Abstract
Spodoptera frugiperda, known as the fall armyworm, is a highly destructive pest that greatly impacts worldwide agriculture, particularly maize and other key crops. Its rapid expansion and resistance to standard insecticides pose a significant threat to food security. As a result, effective and long-term pest management solutions are required. In this context, microbial biocontrol agents, such as Saccharomyces cerevisiae, offer an environmentally friendly alternative to chemical pesticides. This study investigates S. cerevisiae's efficiency as a biocontrol agent against S. frugiperda. The S. cerevisiae HA-NY4 strain was evaluated for larvicidal activity as well as its effect on insect metabolism and development. The results showed that S. cerevisiae HA-NY4 significantly increased larval mortality after 72 h of treatment. Furthermore, it caused metabolic abnormalities in the larva, including reduced protein synthesis, impaired carbohydrate metabolism, and developmental defects. These effects resulted in delayed pupation, lower pupal weight, and decreased adult emergence, thereby restricting the pest's reproductive potential. The main goal of this study was to evaluate the effectiveness of the S. cerevisiae HA-NY4 strain, thus providing a sustainable and environmentally friendly solution to manage S. frugiperda infestations.