Chemical composition of Vitex agnus-castus L. (Verbenaceae) essential oil and its larvicidal effectiveness on Thaumetopoea pityocampa (Denis & Schiffermuller, 1775) (Lepidoptera: Notodontidae) larvae

In this study, the chemical composition of the essential oil obtained from chaste tree (Vitex agnus-castus L.) (Verbenaceae) was analyzed by gas chromatography-mass spectrometry (GC-MS) and its larvicidal effectiveness at 250, 500 and 1000 mu L/L, and 24, 48, 72 and 96 h against the five instars of the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermuller, 1775) (Lepidoptera: Notodontidae) investigated. The study was conducted at Mugla Sitki Kocman University (Fethiye A.S.M.K. Vocational High School) under laboratory conditions (25 +/- 2 degrees C, 65 +/- 5% RH and 14:10 h L:D photoperiod) in 2015-2017. Each larvicidal effectiveness test was repeated three times. beta-caryophyllene (16.8%), germacrene D (14.7%), 1,8-cineole (14.5%) and.-gurjunene (11.8%) were identified as main compounds of the essential oil. Ninety-six h after treatment, the essential oil caused between 13.3 and 96.6% mortality. The highest mortality at 250, 500 and 1000 mu L/L doses were 70.0% for L1, 80.0% for L3 and 96.6% for L1, L3 and L4 instars after 96 h, respectively. It was concluded that the V. agnus-castus essential oil has potential as an alternative for control of T. pityocampa larvae.