Biological Control of Sweet Potato Weevil Using Metarhizium anisopliae: A Step Toward Eco-friendly Pest Management

Abstract

This study aims to evaluate the potential of the entomopathogenic fungus Metarhizium anisopliae as a biological control agent against sweet potato weevil. Sweet potato weevil (Cylas formicarius) is a major pest of sweet potato crops, causing severe economic losses due to its ability to infest both storage roots and vines. Concerns regarding the ecological health risks posed by chemical insecticides in sweet potato farming, a natural approach were tested as an alternative method for controlling this pest. This study evaluates the potential of the entomopathogenic fungus Metarhizium anisopliae as a biological control agent against sweet potato weevil. Laboratory experiments were conducted to compare the effectiveness of different strains of M. anisopliae and other entomopathogens, using two application techniques: "dipping" and "ingestion." Results demonstrated that M. anisopliae significantly increased Sweet potato weevil (SPW) mortality, with the "ingestion" method rather than "dipping" method across all treatments. Among the tested strains, M. anisopliae (MR) showed the highest mortality rate (62.47%) when applied through ingestion. The findings highlight that both the choice of fungal strain and application technique are critical for optimizing pest control outcomes. The study also underscores the advantages of M. anisopliae as an eco-friendly alternative to chemical pesticides, with potential to reduce environmental impact while maintaining effective pest management. Furthermore, the results emphasize the importance of integrating biological control agents with precise application methods to enhance pest control efficacy. This research contributes to sustainable agriculture by promoting the use of entomopathogenic fungi as part of integrated pest management strategies. Further research is suggested to assess the field-level use of M. anisopliae under varying environmental conditions, aiming to establish its effectiveness in large-scale sweet potato cultivation in order to reduce reliance on chemical pesticides. However, field studies are needed to reach a good conclusions and practical applications.