Biocontrol effects of chemical molecules derived from Beauveria bassiana against larvae of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

In this study, we conducted tests on the isolation, identification, characterization, and extraction of chemical molecules from Beauveria bassiana against Tuta absoluta larvae. The enzyme responses of T. absoluta to the crude extract were examined 24 h after treatment, and the number of dead larvae was calculated 24 and 48 h after treatment. Molecular docking studies were conducted to assess the interaction of important molecules with the acetylcholinesterase enzyme. The larvicidal activity of crude chemicals from fungi was high 24 h after treatment, with LC50 and LC90 values of 25.937 and 33.559 μg/mL, respectively. For a period of 48 h, the LC50 and LC90 values were 52.254 and 60.450 μg/mL, respectively. The levels of acetylcholinesterase, α-carboxylesterase, and β-carboxylesterase enzymes were lower in the treatment group after 24 h compared to the control group. The GC-MS test revealed that the crude extract consisted mainly of 9,10-octadecadienoic acid, which was the primary compound. Docking results indicated that 9,10-octadecadienoic acid showed a strong interaction with acetylcholinesterase (AChE). Our findings suggest that the chemical molecule 9,10-octadecadienoic acid derived from the entomopathogenic fungus B. bassiana is more toxic to T. absoluta larvae. We plan to conduct studies to test its effectiveness in semi-field conditions and to evaluate its stability in field conditions. We believe that this 9,10-octadecadienoic acid molecule could be used to control T. absoluta larvae in the near future without causing environmental pollution

Toxicity of Metarhizium flavoviride conidia virulence against Spodoptera litura (Lepidoptera: Noctuidae) and its impact on physiological and biochemical activities

Insect pests of agricultural crops have establish immunological tolerance against fungal infection caused by pathogens via different humoral and cellular processes. Fungal infection can be prevented by insect antioxidant and detoxifying enzymes, but there is no clear understanding of how they physiologically and biochemically interact. Our study aims to examine the antioxidant and detoxifying enzyme defense systems of the pest insect Spodoptera litura in response to infection by Metarhizium flavoviride. At 48 h following exposure to M. flavoviride, antioxidant enzyme levels were modified, and phenoloxidase and total hemocyte count were decreased significantly. The amount of detoxifying enzymes increased significantly. M. flavoviride appears to directly affect the S. litura immune system and results in decreased immunity. In a bioassay, M. flavoviride was found to be harmful to S. litura larvae in their third and fourth instar stage. M. flavoviride may be an effective tool in the control of S. litura larvae. Such entomopathogenic fungi represent cheaper, pollution free, target specific, promising alternatives to synthetic chemical tools in the for control insect pests

Classification, biology and entomopathogenic fungi-based management and their mode of action against Drosophila species (Diptera: Drosophilidae): a review

This review provides a comprehensive analysis of the classification, biology, and management of Drosophila species (Diptera: Drosophilidae) with a focus on entomopathogenic fungi (EPF) as a biocontrol strategy. Drosophila species, particularly Drosophila suzukii, and Drosophila melanogaster have emerged as significant pests in various agricultural systems, causing extensive damage to fruit crops. Understanding their taxonomic classification and biological traits is crucial for developing effective management strategies. This review delves into the life cycle, behavior, and ecological interactions of Drosophila species, highlighting the challenges posed by their rapid reproduction and adaptability. The review further explores the potential of EPF as an eco-friendly alternative to chemical pesticides. The mode of action of EPF against Drosophila species is examined, including spore adhesion, germination, and penetration of the insect cuticle, leading to host death. Factors influencing the efficacy of EPF, such as environmental conditions, fungal virulence, and host specificity, are discussed in detail. By synthesizing current research, this review aims to provide valuable insights into the application of EPF and to identify future research directions for enhancing the effectiveness of EPF-based control measures against Drosophila species

Biology, classification, and entomopathogen-based management and their mode of action on Tuta absoluta (Meyrick) in Asia

