Prospects of Botanical Biopesticides in Insect Pest Management

Abstract

The essential oils of six plant species [peppermint, Mentha piperita, and bergamot mint, Mentha citrata (both, Lamiales: Lamiaceae); blue gum, Eucalyptus globulus (Myrtales: Myrtaceae); lemongrass, Cymbopogon citratus, and khus grass, Vetiver zizanoides (both, Poales: Poaceae), and turmeric, Curcuma longa (Ziniberales: Zingiberaceae)] were screened for repellent, larvicidal and pupicidal activities against the housefly, Musca domestica L. (Diptera: Muscidae). Subsequently, emulsifiable concentrate (EC) formulations of the two most effective oils were prepared and tested in the laboratory as well as in the field. In repellency bioassays, M. piperita (RC(84) , 61.0 µg/cm(2) ) was found to be most effective, followed by E. globulus (RC(84) , 214.5 µg/cm(2) ) and C. citratus (RC(84) , 289.2 µg/cm(2) ). Formulated M. piperita and E. globulus showed RC(84) values of 1.6 µg/cm(2) and 4.1 µg/cm(2) , respectively. Formulated M. piperita and E. globulus achieved larval mortality (LC(50) ) in 72 h at 5.12 µg/cm(2) and 6.09 µg/cm(2) , respectively. In pupicidal bioassays, crude oils of M. piperita and E. globulus suppressed the emergence of adult flies by 100%. Field experiments with the M. piperita formulation showed reductions in fly density (number of flies/h) of 96% on treated cattle and 98% on treated plots. This study demonstrates the effectiveness of EC formulations of selected essential oils in reducing housefly populations in field conditions.