Effect of extracts of Citrus sinensis (Rutaceae) and Trichilia havanensis (Meliaceae) in mortality and repellence of Tetranychus urticae (Acari: Tetranychidae)

Abstract

This work aimed to evaluate the effect of the plant extract from the peel of Citrus sinensis and the seeds of Trichilia havanensis on mortality and repellency in different biological states of Tetranychus urticae under laboratory conditions. Solutions of the extracts at 500, 1000 and 1500 mg.L-1 were applied to a known number of eggs, larvae, and female adults of T. urticae in foliar discs of bean (Phaseolus vulgaris L.). The data analysis of mortality percentage and the repellence (Kruskal-Wallis test and comparison of medians, (α=0.05) showed that the extract of T. havanensis presented the highest percentage of mortality in eggs with 45.0 % at 1500 mg.L-1, and the extract of C. sinensis presented the highest mortality in larvae with 40.0 % at 1000 mgL-1, and adults with a 50.0 % at 1500 mg.L-1. The highest percentage of repellency was the extract of C. sinensis at 1500 mg.L-1, with 30 % in larvae and 60.0 % in adults. The results indicate that the extracts have the potential to develop effective products for managing T. urticae.