Tuta absoluta, known as the South American tomato leaf miner, significantly impacts tomato plants (Solanum lycopersicum) economically on a global scale. This pest, belonging to the Gelechiidae family, is native to South America and was first identified in Peru in 1917. Since its discovery, T. absoluta has rapidly spread to Europe, Africa, and Asia, severely threatening tomato production in these regions. The widespread application of chemical pesticides against this pest has resulted in significant environmental harm, including contamination of soil and water, and has had negative effects on non-target species such as beneficial insects, birds, and aquatic life. Although substantial research has been conducted, biological control methods for T. absoluta remain insufficient, necessitating further study. This review covers the Biology, Classification, and Entomopathogen-Based Management of T. absoluta (Meyrick) in Asia. It provides essential insights into the pest’s life cycle, ecological impacts, and the potential of entomopathogens as biocontrol agents. The detailed information presented aims to facilitate the development of sustainable pest control strategies, minimizing environmental impact and promoting the use of entomopathogens as viable alternatives to chemical pesticides in controlling T. absoluta insect pest

Entomopathogenic fungi based microbial insecticides and their physiological and biochemical effects on Spodoptera frugiperda (J.E. Smith)

Background‘The fall armyworm, Spodoptera frugiperda’, represents a significant threat to maize production, a major staple crop in Asian countries.MethodsIn pursuit of more effective control of this insect pest, our study assessed the physiological and biochemical effects of the entomopathogenic fungus Metarhizium anisopliae against the larvae of S. frugiperda.ResultsResults revealed that, following nine days of treatment, a high concentration of conidia (1.5x107 conidia/mL-1) was toxic to all stages of larvae (second to fifth instar), resulting in 97% mortality of the second instar, 89% mortality of the third instar, 77% mortality of the fourth instar, and 72% mortality of fifth instar. All larval instars were found to have dose-dependent mortality effects. Treated S. frugiperda larvae further displayed significant physiological, morphological, and behavioral changes. Here, treated larvae displayed significantly lower levels of acetylcholinesterase, α-carboxylesterase, and β-carboxylesterase enzyme activity when compared to control groups. Treated larvae underwent an outward morphological change as the result of a decrease in the exterior cuticle of the anal papillae and a demelanization of the interior cuticle. Treated larvae also exhibited abnormal feeding behaviors as a consequence of the negative impact of conidia treatment on the neuromuscular system. Investigation into the effect of M. anisopliae on the non-target organism, the earthworm Eudrilus eugeniae, revealed that M. anisopliae conidia did not produce significant pathogenicity following three days of treatment. Furthermore, histological analysis revealed no significant effect of the entomopathogenic fungi on the gut tissue of the non-target organism.ConclusionThis study highlights the potential of M. anisopliae in the control of S. frugiperda

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

Entomopathogenic fungi from microbial sources are a powerful tool for combating insecticide resistance in insect pests. The purpose of the current study was to isolate, identify, and evaluate bag-formulated entomopathogenic fungal conidial virulence against insect pests. We further investigated the enzymatic responses induced by the entomopathogenic fungi as well as the effect on a non-target species. Entomopathogenic fungi were isolated from the Palamalai Hills, India, using the insect bait method, and the Metarhizium majus (MK418990.1) entomopathogen was identified using biotechnological techniques (genomic DNA isolation and 18S rDNA amplification). Bag-formulated fungal conidial efficacy (2.5 × 103, 2.5 × 104, 2.5 × 105, 2.5 × 106, and 2.5 × 107 conidia/ml) was evaluated against third instar larvae of Spodoptera frugiperda at 3, 6, 9, and 12 days of treatment, and acid and alkaline phosphatases, catalase, and superoxide dismutase enzymatic responses were evaluated at 3 days post-treatment. After 12 days of treatment, non-target assays on the earthworm Eudrilus eugeniae were performed using an artificial soil assay. Results of the bag formulated fungal conidial treatment showed that S. frugiperda had high susceptibility rates at higher concentrations (2.5 × 107 conidia/ml) of M. majus. Lower concentration of 2.5 × 103 conidia/ml caused 68.6% mortality, while 2.5 × 107 conidia/ml caused 100% mortality at 9 days post treatment. Investigation into enzymatic responses revealed that at 3 days post M. majus conidia exposure (2.5 × 103 conidia/ml), insect enzyme levels had significantly changed, with acid and alkaline phosphatases, and catalase enzymes significantly reduced and superoxide dismutase enzymes significantly raised relative to the control. After 12 days of treatment, no sublethal effects of M. majus conidia were observed on E. eugeniae, with no observed damage to gut tissues including lumen and epithelial cells, the nucleus, setae, coelom, mitochondria, and muscles. This study offers support for the use of fungal conidia in the target-specific control of insect pests

