Effect of 0.1–0.5% oxalic acid dihydrate (OA) in aqueous (A) and in 50% sucrose solution (B) on mite mortality in submersion tests (n = 5 experimental series) at the end of July 2007. Different letters indicate statistically significant differences (ANOVA one-way, LSD test, aqueous solution F_4;20 = 69.5849, P = 0.000; sucrose solution F_4;20 = 38.1801, P = 0.000). There was little difference between the effectiveness of the OA in aqueous and sucrose solution at 0.1–0.5% concentrations of OA. Higher acaricidal activity was found only in the concentration of 0.1% in aqueous solution compared to the same concentration in sugar solution.