A laboratory study of the acaricidal, repellent and oviposition deterrent effects of three botanical oils on Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae)

The biological activities of essential oil obtained from water distillation process of basil leaves [Ocimum basilicum L. (Lamiales: Lamiaceae)] cv Round Midnight and crude oil obtained from the cold-pressed process of chinaberry tree seeds [Melia azedarach L. (Sapindales: Meliaceae)] and a commercial neem oil product (Nimbecidine) [Azadirachta indica (A. Juss, 1830) (Sapindales: Meliaceae)] were assessed against two-spotted spider mites, Tetranychus urticae (Koch, 1836) (Atari: Tetranychidae) using a residual method on leaf disc under laboratory conditions at Bursa Uludag University during 2018-2019. The lethal concentrations (LC50 and LC90) of Nimbecidine, chinaberry and basil oils were estimated as 0.8 and 1.8 mg/L, 4.0 and 6.9%, 5.4 and 11.7%, respectively, 72 h after treatment. The lethal times (LT50 and LT90) of Nimbecidine (1 mg/L), chinaberry (6%) and the basil (8.4%) were 64 and 107 h, 41 and 73 h, 65 and 110 h, respectively. The females had a strong aversion to bean leaf surfaces sprayed with the sublethal concentrations of Nimbecidine (0.125-0.75 mg/L), chinaberry (0.75-3%) and basil (0.7-1.4%) oils. Significant decreases were recorded in the number of eggs laid on bean leaves sprayed with the sublethal concentrations for Nimbecidine (0.031-0.5 mg/L), chinaberry (0.75-3%) and the basil (1.4-5.6%) oils compared with unsprayed bean leaves. The study showed that the assessed concentrations of the oils obtained from the basil and chinaberry compared to the commercial botanical product (Nimbecidine) have similar biological effects on T. urticae.