Abstract

Tetranychus urticae Koch (Acari: Tetranychidae) is one of the main pests in diverse protected and outdoor crops in the world and also in Iran. This pest has been historically controlled by chemical pesticides; however, chemical control failures and shortened residual control of abamectin were recently reported that led to the development of resistance in T. urticae. The current study aimed to develop abamectin-containing nanoliposomes/nanoniosomes by the thin-film hydration method and compare their physicochemical properties. Then, lethal and sub-lethal effects of these formulations and the commercial formulation of abamectin were examined against T. urticae under laboratory conditions (28 ± 1 °C, 60 ± 5 relative humidity, and a photoperiod of 16 h:8 h L:D). Both formulations presented high entrapment efficiency and continuous release behavior with a nanoscale size. Among tested formulations, the nanoniosomal form exhibited the most toxicity against T. urticae (LC50: 50 μg/ml). Our findings also showed that sub-lethal concentrations (LC20) of the tested formulations of abamectin exerted negative effects on T. urticae because these products enhanced the cumulative mortality of mites and reduced their performance. The population of T. urticae was treated with sub-lethal concentrations of the commercial formulation (i.e., the nanoniosomal form) and caused 8.35, 2.59, and 4.90 folds increment in one generation, respectively. However, such a formulation caused 23.06 folds increment in the population of controls. We demonstrated that in addition to commercial formulation, these stable and effective newly-designed nanopesticides could be applied for the management of such a destructive mite. © 2022, African Association of Insect Scientists.