tert-Pentyl 4 (and 5)-chloro-trans-2-methylcyclohexanecarboxylate, a Highly Effective and Persistent Male Specific Attractant for the Mediterranean Fruit Fly (Diptera: Tephritidae)²

The attraction of male Ceratitis capitata (Wiedemann) to tert-pentyl 4(and 5)-chloro-trans-2-methylcyclohexanecarboxylate (or pentamedlure) was compared to its attraction to trimedlure to establish the suitability of pentamedlure as a possible alternate for trimedlure in applications that use a cotton dental-roll wick dispenser. Results from field tests with released sterile C. capitata showed that pentamedlure, applied to cotton dental roll wicks, was not only comparable to trimedlure in attractiveness but was more persistent. Batch to batch variations in isomer distribution of pentamedlure appeared to have little effect on attraction. Dose-response data showed that pentamedlure, applied at 0.02 and 0.16 ml/wick, initially caught more flies than trimedlure at comparable doses. Moreover, initial catches for pentamedlure for most dosages tested exceeded, but not significantly, initial catches for trimedlure despite a much higher load (2 ml/wick). Trimedlure initial catches within a natural population of wild C. capitata were significantly higher than pentamedlure catches at a comparable dosage (0.2 ml lure/wick). However, pentamedlure-treated wicks were 2 to 3 times more persistent than wicks treated with trimedlure.