Acaricidal activity of orange peel citrus essential oil, commercial acaricides and their binary mixtures against adult female of Tetranychus urticae

Essential oils, are considered as an alternative to pesticides to minimize the use of environmentally hazardous chemicals . Acaricidal activity of Orange peel Citrus sinensis essential oil along with spirodiclofen and propargite was studied against twospotted spider mite,Tetranychus urticae  in laboratory. Commercial acaricides and essential oil showed superior acaricidal toxicity; with median lethal concentration (LC₅₀) values: 98.001, 615.72 and 247.89 ppm for spirodiclofen, propargite and Citrus sinensis essential oil, respectively. Moreover, these compounds were employed for working out the synergistic efficacy against adult female T. urticae. Blend of C.sinensis essential oil and spirodiclofen, at sublethal concentrations (LC₂₅ ppm), exhibited high efficacy with co-toxicity coefficient (CTC) 93.32 at 1:1 ratio. But mixing the propargite at LC₂₅ with the LC₂₅ of C.sinensis essential oil showed an antagonist effect with CTC equal to -10 at 1:1 ratio. Thus, combination of essential oil and spirodiclofen were found to be more effective than essential oil or spirodiclofen alone which could be a good ecofriendly and cost-effective approach to reduce the dose of chemicals with high residual effects.

KEY WORDS: Citrus sinensis essential oil, spirodiclofen, propargite, Tetranychus urticae, synergistic.