Efficacy of diatomaceous earth and sulfur on some mites (Acari) under laboratory and semi-field conditions

Laboratory tests and semi-field evaluation were carried out to examine the acaricidal effect of four concentrations of diatomaceous earth (DE) and sulfur against four mites: Tetranychus urticae (Tetranychidae), Rhizoglyphus echinopus (Acaridae), Tyrophagus putrescentiae (Schrank) (Acaridae), and Amblyseius swirskii (Phytoseiidae). Results revealed that mortality increased as both time and concentration increased. Tetranychus urticae was the most affected mite; LC50 values were 70.4 and 92.0 for immature and adult stages, respectively, after 7 days. For the LC50 concentrations examined, a significant decrease in the total number of immature and adult stages of all mites during seven days was noticed. Under semi-field conditions, the LC50s were calculated for (DE) and sulfur against T. urticae on cucumber plants. The reduction percentage of T. urticae was 66.67 and 50% for (DE) and sulfur, respectively, after seven days of application, with significant differences.