Extração e identificação de compostos voláteis de plantas de Annona muricate e Annona squamosa, em diferentes estágios de maturação, atraentes para a broca dos frutos Cerconota anonella

Abstract

Custard apple (Annona squamosa) and soursop (Annona muricata) stand out in fruit farming in several parts of the world and have great commercial acceptance. The production of these fruits constitutes an important factor of economic impact; however, one of the main obstacles to the economic exploitation of these fruit trees is the existence of a complex of pests that attack these cultures, such as the fruit borer (Cerconota anonella), which is the main pest causing this problem. Thus, this study aimed to carry out a survey on patents referring to Annona semiochemicals used in pest control, analyze the molecular biology of C. anonella and identify the sensilla which binds to odorant molecules in the female antennae of this insect species, as well as to extract and identify the volatile compounds of A. muricata and A. squamosa plants at different maturation stages (vegetative, flowering and fruiting) that attract the fruit borer insect. Infested soursops were collected from orchards in the estate of Coruripe, Alagoas State, Brazil, to obtain adults. The volatile compounds emitted by the studied plants were collected through the dynamic headspace technique. DNA extraction, PCR (Polymerase Chain Reaction), sequencing, SEM, GC-MS and GC-EAD were also performed. The data from bioassays were subjected to statistical analysis using the Wilcoxon test (p<0.05). A total of 201 patents were found on the PATENTINSPIRATION database where the term “Annona” was used. Brazil ranks eleventh with five patents. The molecular biology analysis confirmed the identification of the species and the SEM analysis identified a diversity of sensilla in the antennae of the C. anonella female insects (basiconic, chaetic trichoid, among others). The bioassays revealed that the control treatment did not elicit any attraction on females when compared to all treatments tested. Females were attracted to plants even before fruiting, including the flowering stage. However, the fruiting was the preferred stage. There were no significant differences when comparing the extracts of plants at the preferred stages of maturation. Terpenes, esters, alcohols, ketones, aldehydes were the classes of compounds identified by GC-MS. Four bioactive compounds, namely: β-mycrene, β-ocimene, methyl benzoate and linalool, present in the fruiting stage of A. squamosa were identified. The synergistic effect for the formulation of the mixture containing the extract of A. squamosa in the fruiting stage with the extract of sex pheromone glands of conspecific females was proven.This finding suggests that the pest may be in the field before fruiting and that chemoreceptors play a fundamental role in the choice of the molecules by C. anonella females. the patent review showed that information about the chemical ecology of species of the genus Cerconota, particularly C. anonella, is still incipient. Thus, the present work presents a more accurate study about the heterospecific and homospecific interactions between adults of C. anonella and the plants of A. squamosa.