Unlocking the insecticidal potential of a underexplored dryland biome: fixed oil and hydrolate of Croton heliotropiifolius against the maize weevil

Abstract

The maize weevil (Sitophilus zeamais) is one of the most damaging pests of stored grains worldwide, and its control relies heavily on synthetic insecticides, which have led to resistance development and environmental concerns. Identifying innovative, plant-derived alternatives is therefore a priority for sustainable pest management. In this context, the Brazilian Caatinga biome, one of the largest seasonally dry tropical forests in the world and still poorly explored for bioactive compounds, represents a valuable source for the discovery of novel biopesticides. This study investigated, the insecticidal potential and behavioral effects of fixed oil and hydrolate derived from Croton heliotropiifolius leaves against adult S. zeamais. Chemical characterization revealed that the fixed oil was dominated by butanoic acid (32.75%) and methyl N-methylanthranilate (32.58%), while the hydrolate was mainly composed of methyl N-methylanthranilate (25.56%) and linalool (14.65%). Both bioproducts exhibited significant toxicity and strong sublethal effects, including reduced food exploration and marked repellency (repellency index = 0.65–0.70). These findings demonstrate that C. heliotropiifolius, a native Caatinga species, is a promising source of innovative bioproducts, combining toxic and behavioral modes of action. Our results highlight the untapped biotechnological potential of Caatinga flora and support the development of plant-based biopesticides as sustainable tools for integrated pest management in stored grains.