Enzymatic, cellular breakdown and lysis in treatment of Beauveria Brongniartii on Spodoptera litura (Fabricius, 1775)

Abstract The current study aimed to isolate Beauveria brongniartii conidia from forest soils, identify the fungus, and evaluate its effectiveness on the eggs, larvae, pupae, and adults of Spodoptera litura. Insect mortality rates were recorded every 3, 6, 9, and 12 days. The identification of entomopathogenic fungi was carried out using molecular techniques, including PCR, DNA sequencing, and molecular markers, to detect species-specific 18 S rDNA genetic sequences, all performed under aseptic conditions. The results indicated that higher conidia concentrations (2.7 × 109 conidia/mL) exhibited greater virulence, with eggs showing a mortality rate of 98.66%, followed by larvae 96%, adults 90.66%, and pupae 77.33% after 12 days. Probit analysis revealed minimal LC50 and LC90 values: eggs (5.5 × 102; 1.0 × 106 spores/mL), larvae (8.2 × 102; 1.2 × 107 spores/mL), pupae (9.6 × 104; 7.3 × 1010 spores/mL), and adults (1.0 × 103; 2.0 × 108 spores/mL). The total hemocyte counts and detailed observational results revealed that B. brongniartii induces cellular breakdown and cell lysis in S. litura larvae by producing enzymes that degrade the cuticle and cell membranes. Earthworm bioindicator studies showed minimal effects from B. brongniartii conidia compared to controls, while chemical treatments resulted in 96% mortality at 100 ppm. Histopathological examinations revealed no significant differences in gut tissue between earthworms treated with fungal conidia and those in the control group, unlike the substantial damage caused by chemical treatments. Biochemical analysis revealed significant alterations in enzyme activity, including reduced levels of phosphatase and catalase, as well as increased levels of lipid peroxides and superoxide dismutase. This study highlights the effectiveness of B. brongniartii in controlling S. litura, demonstrating its potential as a viable biocontrol agent and promoting eco-friendly alternatives to chemical pesticides, with no risk to non-target species or the environment

Effects of copper nanoparticles synthesized from the entomopathogen Metarhizium robertsii against the dengue vector Aedes albopictus (Skuse, 1894).

Aedes albopictus, known as the Asian tiger mosquito, is a significant vector for dengue fever, chikungunya, zika virus, yellow fever. Current control methods rely on chemical insecticides, which face challenges such as resistance, environmental harm, and impact on non-target species Eudrilus eugeniae and Artemia salina. This study evaluates the toxic effects of biogenic copper nanoparticles (CuNPs) synthesized using Metarhizium robertsii intracellular extract obtained from our previous research. The CuNPs were tested against A. albopictus and non-target species at 24 and 48 hours post-treatment. Results demonstrated that entomopathogenic fungi-derived CuNPs exhibited potent mosquitocidal activity, resulting in 97.33% mortality in larvae, 93.33% in pupae, and 74.66% in adults at 48 hours post-treatment. The CuNPs derived from M. robertsii showed lower LC50 values of 74.873 mg/L in larvae, 76.101 mg/L in pupae, and 136.645 mg/L in adults at 48 hours post-treatment. Additionally, 12 hours post-treatment, catalase (an antioxidant enzyme) activity decreased 1.5-fold in a dose-dependent manner, while glutathione S-transferase (a detoxification enzyme) activity increased 7.8-fold. CuNPs demonstrated lower toxicity to non-target species, with 24% mortality in A. salina and 24.44% mortality in E. eugeniae at 24 hours post-treatment. The LC50 values were 634.747 mg/L for A. salina and 602.494 mg/L for E. eugeniae at 24 hours post-treatment. These findings indicate that entomopathogenic fungi-derived CuNPs are a promising, target-specific candidate for controlling A. albopictus at various life stages (larvae, pupae, and adults)

