Design, Effectiveness, and Performance Criteria of Dispenser Formulations of Trimedlure, an Attractant of the Mediterranean Fruit Fly (Diptera: Tephritidae)

Abstract

Controlled-release dispensers of trimedlure (TML), a synthetic attractant of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were evaluated in seven aging tests in natural and released populations. Insect captures and laboratory-measured release rates and residual contents showed that the cotton wick dispensers, which were formerly used for 2 g liquid TML (density = 1.0 g/ml), were generally ineffective after 2-4 wk of field exposure; a 4-g dose of TML increased the longevity, but not the initial biological activity of the cotton wick. Two controlled-release formulations, a polymeric plug (70% by weight TML) and a plastic laminate, extended the effective lifetime of 2 g TML to about 8 wk. A polymeric plug with 4 g TML further extended the duration of effectiveness to 12 wk or longer. Laboratory and field data suggested definitive values for relative insect capture, release rate, and residual trimedlure content, which have been used as performance criteria in the purchase of trimedlure dispensers.