Abstract

Maize (Zea mays) is one of the pillars of global food security and an important foodstuff for African households. This cereal is targeted by numerous pests during storage, the most harmful of which is the larger grain borer, Prostephanus truncatus. This harmful insect was recently discovered in maize stocks in northern Côte d'Ivoire, where protection methods are still unsuccessful. The objective of this study was to evaluate the biocidal and repellent activities of three plant extracts in order to propose them as biopesticides for the effective protection of maize stocks. Tests carried out using essential oils of Eucalyptus citriodora, Cymbopogon citratus and Ocimum gratissimum showed a repellent effect against adults and a biocidal effect on eggs, larvae, pupae and adults of P. truncatus. The lethal concentrations (LC50) values were 14.16 µL/L for E. citriodora, 16.09 µL/L for C. citratus and 25.84 µL/L for O. gratissimum. These essential oils reduced the lifespan of P. truncatus adult by 98.62±0.46% during contact treatments. Their action inhibited the development of the immature stages of this pest. This study showed that essential oils can reduce P. truncatus populations and may serve as effective biopesticides.