Insecticidal Efficacy of Metarhizium anisopliae Derived Chemical Constituents against Disease-Vector Mosquitoes

Insecticides can cause significant harm to both terrestrial and aquatic environments. The new insecticides derived from microbial sources are a good option with no environmental consequences. Metarhizium anisopliae (mycelia) ethyl acetate extracts were tested on larvae, pupae, and adult of Anopheles stephensi (Liston, 1901), Aedes aegypti (Meigen, 1818), and Culex quinquefasciatus (Say, 1823), as well as non-target species Eudrilus eugeniae (Kinberg, 1867) and Artemia nauplii (Linnaeus, 1758) at 24 h post treatment under laboratory condition. In bioassays, Metarhizium anisopliae extracts had remarkable toxicity on all mosquito species with LC50 values, 29.631 in Ae. aegypti, 32.578 in An. stephensi and 48.003 in Cx. quinquefasciatus disease-causing mosquitoes, in A. nauplii shows (5.33–18.33 %) mortality were produced by the M. anisopliae derived crude extract. The LC50 and LC90 values were, 620.481; 6893.990 μg/mL. No behavioral changes were observed. A low lethal effect was observed in E. eugeniae treated with the fungi metabolites shows a 14.0 % mortality. The earthworm E. eugeniae mid-gut histology revealed that M. anisopliae extracts had no more harmful effects on the epidermis, circular muscle, setae, mitochondrion, and intestinal lumen tissues than chemical pesticides. By Liquid chromatography mass spectrometry (LC-MS) analysis, camphor (25.4 %), caprolactam (20.68 %), and monobutyl phthalate (19.0 %) were identified as significant components of M. anisopliae metabolites. Fourier transform infrared (FT-IR) spectral investigations revealed the presence of carboxylic acid, amides, and phenol groups, all of which could be involved in mosquito toxicity. The M. anisopliae derived chemical constituents are effective on targeted pests, pollution-free, target-specific, and are an alternative chemical insecticide

Insecticidal Efficacy of Metarhizium anisopliae Derived Chemical Constituents against Disease-Vector Mosquitoes

Insecticides can cause significant harm to both terrestrial and aquatic environments. The new insecticides derived from microbial sources are a good option with no environmental consequences. Metarhizium anisopliae (mycelia) ethyl acetate extracts were tested on larvae, pupae, and adult of Anopheles stephensi (Liston, 1901), Aedes aegypti (Meigen, 1818), and Culex quinquefasciatus (Say, 1823), as well as non-target species Eudrilus eugeniae (Kinberg, 1867) and Artemia nauplii (Linnaeus, 1758) at 24 h post treatment under laboratory condition. In bioassays, Metarhizium anisopliae extracts had remarkable toxicity on all mosquito species with LC50 values, 29.631 in Ae. aegypti, 32.578 in An. stephensi and 48.003 in Cx. quinquefasciatus disease-causing mosquitoes, in A. nauplii shows (5.33–18.33 %) mortality were produced by the M. anisopliae derived crude extract. The LC50 and LC90 values were, 620.481; 6893.990 μg/mL. No behavioral changes were observed. A low lethal effect was observed in E. eugeniae treated with the fungi metabolites shows a 14.0 % mortality. The earthworm E. eugeniae mid-gut histology revealed that M. anisopliae extracts had no more harmful effects on the epidermis, circular muscle, setae, mitochondrion, and intestinal lumen tissues than chemical pesticides. By Liquid chromatography mass spectrometry (LC-MS) analysis, camphor (25.4 %), caprolactam (20.68 %), and monobutyl phthalate (19.0 %) were identified as significant components of M. anisopliae metabolites. Fourier transform infrared (FT-IR) spectral investigations revealed the presence of carboxylic acid, amides, and phenol groups, all of which could be involved in mosquito toxicity. The M. anisopliae derived chemical constituents are effective on targeted pests, pollution-free, target-specific, and are an alternative chemical insecticide.</jats:p