• Introduction
• The Problem
• Developing a Management Plan

• Farmstead or Headquarters
• Hay Pastures
• Livestock Pastures or Rangelands
• Farm Ponds
• Orchards
• Field Crops

• Bait Basics
• Individual Mound Treatments
• More Information
• Disclaimer
• Contributors
• Print this Lesson

Hay bales on a trailer.

Fire ant mounds in hay pastures can cause equipment breakdowns when cutting machinery hits tall, hardened mounds. The ants may also consume seeds or seedlings of some forage crops. On the beneficial side, the ants also prey on other arthropod pests such as armyworms, and they reduce soil compaction by building nests and foraging tunnels. Some producers have replaced sickle-bar-type cutters with disc-type cutters to reduce equipment breakdown. Even these cutters, however, become jammed with grass and moist soil when cutting through ant mounds, resulting in a loss of time. Some producers raise the cutter, at least when approaching tall mounds, thereby losing some yield. Dull cutting blades and increased wear on machinery also cost money and lost time. Custom cutting and baling operators may charge more for their services where fire ant infestations are severe.

Infested hay is a regulated item when it is to be shipped out of quarantined areas. Field workers can be stung, particularly when handling square bales. For these reasons, some growers have shifted from producing square bales to producing round bales.

Where imported fire ants are a problem, costing more than about $15 per acre to treat, broadcasting registered bait-formulated products, such as hydramethylnon (Amdro Pro) or methoprene (Extinguish), pyriproxyfen (Esteem), or a hopper blend (see below) can reduce ant numbers and result in reduction of mound height and number. Mound treatments using registered products such as agricultural formulations of carbaryl (Sevin) or a fast-acting bait such as hydramethylnon should be reserved only for nuisance mounds.

Shallow disking and dragging a heavy object such as a railroad tie will reduce mound height for several weeks to months but used alone will not reduce ant or mound numbers. In areas infested with multiple queen colonies, dragging may cause the colonies to split into more but smaller colonies. Furthermore, if ants are not eliminated using an insecticide, reduced mound height will be temporary. Tall mounds can persist even after ant colonies are eliminated where grasses and other vegetation have grown into mounds.