Abstract

The acaricidal effect of two formulations of essential oil of “rika-rika” [Acantholippia deserticola Moldenke (Verbenaceae)] of 3 and 6 years of shelf life were evaluated on females of two-spotted spider mite [Tetranychus urticae (Acari: Tetranychidae)] re-gistering the repellency and effects on the oviposition. The bean leaf discs [Phaseolus vulgaris Linneo (Fabaceae)] were covered with the formulation using the immersion technique under laboratory conditions (23.31 ± 2.82 ºC, 49.70 ± 1.42% RH and 12:12 L:D photoperiod). The mortality of T. urticae was evaluated at 24, 48 and 72 hours post-application. The variables evaluated were: percentage of mortality by residual contact, percentage of repellency and number of eggs laid. Only the formulation at 1% (v/v) with 3 years shelf life reached a mortality of 50% after 24 hours of evaluation. The concentrations at 0.3% and 0.7% (v/v) with 3 years shelf life reached this value after 72 hours. None of the concentrations with 6 years shelf life reached values above 50% of mortality. A maximum mortality of 85.71% was registered in the concentration at 1% (v/v) with 3-year shelf life. The 3-year shelf life formulation showed repellent activity for the three periods evaluated (24, 48 and 72 hours), with values above 90% after 72 hours post-application. The ovisposture test revealed that the concentrations of 3 years shelf life had an inhibitory effect on the oviposition of the two-spotted spider. These results suggest a considerable acaricidal activity of the essential oil of A. deserticola with a 3-year shelf life on adult females of T. urticae.