Extração e identificação dos componentes do feromônio sexual de broca dos frutos da pinha e da graviola, Cerconota anonella (Spp., 1830)(Lepidoptera: Oecophoridae)

Abstract

This study aimed the extraction, identification and synthesis of the sex pheromone components of Cerconota anonella (Sepp.) (Lepidoptera: Oecophoridae) and to evaluate their efficiency on tests conducted under laboratory and field conditions. The ultimate goal of this research is to use the sex pheromone to control infestations of C. anonella based on the integrated pest management program for species of Annonaceae. Initially, to choose the best solvent for extraction of pheromone components, experiments were carried out using hexane and dichloromethane to wash the abdominal gland of 2-3 days-old C. anonella calling females. These extracts were used on bioassays performed under laboratory conditions using 2-3 days-old co-specific males in a room programmed to operate with an inverted photoperiod (12: 12 h). The males exhibited a strong response to the hexane extract of virgin females and this result was also seen on field tests, where it was observed that the number of males captured on traps baited with hexane extract of virgin females did not significant differ from the traps containing live calling virgin females. The chemical identification of components present in hexane extract of C. anonella was performed by Gas Chromatography coupled to Mass Spectrometry. These analyses showed four major compounds, namely: (OOI), (OA) (OM) and (OAL) among some other components. The first two compounds were obtained commercially and the other two were synthesized in the laboratory using OOI as starting material. The olefinic derivatives of these compounds were also obtained and used on bioassays. Individual synthetic components, ternary and quartenary mixtures of these compounds were submitted to laboratory bioassays using C. anonella virgin males, as follow: individual compounds labeled as (OM), (OAL), (OOl) and (OA); quaternary mixture of saturated compounds [1 (OM): 3 (OAL): 5 (OOI): 5 (OA)], ternary mixture of unsaturated compounds [1 (OMI) 3 (OALI): 5 (OOII)], ternary mixture of saturated compounds [1(OM):3 (OAL):5(OOI)], empty filter paper disc and filter paper disc impregnated with hexane. Individual compounds and mixtures were tested in two concentrations, as such: 0, 1 and 1,0 mg/ml, respectively. On laboratory bioassays, it was observed if changes in concentration and the degree of saturation of the tested compounds within the mixtures would affect the number of attracted males. Except for the individual compounds, all tested mixtures were attractive to males. Results from field tests revealed that, among the synthetic mixtures tested, the traps containing the saturated ternary mixture [1 (OM) 3 (OAL): 5 (OOI)] in a concentration of 1 mg / ml captured as many males as the trap containing live virgin females. No field tests were conducted with mixtures of unsaturated synthetic compounds. From these results, it is safe to conclude that the compounds reported on this study are indeed sex pheromone components of C. anonella. In addition, this study also shows that Solid Phase Microextraction (MEFS) is a reliable technique for extraction of C. anonella sex pheromone components as well as the dynamic headspace technique (aeration).