Trapping Pestiferous Fruit Flies (Diptera: Tephritidae): Additional Studies on the Performance of Solid Bactrocera Male Lures and Separate Insecticidal Strips Relative to Standard Liquid Lures

Abstract

Detection of pestiferous Bactrocera fruit flies relies largely on traps baited with male-specific attractants. Surveillance programs in Florida and Cali- fornia use liquid methyl eugenol (ME, attractive to males of B. dorsalis (Hendel)) and liquid cue-lure (CL, attractive to males of B. cucurbitae (Coquillett)) mixed with the toxicant naled to bait traps. However, the application of the liquids requires considerable time and may subject personnel to health risks from inadvertent exposure to the lure and the insecticide. Recent studies have shown that solid dispensers containing a toxicant perform as well or better than liquid lures, but the combination of lure and toxicant in the same solid dispenser faces registration problems. Fewer studies have assessed the efficacy of solid, and separate, lures and toxicants, but existing data are promising. Here, we present the results of two independent studies that further assess the effectiveness of solid ME and CL lures and their associated, but separate, insecticidal strips. The first study, conducted exclusively in Hawaii over a 12 week period, found that captures of B. dorsalis or B. cucurbitae males were similar between traps baited with the standard liquid formulation and traps baited with solid lure dispensers and either 1 or 2 insecti- cidal strips. In the second study, solid lure dispensers and associated insecticide strips were weathered for 6 or 12 weeks under summer conditions in Arizona and Florida, where high temperatures were presumed to result in high volatility and thus provide a rigorous test of field longevity. Aged materials were shipped to Hawaii for testing against fresh (non-weathered) lures and insecticidal strips in wild populations. The results were fairly consistent between Arizona- and Florida- weathered devices and indicated that (i) solid ME dispensers were effective for 6 weeks but lost significant attractancy at 12 weeks and (ii) CL solid lures and the insecticidal strips were effective for at least 12 weeks. Collectively, these findings provide additional evidence that surveillance programs could switch to solid lures and toxicants and maintain a high level of detection sensitivity