Identification
Large (5–10 mm), heavy-bodied, usually red to reddish-brown, with a 'psammophore', a fringe of long hairs on the underside of the head used to carry sand. Nest is a broad cleared circle of bare ground 3–10 ft across with a central mound and entry crater; foraging trails radiate outward in straight lines.
Biology & Colony Structure
Long-lived colonies (15–30+ years for the queen) with 10,000–12,000 workers. Diurnal foragers active in heat that excludes most other ants. Mating flights occur on summer afternoons after monsoon rain.
Pest Status & Significance
Sting hazard to children, pets, livestock, and horses near corrals and barns. Cleared discs are unsightly in maintained turf. Ecologically vital, red harvester (P. barbatus) is the primary prey of the Texas horned lizard, a species of conservation concern, and broad-area suppression of harvester ants has contributed to horned lizard declines. Treat only where there is a real human or livestock conflict.
Harvester Ant Control Strategy
Spot-treat individual problem mounds rather than broadcasting. Acephate dust on the disc gives fast control. Avoid blanket treatment of pastures or rangeland.
Recommended Baits & Active Ingredients
Product names are representative of the active-ingredient class and intended for licensed PMPs. Always read and follow the label; rates, sites, and restrictions vary by formulation and state registration.
| Product | Active | Form | Use |
|---|---|---|---|
| Amdro Pro | Hydramethylnon 0.73% | Granular | 1 tbsp applied 2 ft from individual mound entrances; accepted as 'seeds.' |
| Orthene Fire Ant Killer | Acephate 75% SP | Dust | Dust the cleared disc and central crater; fastest knockdown. |
| Sevin SL | Carbaryl 43% | Drench | Mound drench in 1–2 gal water; effective but broad-spectrum. |