Fire Ant Biology and Pest Control
Fire ants are a nuisance and a painful pest to anyone unlucky enough to live in their stomping grounds. It is unlikely we will eradicate these pests any time soon, but we can remove the problem associated with them by good integrated pest management (IPM) practices. This involves reducing their populations to tolerable levels by using safe and effective methods of control.
This article will deal with three ant elimination methods: baiting,
mound drenching and broadcasting
of contact pesticides. In many cases, these methods can be used together in
a year-round program.
This program may be implemented 1 to 3 times per year, varying with severity of ant infestation.
When treating mounds with any contact insecticide or professional bait, do not disturb mounds before treating. If you do, the colony will immediately take the queen or queens to safety, either deep down in the mound or move them laterally to establish satellite mounds. This stressing of the colony causes more problems than anyone can imagine.
Generally, it takes 1 to 2 gallons of mixed pesticide solution to drench a fire ant mound effectively. A mid-morning drench treatment is best when the sun starts warming up the colony. There are many insecticides that may be used for mound drenching, but we have the seen the best results with the following active ingredients: Bifenthrin (Talstar liquid concentrate, Talstar granules,) Cypermethrin (Cynoff EC, Cynoff WP, Demon EC, Demon WP, Cypermethrin 4 ounce) or Permethrin (Permethrin Pro, Dragnet, Flee.) These materials are all in the synthetic pyrethrin class of chemicals. Synthetics are far more photostable than common organophosphates (Durban, Diazinon, Malathion, Acephate) which can lose their effectiveness in as little as three hours of sunlight. Mounds properly drenched with synthetic pesticides can kill returning or foraging ants for 30 days or more! As an added benefit, synthetic pyrethroids are safer for humans and domestic animals as well as the environment, when used as directed by the label. The best example is Talstar, whose molecules actually bond to soil particles. This means that the material stays where you apply it and does not leach out into undesirable locations.Top of Page
Permethrin Pro and Talstar (liquid and granular) give the best long term control when broadcasting large areas with a hose-end sprayer. Permethrin Pro calls for 1 ounce of concentrate per 1,000 square feet. Talstar uses only 1/8 to 1/4 ounce per thousand. If granular pesticides are preferred, use Talstar Granules or DeltaGard granules. Although it is used at very low rates, Talstar has given us the longest control; many customers state that no ants re-enter a treated area for as long as three months!
The use of professional ant baits is a very thorough method of control, slowly killing the entire colony. Baits work best when used in the spring and early summer. When the weather gets hot and dry, baits are generally ineffective for fire ant control. However, fire ant baiting has two drawbacks: cost and length of control time. For instance, baiting an entire area will kill the existing ant colonies but will not always control new ant colonies invading from nearby areas that were not baited properly. Also, most people with fire ant problems live on very large lots -- 2 acres or better. This involves a great deal of bait at a premium price.
The most successful baiting practice for fire ant control on turf is to use granular baits such as Ascend or Maxforce Granular (or Extinguish Fire Ant Bait when baiting graze lands) in the early spring followed by soil drenches 4 to 6 weeks later if needed. Broadcast granular bait applications are most effective; however, it may take 4 to 6 weeks to give control. Early spring application is ideal because it controls recently developed queens before they leave on their nuptial flights and establish new colonies. Killing the queens is the only way to eliminate fire ant colonies. Follow-up granular bait applications usually are necessary in mid-summer and another one in the fall.
Apply baits when the ground is dry and when ground temperatures are between 70 and 90 °F with no forecast of rain. Apply baits around the base of mounds and also broadcast the entire areas where ants are seen foraging.. Baits are picked up by foraging ants looking for food. The ants take the bait back to the ant colony; it passes through the food chain and is fed to the queen ants. Granular bait recommendations are listed below.
In summer and fall, apply bait in the afternoon when temperatures are
cooler because baits may rapidly degrade on hot, sunny days. By the time ants
pick up the bait, the heat may have broken down the active ingredient, losing