title: Effects of bait age and prior protein feeding on cumulative time-dependent mortality of Anastrepha ludens (Diptera: Tephritidae) exposed to GF-120 spinosad baits.
abstract: A fruit fly bait to attract and kill adult fruit flies, GF-120, was tested in cages to determine effects of pretreatment diet and bait aging before use on cumulative mortality rates of Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae). Protein-starved and protein-fed, 9-d-old flies both experienced varying overall cumulative mortality at 4, 8, 24, and 48 h. Pretreatment diet had no significant effect on mortality. Overall mortality rates were below 10% for 4 h, 39-43% at 8 h, but mortality in all treatments increased to 89-93% by 24 h, and 99% by 48 h. In a second experiment, GF-120 baits were either freshly prepared or aged for 24 h. Subtreatments consisted of protein-fed and protein-starved flies. The 24-h-aged bait killed significantly more flies at 4 and 8 h than the freshly prepared bait. Protein-starved flies had significantly higher mortality at 4 h and marginally higher mortality at 8 h than protein-fed flies. At 24 and 48 h, there were no significant differences among treatments, and overall morality rose to 99-100% by 48 h. These results may explain differences noted in previous publications in which fruit fly mortality to GF-120 was reported as unusually low as well as reports of bait ineffectiveness for protein-fed flies. The overall impact of any initial repellency of GF-120 seems negligible as judged by overall cumulative mortality at later evaluation times.
authors.affiliation: USDA-ARS Crop Quality and Fruit Insects Research Unit, Kika de la Garza Subtropical Agricultural Research Center, 2413 E. Highway 83, Weslaco, TX 78596, USA. robert.mangan@ars.usda.gov
authors.forename: Robert L
authors.initials: RL
authors.lastname: Mangan
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004044:Dietary Proteins / Q000378:metabolism; D004338:Drug Combinations; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000633:toxicity*; D018942:Macrolides / Q000633:toxicity*; D008800:Mexico; D033621:Tephritidae / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors
chemical_list: D004044:Dietary Proteins; D004338:Drug Combinations; D007306:Insecticides; D018942:Macrolides; C415329:spinosad