Comparative toxicity of <i>Rosmarinus officinalis</i> L. essential oil and blends of its major constituents against <i>Tetranychus urticae</i> Koch (Acari: Tetranychidae) on two different host plants

Abstract

Abstract Bioassays of Rosmarinus officinalis L. essential oil and blends of its major constituents were conducted using host‐specific strains of the two‐spotted spider mite, Tetranychus urticae Koch, on bean and tomato plants. Two constituents tested individually against a bean host strain and five constituents tested individually against a tomato host strain accounted for most of the toxicity of the natural oil. Other constituents were relatively inactive when tested individually. Toxicity of blends of selected constituents indicated a synergistic effect among the active and inactive constituents, with the presence of all constituents necessary to equal the toxicity of the natural oil. Copyright © 2006 Society of Chemical Industry