Are landscaping mulches repellent to red imported fire ants Solenopsis invicta Buren (Hymenoptera: Formicidae)?

Anecdotal observations suggest that decorative mulches around ornamental plantings near homes and public areas may reduce activity of the red imported fire ant (Solenopsis invicta Buren) or may be repellent to colonies. Finely ground, commercially available mulches, both dry and moist, of red cedar, pine bark, red cypress, cypress, and hardwood bark were tested for repellency against laboratory and field colonies of S. invicta. Red cedar mulch showed some repellency; however, in general, small quantities of the mulches were not deterrent to S. invicta as measured by recruitment of foragers to food sources.