New acaricidal activities and chemical compositions of orange oil and extracts of (wild mint and henna) against Tetranychus urticae Koch (Acari.:Tetranychidae)

Abstract

Two-spotted spider mite, Tetranychus urticae Koch (Acari.: Tetranychidae), is an economic pest causing high damages to different crops (Vegetables, flowers and fruits) in worldwide including Egypt. The acaricidal activities of orange peels oil (Citrus sinensis L. variety navel) and methanol leaves extracts of (Wild mint, Mentha longifolia L. and Henna, Lawsonia inermis Linn.) were evaluated against the adult females of this mite at four different concentrations (1250, 2500, 5000, 10,000 ppm), after 24 and 48 hrs under laboratory conditions. Laboratory bioassay results indicated that orange peels oil and methanol leaves extracts of (Wildmint and Henna) caused high mortality of adult females of T. urticae at the highest concentration (10,000 ppm) after 48 hrs. Orange peels oil achieved the highest toxicity against T. urticae followed by wild mint extract, while, henna extract recorded the lowest toxicity. The acaricidal activities are concentration dependent. The mean lethal concentrations (LC50) values of orange peels oil, henna and wild mint leaves extracts were 2203, 4642 and 5114 ppm, respectively. The chemical compositions of the orange peels oil and two leaves extracts of wild mint and henna were analysed and identified by GC–MS. The principal compounds present in orange peels oil were D-Limonene (92.42%), linalool (2.13%) and myrcene (1.30%), whereas, the major constituents in wild mint extract are Pulegone (38.61%), Menthol (24.93%), Trans Menthone (14.32%) and Cis-Menthone (7.93%). For henna extract, 2-Hydroxy-1,4-napthoquinone (Lawsone) (15.26%), Turanose (13.65%) and Methyl-α-D-glucofuranoside (12.08%), were the main components. Our results concluded that, orange peels oil was the most potent against the T. urticae and can be used as alternative and safe acaricidal agents T. urticae control.