Repellent and Oviposition-Deterring Effects of Hop Beta-Acids on the Two-Spotted Spider Mite<i>Tetranychus urticae</i>

Abstract

Colupulone, the main component of the beta-acid fraction of hop extracts, was shown to repel the two-spotted spider mite Tetranychus urticae Koch from the surface of plant leaves. The total beta-acid fraction was found more effective in repelling the mites and reducing the number of eggs laid than colupulone at equivalent concentrations, suggesting that other components of the extract have repellent and oviposition-deterring effects.