Search Results (10)

Pyrethroids are chemical insecticides used on a large scale in agriculture, horticulture, and forest protection. In order to reduce their use in IPM, alternative methods of controlling insect pests are introduced, such as the use of biopesticides based on entomopathogenic fungi (EPF). Species of the Beauveria genus are characterized by a very broad spectrum of action, which is why they are often used to produce preparations based on EPF. The aim of the study was to determine the effect of different doses of tested pyrethroids on the colony growth and metabolic activity of EPF from the Beauveria genus. In vitro, the effect of three pyrethroids (deltamethrin, λ-cyhalothrin, and α-cypermethrin) added to SDA medium at a dose 10 times lower than the recommended field dose (A), the recommended field dose (B), and 10 times higher than the recommended field dose (C) on colony growth and metabolic activity of B. bassiana and B. brongniartii was tested. The research carried out showed that pyrethroid insecticides used in the experiment showed various toxic effects towards the tested EPF of the genus Beauveria. The studies conducted showed that on the 20th day of the observation, λ-cyhalothrin used in the recommended field dose limited the growth of B. bassiana to the least extent in relation to the other tested pyrethroids. However, with respect to the fungus B. brongniartii, no toxic effect of this pyrethroid was found. Based on the results obtained, it was found that λ-cyhalothrin used in the recommended field dose and 10 times lower than recommended significantly increased the metabolic activity of B. bassiana. In relation to the B. brongniartii strain, detlamethrin used in each of the tested concentrations significantly affected its viability. Full article

Entomopathogenic fungus-based biopesticides are an excellent alternative to synthetic pesticides and are widely used in insect pest control. With the transformations of the agri-food system, it is important to consider the One Health approach, which recognizes that health threats are shared at the interface between people, animals, plants, and the environment. The safety and environmental impact of fungi-based insecticides should be assessed comprehensively, taking into account not only their effects on non-target organisms and human health but also their environmental fate. This includes how these substances degrade, persist, or dissipate in soil, water, and air and their potential to bioaccumulate or leach into groundwater. Such assessments are essential to ensure that their long-term use does not pose unintended risks to ecosystems or public health. This systematic review aims to identify and analyze available studies on the potential One Health hazards associated with fungal biopesticides. A total of 134 articles were selected: 84 bioassay articles (63%), 36 case reports (27%), 10 field studies (7%), and 4 other types of studies (3%). Of these articles, 59 were studies on vertebrate animals and 65 studies on invertebrate animals, 6 studies on diverse organisms, 2 studies focused specifically on risk assessment for non-target organisms in the environment, while 2 other studies looked at the toxicological hazards associated with human exposure to the metabolites of the fungus present in air. The United States had the highest number of publications (33). Beauveria bassiana and Metarhizium anisopliae followed by the fungi Cordyceps fumosorosea (Paecilomyces fumosoroseus) and B. brongniartii were the most prevalent fungal species in the studies. This review highlights that case reports of infections in humans and other vertebrates by fungi are not related to the use of fungal biopesticides. A predominance of studies with bees was identified due to the importance of these insects as pollinators. The findings indicate that fungal biopesticides pose minimal risks when used appropriately. Nevertheless, the necessity for standardized safety assessments is emphasized. In order to ensure greater effectiveness, it is essential to develop unified protocols and bioassays with specific risk indicators aligned with the One Health approach. This includes evaluating potential effects on pollinators, vertebrate toxicity, and the environmental persistence of metabolites. In future research, the development of integrated guidelines that simultaneously consider human, animal, and environmental health is recommended. Full article

