Estudo feromonal, perfil cuticular e preferência alimentar de Thyrinteina arnobia (Stoll, 1782) (lepidoptera geometridae) em diferentes hospedeiros

Abstract

With the consolidation of eucalyptus crop, the attack of phytophagous insects has acquired relevant economic importance, which may generate significant yield losses. Among them, the eucalyptus brown caterpillar, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae), stands out, considered as the main defoliating pest of Eucalyptus spp. in the country. Thus, the present study aimed to verify the processes involved in host interaction, based on the characterization of the cuticular profile and food preference of T. arnobia on different native and exotic hosts, besides the prospection for pheromone substances from T. arnobia through isolation and structural identification, in order to contribute as a basic component for the development of Forest Integrated Pest Management (Forest IPM). On non-choice food consumption tests, it was observed a greater food comsumption of the VE 41 clone and the native host guava (Psidium guajava L.). The evaluation of food consumption with chance of choosing using clones of E. urograndis and guava showed no significant difference, which may indicate T. arnobia adaptation to both its native and exotic host. In tests using E. urograndis clones, the I 144 clone showed a tendency towards less food preference, being consumed only after 48 hours. In cuticular chemical profile, comparing the Kovats Index (IK) of branches and caterpillars from guava and eucalyptus, it was possible to observe a total of 9 compounds in common between guava branches and T. arnobia caterpillars and only 1 compound in common when compared to the chemical profile of E. urograndis branches. For the pheromone study, the cuticular extracts of the wings and legs of females and males of T. arnobia were not shown to be biologically active against male antennae. In the extracts of T. arnobia female abdominal glands, 12 chemical compounds were verified in gas chromatography coupled to mass spectrometry (GC-MS), with 9,12-octadecadienol chloride and hexadecanoic acid (palmitic acid) being the major components, obtaining a significative response against male antennas via electroantenography "puff" method. The results obtained are pioneering for the development of behavioral control strategies in Forest Integrated Pest Management (Forest IPM) in the state of Alagoas.