Development of natural attractants to control the Mediterranean fruit fly <i>Ceratitis capitata</i> (Tephritidae) in Gafsa oasis, Tunisia

Abstract

A natural attractant for Ceratitis capitata developed by microencapsulation by coacervation complex with gelatin and gum arabic of the essential oil of Ruta graveolens was evaluated. Essential oil composition was analyzed by Gas Chromatography Mass Spectrometry (GC/MS). Microencapsulation efficacy was evaluated by determination of the encapsulation yield (%), encapsulation efficiency (%), optical microscopy, Fourier transform infrared spectroscopy (FTIR) and release kinetics (%). Repellent/attractant and contact toxicity tests of crude and encapsulated Ruta graveolens oil were assessed under laboratory and field conditions. GC-MS analysis indicated that 2-nonanone (36.31%) and 2-undecanone (35.92%) were the dominant compounds. Encapsulation yield was 77.06% and encapsulation efficiency was 73.33%. Optical microscopy pictures revealed spherical form particles. Results exhibited the attractant potential of crude oil (class III: moderately attractant) and that encapsulated oil accomplished better attractant performance (class IV: attractant). The encapsulated oil was also toxic to Medfly adults. Results further showed that both Ceratrap® and oil capsules were attractant under field conditions. This work supports the practice of encapsulated essential oil as natural attractant for Medfly management.