Toxicity and Biological Effects of Beauveria brongniartii Fe0 Nanoparticles against Spodoptera litura (Fabricius)

Entomopathogenic Fungi: An Eco-Friendly Synthesis of Sustainable Nanoparticles and Their Nanopesticide Properties

The agricultural industry could undergo significant changes due to the revolutionary potential of nanotechnology. Nanotechnology has a broad range of possible applications and advantages, including insect pest management using treatments based on nanoparticle insecticides. Conventional techniques, such as integrated pest management, are inadequate, and using chemical pesticides has negative consequences. As a result, nanotechnology would provide ecologically beneficial and effective alternatives for insect pest control. Considering the remarkable traits they exhibit, silver nanoparticles (AgNPs) are recognized as potential prospects in agriculture. Due to their efficiency and great biocompatibility, the utilization of biologically synthesized nanosilver in insect pest control has significantly increased nowadays. Silver nanoparticles have been produced using a wide range of microbes and plants, which is considered an environmentally friendly method. However, among all, entomopathogenic fungi (EPF) have the most potential to be used in the biosynthesis of silver nanoparticles with a variety of properties. Therefore, in this review, different ways to get rid of agricultural pests have been discussed, with a focus on the importance and growing popularity of biosynthesized nanosilver, especially silver nanoparticles made from fungi that kill insects. Finally, the review highlights the need for further studies so that the efficiency of bio-nanosilver could be tested for field application and the exact mode of action of silver nanoparticles against pests can be elucidated, which will eventually be a boon to the agricultural industry for putting a check on pest populations.

Synergism and toxicity of iron nanoparticles derived from Trigonella foenum-graecum against pyrethriod treatment in S. litura and H. armigera (Lepidoptera: Noctuidae)

The tobacco cutworm, Spodoptera litura and cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae) are important pests of various agricultural crops that cause sevier economic loses throughout the world. Indiscriminate and frequent use of insecticide may lead to development of resistance in these pests. Nanotechnology has given an alternative to manage and overcome insecticide resistance for pest management strategies. In the present study the iron nanoparticles derived from Trigonella foenum-graecum leaf extract (FeNPs) was investigated for its ecofriendly management of pyrethroid resistance in two lepidopteron pest species at 24 h, 48 h and 72 h post treatment. The result showed high mortality (92.83% and 91.41%) of S. litura and H. armigera at 72 h treatment upon FeNPs and fenvalerate (Fen + FeNPs) teratment. Probit analysis revealed high LC₅₀ upon Fen + FeNPs treatment (130.31 and 89.32 mg/L) with a synergism ratio of 1.38 and 1.36. Antifeedant activity of six dofferent concentration of FeNPs revelaed increased antifeedant activity with respect to increasing concentration of nanoparticles ranging from 10 to 90% and 20-95% againt both insects (p<0.05). Detoxification activity of carboxylesterase was elevated at 630 μmol/mg protein/min (p<0.05) in fenvalerate treatment, whereas decreased activity was found (392umole/mg protein/min) in FeNPs and Fen + FeNPs treatment (P<0.001). GST and P450 activity was also increased in fenvalerate treatment, whereas decreased activity was observed in FeNPs and Fen + FeNPs. Esterase isoenzyme banding pattern revealed four bands in fenvalerate treatment and two bans (E3 and E4) in Fen + FeNPs combination. Hence the present study concludes that T. foenum-graecum synthesized iron nanoparticles could be an effective alternate for ecofriendly management of S. litura and H. armigera.

Insecticidal efficacy of nanoparticles against Spodoptera frugiperda (J.E. Smith) larvae and their impact in the soil

The present study aims to evaluate the different nanoparticles (Cu NPs, KI NPs, Ag NPs, Bd NPs, and Gv NPs) against 4th instar Spodoptera frugiperda larvae as well as the microbial toxicity, phytotoxicity, and soil pH. Nanoparticles were tested at three concentrations (1000, 10000, and 100000 ppm) using two methods (food dip and larvae dip) against S. frugiperda larvae. Results (from the larval dip method) showed that among the nanoparticles, the KI NPs caused 63%, 98%, and 98% mortality within 5 days in the treatment of 1000, 10000, and 100000 ppm, respectively. After 24 h post treatment, a 1000 ppm concentration showed 95%, 54%, and 94% germination rates in Metarhizium anisopliae, Beauveria bassiana, and Trichoderma harzianum, respectively. The phytotoxicity evaluation clearly showed that NPs did not affect the morphology of the corn plants after the treatment. The soil nutrient analysis results showed that no effect was observed in soil pH or soil nutrients compared to control treatments. The study clearly showed that nanoparticles are caused toxic effect against S. frugiperda larvae.

Prospective of mycorrhiza and Beauvaria bassiana silica nanoparticles on Gossypium hirsutum L. plants as biocontrol agent against cotton leafworm, Spodoptera littoralis

BACKGROUND

Plant-herbivorous insects are a severe danger to the world's agricultural production of various crops. Insecticides used indiscriminately resulted in habitat destruction due to their high toxicity, as well as disease resistance. In this respect, the development of a sustainable approach to supreme crop production with the least damage is a crucially prerequisite. As a result, the current study was carried out to understand the potential effect of arbuscular mycorrhizal (AM) fungi along with Beauvaria bassiana silica nanoparticles (Si NPs) as a new approach to increase cotton (Gossypium hirsutum L. Merr.) defense against an insect herbivore, Spodoptera littoralis. AM and non-AM cotton plants were infested with S. littoralis and then sprayed with a biopesticide [B. bassiana Si NPs] or a chemical insecticide (Chlorpyrifos).

