Evaluation of the effectiveness of an insect growth regulator (Lufenuron 50 g/l) in the protection of corn against the fall armyworm (Spodoptera frugiperda J.E. Smith) in Burkina Faso

Titre courant : Efficacité d’un régulateur de croissance des insectes contre la chenille légionnaire d’automne au Burkina Faso

Abstract

The fall armyworm (Spodoptera frugiperda J.E. Smith), identified in Burkina Faso in 2017, poses a threat to food security. The use of insecticides from the same family can lead to resistance in S. frugiperda. One of the alternatives to remedy this is the use of new chemical molecules such as insect growth regulators. This study aims to evaluate the effectiveness of a growth regulator on S. frugiperda larvae, Lufenuron, an insecticide that blocks the molting process. Susceptibility tests were carried out on L1 to L5 stage larvae in the laboratory at the Farako-Bâ research station. Also, the effectiveness of this growth regulator was evaluated on the insect pest at the Bama station during the dry 2022/2023 and rainy 2023 campaigns. Laboratory results showed that corn leaves treated with Lufenuron cause mortality of larvae by slowing their growth. The 25 ml dose was the most effective with mortality of between 75% and 85% of L1 to L5 stage larvae. In the field, the results also indicated an effectiveness of the growth regulator on the larvae. In dry countryside, doses of 375 ml/ha, 500 ml/ha and 750 ml/ha of Lufenuron were equivalent to Emamectin benzoate 200 g/ha. The rate of attacked plants was between 1.04% and 1.73% for the 3 doses of Lufenuron and the rate of attacked ears was between 8.73% and 10.84%. In the rainy countryside, the same trend was observed. The plant attack rate was between 0.46% and 0.82% for the 3 doses of Lufenuron. These results demonstrate the possibility of using this growth regulator in the management of corn armyworm.