire Strike and Extinguish Plus, contain both the synthetic insecticide hydramethylnon, as well as an insect growth regulator. Insect growth regulators work differently than chemical insecticides, by preventing insects from developing rather than killing them immediately.
Insect growth regulators, which include (S)-methoprene and abamectin, are extremely safe and are one of the few types of ant control products that can be used in agricultural lands, including vegetable gardens and pastures. They are very effective in the long term, but take three to four months to reduce ant populations. Since brand names change constantly, be sure to check the active ingredient listings before you purchase any pesticide to make sure you are getting the product you want.
Please Note: Any recommendations of brand names or listing of commercial products in this article are included solely as a convenience to the reader and do not imply endorsement by NC Cooperative Extension nor discrimination against similar products. Before applying any chemical, always obtain current information about its use and read the product label carefully.
To find out more about managing fire ants visit extension.org/fire_ants or contact your local Extension office. Visit ces.ncsu.edu to locate your local Extension office or post your questions to be answered online through the ‘Ask an Expert’ link.
Charlotte D. Glen is the horticulture agent with the Pender County Cooperative Extension of NC State University, College of Agriculture & Life Sciences. She can be reached via e-mail at Charlotte_Glen@ncsu.edu.