RESULTS

The gas chromatography-mass spectrometry (GC-MS) analysis of B. bassiana Si NPs fungal extract showed that the major constituents identified were Oleyl alcohol, trifluoroacetate, 11-Dodecen-1-AL and 13-Octadecenal, (Z)-(CAS). Besides, results revealed a highly significant decrease in growth parameters in S. littoralis infested plants, however, with AM fungal inoculation a substantial improvement in growth traits and biochemical parameters such as protein and carbohydrates contents was observed. In addition, stimulation in proline and antioxidant enzymes activity and a decrease in malondialdehyde content were observed after AM inoculation.

CONCLUSION

AM fungi mitigate the harmful effects of herbivorous insects by strengthening the cotton plant's health via enhancing both morphological and biochemical traits that can partially or completely replace the application of chemical insecticides.

The Effect of Silicon Dioxide Nanoparticles Combined with Entomopathogenic Bacteria or Fungus on the Survival of Colorado Potato Beetle and Cabbage Beetles

Three types of modified silicon dioxide nanoparticles (SiO2, 10−20 nm) with additives of epoxy, silane and amino groups, used independently and in combination with the entomopathogenic bacteria Bacillus thuringiensis subsp. morrisoni and fungus Metarhizium robertsii were tested against Colorado potato beetle (Leptinotarsa decemlineata) and cabbage beetles (Phyllotreta spp.). All three nanoparticles were found to have an entomocidal effect on Colorado potato beetle larvae and crucifer flea beetles when ingested. Increased susceptibility of insects to B. thuringiensis or M. robertsii blastospores and their metabolites was shown after exposure to the modified silicon dioxide nanoparticles. The potential of modified silicon dioxide nanoparticles to enhance the efficiency of biopesticides based on the bacteria B. thuringiensis and fungi M. robertsii is considered in the paper.

Synthesis of Metarhizium anisopliae–Chitosan Nanoparticles and Their Pathogenicity against Plutella xylostella (Linnaeus)

Nanotechnology is increasingly being used in areas of pesticide production and pest management. This study reports the isolation and virulence of a new Metarhizium anisopliae isolate SM036, along with the synthesis and characterization of M. anisopliae–chitosan nanoparticles followed by studies on the efficacy of nanoparticles against Plutella xylostella. The newly identified strain proved pathogenic to P. xylostella under laboratory conditions. The characterization of M. anisopliae–chitosan nanoparticles through different analytical techniques showed the successful synthesis of nanoparticles. SEM and HRTEM images confirmed the synthesis of spherical-shaped nanoparticles; X-ray diffractogram showed strong peaks between 2θ values of 16–30°; and atomic force microscopy (AFM) analysis revealed a particle size of 75.83 nm for M. anisopliae–chitosan nanoparticles, respectively. The bioassay studies demonstrated that different concentrations of M. anisopliae–chitosan nanoparticles were highly effective against second instar P. xylostella under laboratory and semi-field conditions. These findings suggest that M. anisopliae–chitosan nanoparticles can potentially be used in biorational P. xylostella management programs.

Synthesis of Cordyceps fumosorosea-Biochar Nanoparticles and Their Effects on Growth and Survival of Bemisia tabaci (Gennadius)

Nanotechnology can offer an environmentally sustainable alternative to synthetic chemicals for pest management. Nano-formulations of different microbial pest control agents have been effective against several insect pests. Synthesis of Cordyceps fumosorosea-biochar (BC) nanoparticles and their bio-efficacy against Bemisia tabaci was observed during this study. The characterization of C. fumosorosea-BC nanoparticles through different analytical techniques showed successful synthesis of nanoparticles. UV spectroscopy showed a characteristic band of surface plasmon between 350 and 400 nm; SEM images confirmed the synthesis of spherical shaped nanoparticles; X-ray diffractogram showed strong peaks between 2θ values of 20°–25°; and atomic force microscopy (AFM) analysis revealed particle size of 49.151 nm. The bioassay studies demonstrated that different concentrations of C. fumosorosea-BC nanoparticles caused significant reduction in hatchability of B. tabaci eggs as well as survival of immatures emerging from treated eggs when compared with controls. The results also revealed that C. fumosorosea-BC nanoparticles were highly pathogenic against 2nd and 3rd instar nymphs and pupae of B. tabaci having LC₅₀ values of 6.80, 7.45, and 8.64 ppm, respectively. The LT₅₀ values for 20 ppm concentration of C. fumosorosea-BC nanoparticles against 2nd and 3rd instar nymphs, and pupae of B. tabaci were 3.25 ± 0.29, 3.69 ± 0.52, and 4.07 ± 0.51 days, respectively. These findings suggest that C. fumosorosea-BC nanoparticles can potentially be used in biorational B. tabaci management programs.