Antifeeding and Insecticidal Activity of Ailanthus altissima and Morus alba Extracts Against Gipsy Moth (Lymantria dispar (L.), Lepidoptera, Lymantridae) Larvae Under Laboratory Conditions

Abstract

Gypsy moth (Lymantria dispar L.) is one of most important defoliating pests of deciduous trees. Due to increased environmental demands, the use of plant-based preparations is gaining in importance as a control option for this pest in forestry, agriculture and horticulture. The aim of this study was to evaluate antifeeding and insecticidal activity of 0.5, 1 and 2% extracts of Ailanthus altissima bark and leaves, and Morus alba leaves, against L. dispar larvae under laboratory conditions. Antioxidant capacity of plant extracts was determined, as well as the content of phenolic compounds by spectrophotometric and HPLC-DAD methods. Antifeeding and insecticidal effects were tested in a “no-choice” test. The highest content of all bioactive phenolic compounds was in A. altissima bark and M. alba leaf extracts. The lowest leaf consumption after 24 and 48 h was in A. аltissima bark (5.03, 9.48%, respectively) and M. alba leaf (1.44, 2.97%, respectively) extracts. A. altissima bark and M. alba leaf extracts expressed strong antifeeding activity. After 24 h, all extracts expressed slight insecticidal effect (1.25-17.50% of mortality). The mortality increased after 48 h in treatments with A. altissima bark extract, at all applied concentrations (40.0-58.9%) and M. alba leaves at 1 and 2% concentrations (30.0-58.9%). Our results indicate that extracts of A. altissima bark and M. alba leaves may act as effective low-cost natural protectants able to control the presence of gypsy moth in ecosystems. Extracts of A. altissima bark and M. alba leaves expressed strong antifeeding activity and significant insecticidal effect on gypsy moth larvae, at all applied concentrations.