Three fungal strains were employed for the stereoselective oxidation of the cheap and commercially available substrate 2-phenylethanol, which resulted in chiral building blocks being received. The whole-cell biocatalysts were as follows: Beauveria bassiana DSM 1344, Beauveria brongniartii DSM 6651, and Rhizopus arrhizus DSM 1185. The main product of Beauveria bassiana bioconversion was 1-phenylethane-1,2-diol, obtained, depending on the form of the biocatalyst, as an R-enantiomer (e.g., 99.9%) with fresh biomass application or as a racemic mixture in cases of immobilization in agar-agar. The best and most innovative results for the synthesis of the R-enantiomer of diol were received under precisely defined conditions as a result of a scaling study conducted on an automatic batch reactor. This is a pioneering result, since, in previous studies, fresh mycelium of Aspergillus niger resulted in this product being received as the (S) enantiomer. Also, the use of Rhizopus arrhizus DSM 1185 (immobilized in polyurethane foams) presented important results, as the bioconversion of phenyl ethanol led, indeed, to the racemic mixture of 1-phenylethane-1,2-diol but was accompanied by a noticeable tyrosol synthesis, which had not been reported previously. Full article

The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae), is a destructive and voracious pest of palm species worldwide. Due to environmental and regulatory concerns, ecologically safe alternatives to synthetic chemical insecticides are needed to manage this cryptic insect species. Entomopathogenic fungi have the potential to manage this pest. The scope of management and effectiveness can be improved by direct control or horizontal transmission of entomopathogenic fungal isolates. We tested in the laboratory the virulence and pathogenicity of fifteen different entomopathogenic fungal isolates belonging to the following species: Beauveria bassiana, Metarhizium anisopliae, Beauveria brongniartii and Purpureocillium lilacinum. All fungal isolates were found virulent against larvae (14.9 ± 1.06 to 81.5 ± 1.48% mortality) and adults (5.6 ± 1.12 to 51.7 ± 1.51% mortality) at 12 d post-treatment. From a screening bioassay, five M. anisopliae (WG-08, WG-09) and B. bassiana (WG-23, WG-24, WG-25) isolates were tested for their concentration response mortality against larvae and adults after 7, 14 and 21 days (d) of treatment. Mortality was found positively correlated with concentration and time. At 21 d of treatment, WG-23 and WG-25 1 × 10⁸ conidia/mL resulted in 100% mortality against larvae while only WG-25 1 × 10⁹ conidia/mL caused 100% mortality of adults. Along with mortality, all the potential isolates have strong ovicidal effects that reduced 81.49% at 1 × 10⁸ conidia/mL. The horizontal transmission bioassay indicated that the infected adults transmitted the disease to healthy individuals. Horizontal transmission of fungi from infected to non-infected adults not only caused significant mortality but also had a serious sublethal impact on insect development and fitness including reduced number of eggs/d fecundity, egg viability and neonate survival. Isolate WG-25 reduced oviposition (0.5 eggs/d), fecundity (11.7 eggs/female), egg viability (11.6%) along with larval survival 25.9% when infected male mated with normal female. In semi-field trials, all fungal isolates reduced survival of larvae found inside the palms and ultimately reduced infestations over a period of two months. The results of this study indicate that entomopathogenic fungi should be further tested for sustainable and efficient control of RPW in date palm production systems. Full article

The aim of the study was to evaluate the potential of using five selected species of entomopathogenic fungi (Beauveria bassiana, B. brongniartii, Conidiobolus coronatus, Isaria fumosorosea, and Metarhizium robertsii) in the bioregulation of the dispersive stages of the parasitic nematode—Ascaris suum. Experimental cultures of each of the selected entomopathogenic fungi, as well as a control culture without fungi, were incubated with A. suum eggs at 26 °C for 28 days. Development of the A. suum eggs was observed using a light microscope on the 7th, 14th, 21st, and 28th days of incubation. The API-ZYM^® test was used to determine, semiquantitatively, the activity of 19 hydrolytic enzymes from the entomopathogenic fungi. The cytotoxicity of the fungi was determined using tetrazole salt MTT. It was found that none of the five tested strains of entomopathogenic fungi showed an ovicidal effect, and none of them colonized the A. suum egg shells. However, ovistatic activity was observed mainly until the 14th day of incubation by I. fumosorosea, M. robertsii, and B. bassiana. In the MTT test, M. robertsii showed moderate cytotoxicity, while the other species showed low cytotoxicity. Among the strains tested, I. fumosorosea showed the highest spectrum of hydrolase production (13 out of 19 enzymes gave a positive reaction from 3 to 5; 20–40 nM or more). The absence of morphological changes in the A. suum egg shells suggests that the antagonistic effect of the studied entomopathogenic fungi may be due to their cytotoxicity, associated with the production of secondary metabolites—toxins (M. robertsii) and enzymatic activity (I. fumosorosea). Full article

