LIQUID BORATE BAIT FOR CONTROL OF THE ARGENTINE ANT, LINEPITHEMA HUMILE, IN ORGANIC CITRUS (HYMENOPTERA: FORMICIDAE)

A liquid bait delivery system containing borate was evaluated for controlling the Argentine ant, Linepithema humile (Mayr), in an organic citrus orchard. Two concentrations of disodium octaborate tetrahydrate (1% and 0.5%) were tested in 500-mL capacity bait stations placed at the base of trees. Both concentrations significantly reduced ant activity over the 11-wk duration of the test when compared with controls. However, the 1% concentration of borate significantly reduced ant activity up to 76 m away from the treatment, whereas the 0.5% did not. Compared to ant control with contact insecticides, the bait delivery system uses less insecticide and is more target-specific, reducing environmental contamination.