Avaliação do uso de pesticidas botânicos para o controlo do gorgulho (Callosobruchus maculatus (Fabr.,1775) na conservação das sementes de feijão nhemba

Abstract

Preserving the quality of agricultural products during storage is essential, but it is often compromised by the action of pests such as the bean weevil (Callosobruchus maculatus). Although chemical pesticides are widely used, they pose risks to human health and the environment, and promote the development of resistance. This study aimed to evaluate the efficacy of the botanical pesticides margosa (Azadirachta indica) and piri-piri (Capsicum frutescens) in controlling the weevil during the storage of cowpea (Vigna unguiculata) seeds in plastic bottles. The trial was conducted with five treatments namely: T1-Negative control (no pesticide), T2-margosa, T3-piri-piri, T4-diatomite, and T5-Actellic 25DP (positive control), in a completely randomized design with three replicates. The botanical pesticides were applied at a rate of 1.75g ​​per 175g of beans. The density, infestation level, and weight loss of the beans were evaluated over four months. ANOVA was performed using Fisher's exact test, and the comparison of means was performed using Tukey's test, both at a 5% level of significance. The results showed that the margosa and piri-piri treatments significantly reduced infestation density (2.45 and 4.76 insects/175g) and weight loss (4.97% and 6.31%), compared to the negative control (20.38 insects/175g and 12.75% loss). Margosa demonstrated efficacy close to that of Actellic, without the adverse effects of synthetic chemicals. It is concluded that the use of botanical pesticides and hermetic storage systems are a sustainable and effective alternative, being particularly promising for small producers in the conservation of cowpea seeds(TRADUÇÃO NOSSA)