Ocorrência de lepidópteros em Corymbia spp. e Eucalyptus spp. e estudo de semioquímicos para o manejo integrado de Thyrinteina arnobia (STOLL, 1782) (lepidoptera: geometridae) em Alagoas

Abstract

With the consolidation of eucalyptus cultivation in Brazil, defoliator lepidopterans began to cause damage to Eucalyptus spp. and Corymbia spp. plantations, especially during population outbreaks. The defoliator species commonly reported are Thyrinteina arnobia (Stoll, 1782), Eupseudosoma involuta (Sepp, 1952) and Sarsina violascens (Herrich-Schaeffer, 1856), and T. arnobia is considered the main eucalyptus defoliator caterpillar in the country. In this sense, knowing the population dynamics makes it easier to determine the most common species and the main population peaks, facilitating the establishment of control measures. In the case of T. arnobia, chemical ecology is now required in the development of Integrated Forest Pest Management (IPM) strategies, mainly using semiochemicals (pheromones).The aforementioned work was divided into two chapters, with the objective of recording the occurrence of defoliating caterpillars in forest populations of Eucalyptus spp. and Corymbia spp. in the state of Alagoas, as well as the pheromone prospecting of T. arnobia glands in forest populations of Eucalyptus spp. Initially, inspections, photographic records, and caterpillar collections were carried out in the field, specifically in eucalyptus plantations located in the municipalities of Atalaia, Marechal Deodoro, and Ibateguara, all situated in Alagoas. Subsequently, the breeding and chemical study of T. arnobia were conducted at the Agricultural and Forest Entomology Laboratory (LEAF) of the Engineering and Agricultural Sciences Campus (CECA), located in Rio Largo – AL, and at the Natural Resources Research Laboratory (LPqRN) of the Institute of Chemistry and Biotechnology (IQB), of the A.C. Simões Campus. Simões. It was possible to record caterpillars of the genus: Apatelodes spp.; Phobetron spp.; Lophocampa spp. and Eupseudosoma spp., as well as T. arnobia, in eucalyptus plantations in Alagoas. Through gas chromatography coupled with flame ionization detection (GC-FID), 7 possible compounds were identified in the glands of virgin female T. arnobia: endo-Bicyclo [2.2.1] heptan-2-ol, Methoxymethyl-benzene, Octan-3-one, 1-Isopropyl-4-methyl-1- cyclohexene, 1-Methylpiperidine, 1,2,5,7-Tetramethylnaphthalene, and Hexyl 2- hydroxybenzoate. The occurrence record carried out in this work is considered pioneering in Alagoas, allowing for the identification of the aforementioned genera of defoliating lepidopterans and the geographical distribution of these insects, in addition to serving as an informational basis for devising control strategies in the event of a population outbreak in eucalyptus plantations in the state. The pheromone study conducted on virgin females of T. arnobia revealed possible compounds, although they are different from the major components found in the literature, suggesting that the difference in chemical composition may be linked to geographical factors. The results obtained in this work, although preliminary, serve as a baseline study for Forest IPM in Alagoas.