Essential oil of spiked pepper, Piper aduncum L. (Piperaceae), for the control of caterpillar soybean looper, Chrysodeixis includens Walker (Lepidoptera: Noctuidae)

Abstract

The resistance of pests to insecticides and the high costs of pest control have prompted a search for less harmful alternatives to the environment. Phytoinsecticides can be a promising option in the control of pests. The insecticidal properties of the essential oil of Piper aduncum L. (Piperaceae) have been demonstrated by several authors. This study was aimed at evaluating the insecticidal activity of P. aduncum essential oil on caterpillars of the soybean looper, Chrysodeixis includens Walker. Two bioassays were conducted: The first was based on the ingestion of treated leaves, while the second, on direct contact. Chromatography was performed, and the resulting oil was used to treat larvae fed cotton leaves at the concentrations of 0.5, 1.0, 2.0, 4.0, and 8.0%. The controls consisted of water and acetone. The first assessment was carried out 24 h after the application. The main compounds identified by chromatography were dillapiole, myristicin, and Z-carpacin. In the ingestion bioassay, mortality reached 90% for the highest concentration in the first 24 h after application. For the topical application of P. aduncum essential oil, no significant differences were observed until the end of the life cycle of C. includens. This study demonstrates the insecticidal activity essential oil of P. aduncum on C. includens and its potential in the control of this insect by ingestion.