Bioactivity of selected plant-derived essential oils against Zabrotes subfasciatus (Coleoptera: Bruchidae)

The common bean Phaseolus vulgaris L. (Fabaceae) is an important vegetable protein source and constitutes a significant part of the diet in many tropical countries. The Mexican bean weevil Zabrotes subfasciatus (Boheman) (Coleoptera: Bruchidae) is one of the main pests affecting stored beans: it causes extensive qualitative and quantitative grain loss. We investigated the bioactivity of the essential oils extracted from Chenopodium ambrosioides L. (CA-EO), Ocimum gratissimum L. (OG-EO), and Schinus terebinthifolius Raddi (ST-EO) against Z. subfasciatus. After 12-h treatment, CA-EO and OG-EO at 20.0 μL/L of air killed 100% Z. subfasciatus, whereas ST-EO at 100.0 μL/L of air afforded 100% Z. subfasciatus mortality after 24 h. CA-EO provided the lowest 24 h LD50 (0.8 μL/L of air) and displayed efficient repellent activity against Z. subfasciatus. Our results demonstrate that CA-EO is a potentially economical and environmentally friendly alternative to manage Z. subfasciatus in stored beans.