Evaluation of fumigant toxicity of essential oils of Chinese medicinal herbs against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)

Abstract

Essential oils of sixteen Chinese medicinal plants were screened for fumigant toxicity against Bemisia tabaci. The essential oil of Allium sativum exhibited the strongest fumigant activity against B. tabaci with an LC50 value of 0.11 μg/l followed by the essential oils of Agastache rugosa (LC50 = 7.08 μg/l), Illicium verum (LC50 = 8.61 μg/l), Chenopodium ambrosioides (LC50 = 8.80 μg/l), and Syzygium aromaticum (LC50 = 13.54 μg/l). Three essential oils (Curcuma aeruginosa, Schizonepeta tenuifolia and Valeriana officinalis) did not show fumigant toxicity at a concentration of 50.00 μg/l. Chemical composition of garlic essential oil was determined using GC-MS. Two main constituents of the garlic oil, diallyl trisulfide and diallyl disulfide exhibited strong fumigant toxicity against the whitefly with LC50 values of 0.08 μg/l and 0.12 μg/l, respectively while diallyl sulfide has a LC50 value of 1.68 μg/l.