Toxicities of different essential oils to Tetranychus urticae Koch, 1836 (Acari: Tetranychidae) and Acanthoscelides obtectus (Say, 1831) (Coleoptera: Bruchidae) adults

Abstract

In this study, the toxicities of plant essential oils of Artemisia absinthium L., Seriphidium santonicum (L.) Sojak, Seriphidium spicigerum (K. Koch) Poljakov and Achillea santolinoides Lag. (Asteraceae) to two spotted spider mite, Tetranychus urticae Koch, 1836 (Atari: Tetranychidae) and bean weevil, Acanthoscelides obtectus (Say, 1831) (Coleoptera: Bruchidae) adults at 10, 15 and 20 mu L/Petri dish were investigated. Tests (contact effect for T. urticae and fumigant effect for A. obtectus) were conducted at 26 +/- 1 degrees C, 70 +/- 5% RH and 16:8 h L:D photoperiod. Mortality varied depending on plant essential oil. While the mortalities were recorded between 23 and 100% for T. urticae, they were between 45 and 100% for A. obtectus. After 72 h, when LD50 and LC50 values are taken into consideration, the most toxic plant essential oil was A. santolinoides (7.8 mu L/mite for LD50) oil for T. urticae. The most toxic plant essential oil after 72 h was A. santolinoides (0.001 mu L/insect) oil on A. obtectus adults. These results showed that the plant essential oils derived from A. absinthium, S. santonicum, S. spicigerum and A. santolinoides may be among one of the most promising alternative methods to control T. urticae and A. obtectus adults.