New Record of Metarhizium brunneum Infecting Banana Weevil in Peru: Implications for Biological Control

Area of Science:

• Agricultural Entomology
• Biological Control
• Mycology

Background:

• Entomopathogenic fungi offer a sustainable alternative to chemical insecticides in tropical agroecosystems.
• The banana weevil (Metamasius hemipterus) poses a significant threat to banana cultivation worldwide.
• There is a need for effective and environmentally friendly pest management strategies.

Purpose of the Study:

• To isolate and identify an entomopathogenic fungus for biological control of Metamasius hemipterus.
• To characterize the physiological and pathogenic properties of the identified fungal isolate.
• To evaluate the potential of the fungus as a biological control agent in banana plantations.

Main Methods:

• Isolation of entomopathogenic fungi from infected Metamasius hemipterus adults in Peruvian banana plantations.
• Multilocus phylogenetic analysis (using tef1α, β-tubulin, rpb1, and rpb2 sequences) for taxonomic identification.
• Physiological characterization (growth, thermal response, conidial production) and pathogenicity assays (LC50 determination).

Main Results:

• A Metarhizium brunneum isolate (PM9) was identified and confirmed through phylogenetic analysis.
• Isolate PM9 showed high conidial yield on rice substrate and exhibited variability in growth and thermal response.
• Pathogenicity assays demonstrated high virulence against adult Metamasius hemipterus, with LC50 of 2.91 × 10^5 conidia·mL^-1 and >90% mortality at high concentrations.

Conclusions:

• Metarhizium brunneum isolate PM9 possesses desirable physiological and pathogenic traits for effective biological control of Metamasius hemipterus.
• The natural occurrence of this entomopathogen suggests ecological adaptation to local conditions, supporting its use in integrated pest management.
• Further field-based evaluations are necessary to confirm the efficacy and implementation of this biological control agent in commercial banana production.