Myrciaria floribunda is a plant found in the Northeast region of Brazil with several insecticidal properties that remain little explored. In this sense, this study aims to investigate the harmful effects of essential oil (EO) from M. floribunda leaves against Sitophilus zeamais, an important corn pest. The EO was applied in toxicity tests by fumigation, contact, and ingestion, as well as in in vitro assays to evaluate its effects on the activity of the enzymes α-amylase, trypsin, and acetylcholinesterase. Chromatographic analysis of the oil revealed (E)-caryophyllene (56.41%), viridiflorol (4.02%) and α-selinene (3.85%) as the main compounds. The essential oil (EO) showed fumigation toxicity, with an LC50 of 3.2 μL/L of air, and (E)-caryophyllene with an LC50 of 3.97 μL/L of air. The EO inhibited insect feeding, altering growth rate and feed conversion efficiency starting at 62.5 μL/g. In this study, an increase in amylase and acetylcholinesterase (AChE) activity was observed. This increase in AChE activity may cause an imbalance in the nervous system, leading to insect death. Thus, the EO of M. floribunda may serve as an alternative for the control of S. zeamais in stored corn and help prevent significant post-harvest losses for farmers.
Anselmo et al. (Tue,) studied this question.