Phenotypic, molecular, and virulence characterization of entomopathogenic fungi, Beauveria bassiana (Balsam) Vuillemin, and Metarhizium anisopliae (Metschn.) Sorokin from soil samples of Ethiopia for the development of mycoinsecticide

Abstract

Fungal entomopathogens are the most effective biocontrol agents against insect pests in the natural ecosystem. This study was conducted for phenotypic, molecular, and virulence characterization of locally isolated entomopathogenic fungi from soil samples of six localities in Ethiopia. Entomopathogenic fungi were isolated from 120 soil samples with the galleria baiting method. A total of 65 (54.2%) entomopathogenic fungal isolates belongs to Beauveria spp and Metarhizium spp were identified based on cultural and morphological features. All isolates were pre-screened based on germination, vegetative growth rate, and spore production as fungal in-vitro virulence determinates. Isolate AAUKB-11 displayed the peak germination of 99.67% and isolate AAUMFB-77 achieved the highest radial growth rate of 3.43 mm day À1 with the highest sporulation 4.60 Â 10 8 spores/ml. The phylogenetic analysis of ITS-rDNA confirmed that 7 isolates were identified as B. bassiana and 5 isolates were categorized into M. anisopliae. Selected B. bassiana and M. anisopliae strains were evaluated for their pathogenicity efficiency against G. mellonella larvae and caused 86.67%-100% mortality. The mortality rates of G. mellonella larvae peaked at 100% with 4(33.33%) isolates from B. bassiana and 2(16.67%) isolates from M. anisopliae after 10 days of treatments. The high virulent isolate, B. bassiana AAUMB-29 displayed the least LT 50 value of 2.36 days followed by isolate B. bassiana AAUMFB-77 with LT 50 of 2.53 days. Future studies should be needed to focus on the evaluation of high virulent isolates against other potential insect pests to assess their vigorous role as favorable biological control agents.

DNA barcoding reveals the natural occurrence of Beauveria bassiana (Balsamo) Vuillemin in two-spotted spider mite, Tetranychus urticae Koch in Bhendi [Abelmoschus esculentus (L.) Moench] ecosystem in Coimbatore district of Tamil Nadu

“…2021) characterized the EPF morphologically indicating the presence of white or yellowish white colony, globose or sub-globose conidia were essential for the confirmation of B. bassiana. In the present study, the isolated EPF isolates produced whitish and yellowish white colony, globose and sub-globose conidia were in accordance with the findings of (Gebremariam et al 2021).…”

Identification and evaluation of isolated entomopathogenic fungus from Egyptian soil against the black cutworm larvae of Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae)

“…Vänninen et al (2000) tested the persistence of EPF using 4 types of soil (clay, peat and 2 types of sand) and found that clay was the most suitable soil for persistence. Variations in the occurrence of EPFs from different sample sites could be due to the influence of biotic and abiotic factors including availability of insect hosts, temperature, humidity, UV radiation, soil type and organic matter in addition to application of chemical pesticides (Gebremariam et al 2021).…”

Organomineral fertilizer application enhances Perilla frutescens nutritional quality and rhizosphere microbial community stability in karst mountain soils

“…The keystone genus of the bacterial community in the OMF group was Pseudomonas , and the keystone genus of the fungal community was Metarhizium ( Supplementary Table S3 ), both of which are recognized as biocontrol microorganisms. Pseudomonas can adsorb heavy metals in soil and promote plant growth ( Costa-Gutierrez et al, 2020 ; Ghorbanzadeh et al, 2020 ; Wu et al, 2022 ), whereas Metarhizium can kill plant pests and mitigate plant diseases ( Riguetti Zanardo Botelho et al, 2019 ; Gebremariam et al, 2021 ; González-Pérez et al, 2022 ). In conclusion, this study demonstrated that the application of organic fertilizer, especially OMF, can not only enhance the connectivity, cohesiveness and stability of microbial community network structure, but also increase the abundance of beneficial microorganisms.…”