Antifeedant Activities of Organic Fractions from Cestrum parqui Leaves on the Red-Haired Bark Beetle Hylurgus ligniperda

Abstract

Hylurgus ligniperda is one of the most important quarantine forest insects associated to pine (Pinus radiate D. Don) logs exported from Chile. Methyl bromide fumigation has been the prominent control method. As the use of this synthetic insecticide leads to serious environmental problems, research to find alternative treatments is urgently needed for the Chilean forestry sector. Hence, plant secondary metabolites have been considered as an alternative for its control. Therefore, the objective of this work was to assess the feeding behavior of H. ligniperda through the artificial diet supplemented with organic fractions obtained from Cestrum parqui leaves. Organic extracts were obtained using a Soxhlet extraction. Non-choice tests were developed for testing the antifeedant activity shown by the organic fractions on adults, and 5th and 6th instar larvae of H. ligniperda. All the extracts tested elicited a decrease in the weight of unsexed H. ligniperda adults, and the effects were dose-dependent. Male beetle weight gain was reduced strongly by chloroform extracts and ethyl acetate elicited a weight increase of female and from the fifth and sixth instar larvae weight. Saponin extract elicited a reduction of the weight in male and female. Finally, the weight of both instar larvae was reduced by chloroform and saponin extract. C. parqui leaf extracts show a great potential for being used for controlling H. ligniperda and thus to diminish the use of harmful synthetic pesticide.