LAUSR

Essential oils of Mentha pulegium (Lamiaceae) have shown a high potential for use in pest control. In the present study we examined the comparative potential of the M. pulegium essential oils representing pulegone (EO1) and piperitone (EO2) chemotypes for the control of three serious crop pests, along with their side effects on a beneficial insect. In the case of Tetranychus urticae, the mortality rate of females sprayed at the concentration of 500 μL/L was 68.5% and 71%, for EO1 and EO2 respectively, while the mortality rate at 1000 μL/L was 86% and 92.5%, which were significantly higher compared to the control (21%). In the experiments on Aphis gossypii, the sprayings were held under greenhouse conditions at 1000 μL/L. The mortality rate caused by EO1 was 82% and that of EO2 was 88%. In the control treatment dead aphids were not observed. The results on the third pest, Aphis spiraecola, showed a mortality rate of 40% and 48% for the EO1 and EO2 chemotype, respectively, at 500 μL/L. Interestingly, the mortality caused by both essential oils on the polyphagous predator Nesidiocoris tenuis was not significantly different to the control treatment. All this evidence suggests that the effects of both M. pulegium essential oil chemotypes are equally effective in the control of the pests tested, causing only minor effects on a beneficial insect. Therefore, due to the constraints reported for the pulegone use in pest control, the piperitone-based chemotype can be a valuable source for new crop protection products with the aim of being compatible with modern Integrated Pest Management strategies.