Biopesticide Activity of Guayule Resin.

The extensive use of synthetic pesticides has created considerable concern for both human health and the environment, which has prompted the search for safer alternatives, such as the resin of guayule (). Thus, in the present study, we aimed to test the biopesticide activity of crude guayule resin and three derived fractions and compare them to reference products that act against four of the most economically significant plant pests: , , and . None of the guayule products caused plant damage. The crude guayule resin and the hexane and ethyl acetate fractions displayed moderate to high contact mortality against and , as well as moderate to high antifeedant activity against , and . No significant activity was observed against . A correlation analysis of the activity and fraction composition revealed that guayulins C and D, isoargentatins A and B, argentatins A, B and D and an unknown compound C6 were likely responsible for the contact mortality. By contrast, the antifeedant activity appeared to be caused by guayulins A and B against and and by guayulins C and D and argentatin B against . The feeding reduction in was associated with an unknown compound C2 and argentatin C. Therefore, guayule appears to be a promising novel biopesticide.