TOXICITY OF A BORIC ACID-SUCROSE WATER BAIT TO SOLENOPSIS-INVICTA (HYMENOPTERA, FORMICIDAE)

Boric acid-sucrose water baits were evaluated in the laboratory for to xicity, and efficacy against the red imported fire ant, Solenopsis inv icta Buren. Over the dosage range from 0.02 to 1.0% boric acid, LC(50) s (95% CL) ranged from 1.27% (1.05-3.88%) at 3 d to 0.11% (0.09-0.13%) at 8 d. Amount of bait consumed was related inversely to the concentr ation of active ingredient. High concentrations of boric acid bait (5% ) were consumed at a lower rate than the control (10% sucrose water). In large fire ant colonies exposed continuously to 4 concentrations (0 .25, 0.5, 0.75, 1.0%) of boric acid bait, workers and brood were reduc ed by 90% at 6 wk. Therefore, low concentrations of boric acid are nec essary for delayed toxicity and reduced repellency.