EXTRATOS AQUOSOS DE Mentha spicata E Lavandula angustifolia NO CONTROLE DE Sitophilus zeamais E SEUS EFEITOS NA GERMINAÇÃO DE SEMENTES DE MILHO ARMAZENADAS

Abstract

The storage of corn seeds can be compromised by the attack of Sitophilus zeamais, causing losses in quality and physiological potential. In this context, the present study aimed to evaluate the insecticidal efficiency of aqueous extracts of Mentha spicata and Lavandula angustifolia, as well as their effects on the germination of stored corn seeds and the costs associated with the treatments. The experiment was conducted in a 2 × 3 × 2 factorial design, involving two plant extracts, three concentrations (40, 70, and 100 g L⁻¹), and two types of packaging, in addition to a control treatment. The mortality of S. zeamais was evaluated over time, considering cumulative mortality at 72 hours. Extract concentrations significantly influenced mortality, with higher values observed at concentrations of 70 and 100 g L⁻¹, which did not differ from each other. Regression analysis indicated a positive relationship between concentration and mortality, with an estimated median lethal concentration (LC50) of 83.16 g L⁻¹. No effects of extract type or packaging were observed. Seed germination remained high across all treatments, indicating the absence of phytotoxicity. Cost analysis demonstrated higher costs of the extracts compared to chemical control. It is concluded that aqueous extracts present moderate and concentration-dependent insecticidal activity without compromising seed physiological quality, showing potential for use in sustainable pest management, especially as a complementary alternative in storage systems. Keywords: bioinsecticides; seed storage; germination.