Efficiency of diatomaceous earth, silica nanoparticles, kaolin, micronized sulfur and their mixing on Tetranychus urticae Koch. in greenhouse conditions

Two spotted mite, Tetranychus urticae Koch. is one of the most important plant pests. Chemical pesticides are used to control this pest, which increases pesticides residual, eliminates natural enemies and contaminates groundwater. In this regard, the effect of diatomaceous earth, silica nanoparticles, kaolin and micronized sulfur and their mixing on different biological stages of two spotted mite were evaluated in laboratory condition. The results of probit analysis showed that the LC50 of nano silica was equal to 180.00 mg/L after five days for egg stge. For third nymphal and adult stages the LC50 were 30.51 and 43.01 after 72 hours respectivly. In studying the effect of mixing the compounds, the highest lethal effect against eggs, 3rd nymphal stage and adult mites was obtained by mixing sulfur and nanosilica. Comparison of the average effect of diatomaceous earth, nanosilica, kaolin, sulfur treatments and their combination on leaf chlorophyll index showed that the highest index was in sulfur treatment (42.53). Also, the least oviposation and production of offspring was observed in mixing of sulfur with nanosilica. Due to the significant effect of sulfur and nanosilica mixing, thus, it can be used in integrated pest management program against eggs, 3rd nymphal stage and adult of this pest.