Compatibility of Native Strains of Beauveria peruviensis and Metarhizium sp. as Strategy for Biological Control of Coffee Berry Borer (Hypothenemus hampei, Ferrari)

Abstract

Coffee is a crop of global importance, and it is especially important in countries such as Peru. However, the presence of the pest Hypothenemus hampei represents a significant challenge with a notable economic impact. This study addresses this challenge using entomopathogenic fungi such as Beauveria peruviensis and Metarhizium sp. The compatibility of three strains of Beauveria peruviensis (F5, P19, and P4) and seven strains of Metarhizium sp. (MMR-M1, LLM-M2, MHR-M4, PMR-M12, MMR-M15, TOR-M16, and GOR-M18) was evaluated for approximately 2 months. A total of 14 treatments were designed, each consisting of one strain of B. peruviensis and one strain of Metarhizium sp. The Skott–Knott test (p ≤ 0.05) revealed that strain LLM-M2 (Metarhizium sp. strain) had the highest conidial production (3.75 × 107 conidia/mL). Except for T6 (MMR-M1/F5), which showed a mutual growth type interaction (type A), all other strain combinations showed a type B interaction (mutual inhibition by contact or separation between colony margins (<2 mm)). The combination with the highest germination rate was T10 (MHR-M4/F5) at 89%. In addition, the pathogenicity of the combined strains was evaluated, showing a direct correlation with mortality and mycosis development in the coffee berry borer in treatments T1 (PMR-M12/P19), T10 (MHR-M4/F5), and T11 (MMR-M15/P19), reaching 100% mortality at 72 h with grade 4 mycosis. Regarding mycelial growth, treatments T1 (PMR-M12/P19), T4 (MMR-M1/P19), and T12 (GOR-M18/P19) reached the highest percentages, between 85.8% and 83.10% at 240 h. This study demonstrates the feasibility of using native strains of B. peruviensis and Metarhizium sp. as a biocontrol strategy against the coffee berry borer in the Amazon department, presenting them as an alternative to traditional chemical methods.