Effect of Coumarin and gallic acid, Allelochemics, on survival, development and reproduction of the twospotted spider mite, Tetranychus urticae (acari: Tetranychidae)

Abstract

Coumarin and gallic acid decreased survival and reproduction of the twospotted spider mite, Tetranychus urticae Koch. Contacting treated leaves with both compounds at 250 ppm caused mortality and low reproduction when the time of exposure increased gradually from 2 h to 144 h. Survival of the immatures decreased when contacted treated discs although development periods and reproduction were normal. Treatment of eggs caused low mortality although high concentrations shortened the hatch time.