Evaluation of the Entomopathogenic Potential of Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea for Management of Cosmopolites sordidus Germar (Coleoptera: Curculionidae)

Laura Cortada,Hendrika Fourie,James Kisaakye,Sevgan Subramanian,Danny Coyne,Shirlyne Masinde,Solveig Haukeland

doi:10.3390/agriculture11121290

Abstract

The banana weevil (BW), Cosmopolites sordidus, is the main coleopteran pest of banana, causing up to 100% yield loss. In this study, we screened 20 isolates of entomopathogenic fungi (EPF) for the management of BW. In the lab, eight Beauveria bassiana isolates caused >50% mortality of the adult BW, whereas Metarhizium anisopliae and Isaria fumosorosea isolates were less pathogenic. B. bassiana isolates ICIPE 648, ICIPE 660 and ICIPE 273 were the most pathogenic, killing ≥80% of adult BW. B. bassiana isolate ICIPE 622 yielded the highest spores per BW cadaver (1.84 × 108 spores), followed by ICIPE 660, ICIPE 273 and ICIPE 648—1.17 × 108, 3.8 × 107 and 3.6 × 107 spores, respectively. ICIPE 273 had the shortest LT50 (5.3 days) followed by ICIPE 648 (9.8 days) and 660 (11.1 days). Similarly, the LC50 values for the three isolates were 5.18 × 107, 5.49 × 107 and 5.2 × 107 spores mL−1, respectively. In the field, ICIPE 273 and ICIPE 648 had the highest (31.3%) and lowest (20.8%) pathogenicity, respectively. This study indicates that the B. bassiana isolates ICIPE 273, ICIPE 648 and ICIPE 660 are potential candidates for the environmentally sustainable management of BW.

Highlights

There was no significant effect between the repeat experiments on pathogenicity of the fungal isolates (F = 1.67, df = 1, p = 0.76), data from both experiments were pooled for analysis
Spore viability is a vital component to determine prior to screening of any entomopathogenic fungi (EPF) isolate for use as a biological control agent, as spore viability can influence the pathogenicity of EPF isolates [56]
While Wang et al [59] demonstrated that fungal conidia synthesize and store messenger RNA transcripts for future use in the production of enzymes and metabolites needed for conidial germination and virulence, they established that the type of mRNA transcripts generated is dependent on the state of the environment in which the conidia are exposed to at the time

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Banana (Musa spp.) is an important food and cash crop feeding more than 400 million people, with an annual global production estimated at approx. 167 million metric tons [1]. The estimated international trade value for banana in 2016 was US$ 11.5 billion [2]. In 2018, approximately 10% of the global banana production was produced in the East African region [1] with most of the production coming from small plots and backyard gardens

Methods

Results

Discussion

Conclusion