INFLUENCE OF ENDOGENOUS FACTORS ON THE ELECTROPHYSILOGICAL AND BEHAVIORAL PERCEPTION OF HOST PLANT VOLATILES BY GRAPHOLITA MOLESTA (BUSCK) (LEPIDOPTERA: TORTRICIDAE)

ABSTRACT

The oriental fruit moth, Grapholita molesta (Lep.: Tortricidae), stands out as one of the most important pests in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. The present work was aimed to study the influence of the host plant volatiles and the interaction of these with synthetic sex pheromone in the chemical perception and in the chemotactic behavior (olfatometry) of this species. The electroantennographic perception of both sexes of G. molesta that had been fed or not fed extracts of shoots and ripe and unripe fruits of apple (Malus domestica, Gala cv.) and peach (Prunus persicae, Chiripá cv.) trees was observed. The endogenous factors evaluated were the age, the mating status and the feeding in response to peach-tree shoots extract (PTSE). The effect of the extract interaction with pheromone was evaluated in males. The electrophysiological perception of the plant volatiles by males and females did not vary with feeding status. For both sexes, PTSE elicited the stronger electrophysiological responses. The chemotactical behavior in the presence of PTSE showed a tendency to be higher in mated females. An additive effect was noticed between the sexual attractant and the PTSE in the males’ electrophysiological perception. However, the behavioral results did not corroborate with those obtained in the electroantennography. The results obtained aid in the understanding of the interference of endogenous factors in the chemical communication among G. molest and host plants, improving the adaptation and reliability of infochemicals in the behavioral control of the oriental fruit moth.

KEY WORDS
Eletroantennography; olfactometry; oriental fruit moth; behavioral control; pheromone