Larvicidal toxicity of Metarhizium anisopliae metabolites against three mosquito species and non-targeting organisms

Abstract

Background The fungal toxin acts as effective, low-cost chemical substances for pest control worldwide and also an alternative to synthetic insecticides. This study assessed the larvicidal potential of Metarhizium anisopliae fungi derived metabolites against Aedes aegypti, Anopheles stephensi, Culex quinquefasciatus and non-targeted organisms at 24hr post treatment. Method Isolation of entomopathogenic fungi M. anisopliae from natural traps confirmed by using 18s rDNA biotechnological tools. Crude extracts from M. anisopliae solvent extraction and their secondary metabolites were bio-assayed following WHO standard procedures against Ae. aegypti, An. stephensi and Cx. quinquefasciatus, Artemia nauplii, Eudrilus eugeniae, and Solanum lycopersicum after 24 hr exposure. Histopathological analysis of E. eugeniae treated with fungi metabolites toxicity compared to those treated with Monocrotophos after 24hrpost-treatment. M. anisopliae metabolites were characterized using GC-MS and FT-IR analysis. Results The larvicidal activity was recorded in highest concentration of 75μg/ml, with 85%, 97% and 89% mortality in Ae. aegypti, An. stephensi and Cx. quinquefasciatus respectively. M. anisopliae metabolites produced LC 50 values in Ae. aegypti, 59.83μg/ml, in An. stephensi,

Insecticidal Efficacy of Microbial-Mediated Synthesized Copper Nano-Pesticide against Insect Pests and Non-Target Organisms

“…Malaria is caused by the Plasmodium parasite carried by female Anopheles mosquitoes, filariasis by female Culex and Anopheles mosquitoes while dengue, yellow fever and zika are transmitted by Aedes pp. [ 2 , 3 ]. Tenebrio molitor (Coleoptera: Tenebrionidae) is a stored grain pest [ 4 ].…”

“…Synthetic chemical pesticides such as carbamates, organophosphorus, organochlorines and temephos are mainly to control medical and agricultural pests [ 3 , 7 ]. The repeated usage of chemicals resulted into significant drawbacks and challenges in pest control programme.…”

“…Simultaneously, entomopathogenic fungi have shown to be more effective with minimal dosages to mosquitoes and coleopteran pests [ 12 ]. Previous research shown that, Beauveria sp., Metarhizium sp., Aspergillus sp., and Fusarium sp., conidia and their chemical constituents have produced remarkable insecticidal activity on different mosquito vectors [ 2 , 3 , 8 , 9 , 10 , 13 ]. Entomopathogenic fungal derived secondary metabolites conjugated with metal nanoparticles are recommended, are eco-friendly and an improved method for disease vector control [ 3 , 14 ].…”

“…Previous research shown that, Beauveria sp., Metarhizium sp., Aspergillus sp., and Fusarium sp., conidia and their chemical constituents have produced remarkable insecticidal activity on different mosquito vectors [ 2 , 3 , 8 , 9 , 10 , 13 ]. Entomopathogenic fungal derived secondary metabolites conjugated with metal nanoparticles are recommended, are eco-friendly and an improved method for disease vector control [ 3 , 14 ]. Eco-friendly synthesized nanoparticles using botanicals, insect pathogenic fungi and bacteria are cost effective, and target specific for vector control [ 15 ].…”

Discovery of Novel Entomopathogenic Fungi for Mosquito-Borne Disease Control

“…Key stages of the infection process by entomopathogenic fungi are: (a) adhesion of infectious spores to the surface of the insect cuticle; (b) penetration of the cuticle via enzymes and mechanical force; (c) colonization of the hemocoel; and (d) emergence of the conidiophores for external sporulation on the insect cadaver (Butt et al, 2016). In addition, entomopathogenic fungi produce a variety of secondary metabolites, some of which are highly toxic to the larval, pupal, and adult mosquito stages, as well as to some pathogens such as the malaria parasite (Singh and Prakash, 2012;Niu et al, 2015;Vivekanandhan et al, 2018aVivekanandhan et al, , 2020a. A better understanding of the toxic metabolites produced by fungi can help unravel the relevant mosquitocidal mechanisms and enable the development of novel natural product-based mosquito control agents.…”