Detection of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is highly reliant on traps loaded with trimedlure (TML), a male-specific attractant. The successful application of attractants requires that constituents are placed in a suitable dispensing system to reduce volatilization and increase the effective field longevity of the attractant. A series of trials were conducted in different fruit orchards to test 1) the efficiency of a polyethylene-matrix plug in regulating the emission rate of TML 2) and the lifetime attractiveness of the plug compared to the cotton wick dispenser. Cotton dispensers containing the recommended dose of TML (0.75 cm³) and with a double dose (1.5 cm³) remained active for 6 and 8 wk, respectively. The increase in TML dose from 0.75 cm³ to 1.5 cm³ led to an increase in the longevity of the cotton dispenser, but there was no significant difference between the doses in biological activity. In all trials, TML-polyethylene matrix dispensers were more efficient under field conditions as they attracted more males for up to 12 wk and prolonged the release of TML more than the cotton wick dispensers. The TML-loaded polyethylene matrix dispensers might be useful in 1) minimizing the losses of the liquid TML from cotton wicks, 2) avoiding the damage that occurs when using other dispensers, 3) prolonging the TML lifetime in the field through regulating its release rates, 4) potentially minimizing the adverse effect of high temperatures on release rate, and, finally, 5) minimizing the costs of using large amounts of expensive TML solutions.