MANAGEMENT OF THE STINGING ANT MYRMICA RUBRA, USING A BAITED GRANULAR FORMULATION OF HYDRAMETHYLNON, 1997

Myrmica rubra is an introduced ant that presently occurs on Mount Desert Island, ME, in the vicinity of Acadia National Park, where its painful sting has created problems for residents. Field trials to manage this species with Amdro were conducted at two sites where treated and untreated plots were established: a linear site, with 3.05 by 22.86 m (10 by 75 ft) treated and untreated plots separated by a 3.05 by 30.48-m (10 by 100-ft) buffer plot, and a rectangular site with 18.29 by 27.43-m (60 by 90-ft) treated and untreated plots separated by a 30.48 by 27.43-m (100 by 90-ft) buffer plot. Traps were set at 4.57-m (15-ft) intervals through the middle of the treated, buffer, and untreated plots (total of 16 traps at the linear site and 36 traps at the rectangular site). Ants were trapped using Tic-Tac containers baited with a small piece of cotton soaked with a 50:50 sucrose:water solution set daily for » 2 h between 0800 and 1100 hours. Trapping started on 11 Aug 1997, and a granular ant bait with 0.73% hydramethylnon (Amdro) was applied at a rate of 0.15 kg (1/3 lb) per 929.03 m2 (10,000 ft2) using a seed broadcaster on 18 Aug. Daily trapping continued posttreatment until 26 Sep. Percent control was calculated using a modified Abbott's formula: % control = 100 [(mean in treated area after treatment/mean before)/(mean in untreated area after treatment/mean before) 100]. Changes in ant numbers from the week before to the week after treatment were compared between treated, buffer, and untreated sites by ANOVA using SYSTAT, subprogram MGLH, with data transformed by ln(x+1) to minimize trends in plots of residuals versus estimates.