The Fungus Metarhizium sp. BCC 4849 Is an Effective and Safe Mycoinsecticide for the Management of Spider Mites and Other Insect Pests

Abstract

Five isolates of Metarhizium sp. were evaluated for their pathogenicity against the spider mite (Tetranychus truncatus Ehara) (Acari: Tetranychidae) and Metarhizium sp. BCC 4849 resulted in the highest mortality (82%) on the 5th day post-inoculation (DPI). Subsequent insect bioassay data indicated similar high virulence against five other insects: African red mites (Eutetranychus africanus Tucker) (Acari: Tetranychidae), bean aphid (Aphis craccivora Koch) (Hemiptera: Aphididae), cassava mealybug (Phenacoccus manihoti Matile-Ferrero) (Hemiptera: Pseudococcidae), sweet potato weevil (Cylas formicarius Fabricius) (Coleoptera: Brentidae), and oriental fruit fly (Bactrocera dorsalis Hendel) (Diptera: Tephritidae), at mortalities of 92–99%, on 3rd–6th DPI, and in laboratory conditions. The pathogenicity assay against E. africanus in hemp plants under greenhouse conditions indicated 85–100% insect mortality on 10th DPI using the fungus alone or in combination with synthetic acaricide. Genome sequencing of Metarhizium sp. BCC 4849 revealed the high abundance of proteins associated with zinc-, heme-, and iron-binding; oxidation-reduction; and transmembrane transport, implicating its versatile mode of interaction with the environment and adaptation to various ion homeostasis. The light and scanning electron microscopy indicated that at 24 h post inoculation (PI), adhesion and appressorial formation occurred, notably near the setae. Most infected mites had stopped moving and started dying by 48–72 h PI. Elongated hyphal bodies and oval blastospores were detected in the legs. At 96–120 h PI or longer, dense mycelia and conidial mass had colonized the interior and exterior of dead mites, primarily at the bottom than the upper part. The shelf-life study also indicated that conidial formulation combined with an oxygen-moisture absorber markedly enhanced the viability and germination after storage at 35 °C for four months. The fungus was tested as safe for humans and animals, according to our toxicological assays.

First report on the enzymatic and immune response of Metarhizium majus bag formulated conidia against Spodoptera frugiperda: An ecofriendly microbial insecticide

“…Metarhizium spp., an entomopathogenic fungus with a restricted host range, safety, environmental friendliness, and ease of mass production, has been the subject of extensive research (Schrank and Vainstein, 2010;Canassa et al, 2020;Vivekanandhan et al, 2020Vivekanandhan et al, , 2022aWasuwan et al, 2021). From the arctic to the tropics, the Metarhizum genus is found all over the world.…”

Pathogenicity of Beauveria bassiana PfBb and Immune Responses of a Non-Target Host, Spodoptera frugiperda (Lepidoptera: Noctuidae)

“…Insect epidemics caused by entomopathogenic fungi can naturally suppress pest populations, reduce pesticide use, and maintain ecological balance. A wide range of entomopathogenic fungi, particularly those belonging to the Beauveria , Isaria , Lecanicillium, and Metarhizium genera, have been widely studied [ 1 , 2 , 3 , 4 ]. However, an improved understanding of the pathogenicity of entomogenous fungi is a prerequisite for evaluating pest control efficiency.…”

In vitro Evaluation of Entomopathogenic Fungi for the Management of Broad Mite, Polyphagotarsonemus latus Occurrence on Mulberry

“…Elongated hyphal bodies and oval blastospores were detected in the legs. At 96-120 h of PI or longer, dense mycelia and conidial mass had colonized the interior and exterior of dead mites, primarily at the bottom than the upper part [14].…”