Efficacy of a Bt-based biopesticide formulation of the Kurstaki HD1 variety against Spodoptera frugiperda larvae

Maize cultivation is subject to many constraints that cause yield reduction. Spodoptera frugiperda is one of the insect pests of this crop in Côte d’Ivoire. In recent years, microbial insecticides have become a viable alternative to control the armyworm and are considered a safe tool in integrated pest management. Various Bt-based biopesticide formulations were tested on the armyworm larvae to identify the most effective ones. A rearing of S. frugiperda was carried out in the entomology laboratory of University Nangui Abrogoua. Thus, larvae from L1 to L6 stages were tested. Successive decimal dilutions of bacterial suspension of Btk HD1 were made, and five different doses of each biopesticide and a control were used. All bioinsecticides tested had an effect on the mortality of the larvae. However, the biopesticide formulation M10 had a much greater effect on the mortality for the most concentrated dose (1011 spores/mL) with a mortality rate of 92.1% followed by the M5 formulation with a mortality rate of 76.9% at a dose of 8.6×1010 spores/mL. For the M15 formulation, only the first dose D1 at 4.6×1011 spores/mL killed 50% of the stage 2 larvae, whereas the M0 formulae at the most concentrated dose of 1.3×1011 spores/mL, produced a mortality rate of 26.7%. The M10 formulae can be used in integrated pest management scheme against S. frugiperda. published by the Journal of Biodiversity and Environmental Sciences | JBES