Testing the Temporal Limits of Lures and Toxicants for Trapping Fruit Flies (Diptera: Tephritidae): Additional Weathering Studies of Solid Bactrocera and Zeugodacus Male Lures and Associated Insecticidal Strips

Abstract

Detection of pestiferous fruit flies (Diptera: Tephritidae) relies largely on traps baited with male-specific attractants. Surveillance programs in Florida and California use liquid methyl eugenol (ME, attractive to males of Bactrocera dorsalis (Hendel)) and liquid cue-lure (CL, attractive to males of Zeugodacus cucurbitae (Coquillett)) mixed with the toxicant naled to bait detection traps. However, this practice requires considerable time and may subject personnel to health risks. Recent work indicates that solid male lures deployed with a separate insecticidal (DDVP) strip are as effective as the standard liquid formulations. Specifically, solid ME and CL dispensers and DDVP strips were weathered for 6 or 12 weeks under summer conditions in AZ and FL and subsequently field tested in Hawaii. Results showed that (i) solid ME dispensers weathered for 6 weeks, but not 12 weeks, were as attractive as fresh liquid ME, and (ii) solid CL dispensers and the insecticidal strips were as effective as fresh liquid formulation for at least 12 weeks. The present study expands upon these earlier findings and addresses two specific questions: Could solid ME dispensers be deployed for 8 or 10 weeks without loss of effectiveness? Could solid CL dispensers and insecticidal strips be deployed for intervals even longer than 12 weeks? Adopting the same protocol noted above, the present study indicates that effective field longevities are 10 weeks for solid ME dispensers, at least 20 weeks for solid CL dispensers, and 12 weeks for the DDVP strips. Comparisons are drawn with related studies, and implications for tephritid surveillance programs are discussed.