Bioactivity of extracts of Ocimum campechianum in the development of Ascia monuste orseis

Abstract

The caterpillar Ascia monuste orseis (Godart) (Lepidoptera: Pieridae) stands out as one of the main defoliating pests of brassicas. To mitigate the damage and reduce the impact on human health and the environment that results from the persistent and indiscriminate use of chemical insecticides, it is crucial to consider the use of botanical insecticides as a fundamental alternative for pest control. The aim was therefore to investigate the stimulus-response of the hydroalcoholic crude extract of Ocimum campechianum and of its dichloromethane (DCM) fraction on A. monuste orseis. Leaf consumption (cm2) of caterpillars exposed to the extract, caterpillar mortality in 24 h, total caterpillar mortality, pupal mortality, pupal period duration, and morphological malformation in adults were evaluated. Feeding the caterpillars for eight days with cabbage impregnated with the crude extract and its DCM fraction resulted in decreased caterpillar feeding, increased larval mortality (90%), lengthening of the pupal period (two days), and an increase in adult deformation (50%). Therefore, the crude extract of O. campechianum and its DCM fraction have potential for use in the alternative control of A. monuste orseis.