The gut bacterial microbiota of insects plays a crucial role in physiological, metabolic, and innate immune processes. In the current study, the gut bacterial communities of an insecticide-susceptible (IS), and a resistant (IR) population of a major legume pest, Megalurothrips usitatus (Bagnall), were evaluated. The 16S rDNA V3 + V4 regions of M. usitatus infected with Beauveria brongniartii along with the intestinal flora of both populations were sequenced based on a High-throughput sequencing platform. Toxicological bioassays revealed that the IR population exhibited resistance to acetamiprid and B. brongniartii isolate SB010 at levels of 138.0-fold and 55.6-fold higher, respectively, compared to the IS population. Through 16S High-throughput sequencing, the results indicate that both resistant populations, as well as B. brongniartii infestation, reduce the number of species of M. usitatus gut microbes. Using KEGG function prediction, it was found that most intestinal bacteria were involved in various metabolic activities, and the abundance of resistant populations was higher than that of sensitive populations. The bacteria in the gut of M. usitatus are mainly involved in various metabolic activities to achieve the degradation of B. brongniartii. This study provides valuable insights into the interaction between gut bacteria, insecticide resistance, and Beauveria. brongniartii infection in Megalurothrips usitatus, which can help inform future pest control strategies. Full article

The white-spotted longicorn beetle, Anoplophora malasiaca, is one of the most destructive pests of horticultural crops and street trees. Effective controls are needed because the effect of marketed insecticides is limited. Entomopathogenic fungi offer a solution, and improving the rate of infection would be a breakthrough in this beetle’s control. The combination of pathogenic fungi and the beetle’s contact sex pheromone was suggested. The surface of the female body is covered with contact sex pheromone, which elicit male mating behavior. To develop a method for the practical control of this beetle, we evaluated the arrestant activity of female extract containing contact pheromone coated on a black glass model. Males presented with a coated model held on for 5 h (mean) during an 8-h experiment. In contrast, males presented with a control model held on for <0.3 h. Males that held onto coated models attached to fabric impregnated with conidia of the fungus Beauveria brongniartii picked up much conidia, which they then passed on to females during mating. Full article

The efficacy of two strains of two Beauveria species (B. bassiana and B. brongniartii), individually or as co-inoculants, to control Melolontha sp. grubs was assessed in two organic strawberry plantations in relation to the environmental conditions, their abundance after soil inoculation, and their in vitro chitinolytic activity, thereby also verifying their impact on soil microbial communities. A reduction of the grubs’ damage to strawberry plants was observed when compared to the untreated control in one plantation, irrespective of the strain used and whether they were applied as single or as co-inoculum. The metabolic pattern expressed by the two fungi in vitro was different: B. bassiana showed a higher metabolic versatility in the use of different carbon sources than B. brongniartii, whose profile was partly overlapped in the co-inoculum. Similar differences in the chitinolytic activity of each of the fungi and the co-inoculum were also pointed out. A higher abundance of B. bassiana in the soils receiving this species in comparison to those receiving B. brongniartii, together with its in vitro metabolic activity, could account for the observed diverse efficacy of pest damage control of the two species. However, environmental and climatic factors also affected the overall efficacy of the two bioinocula. According to the monitoring of the two species in soil, B. bassiana could be considered as a common native species in the studied locations in contrast to B. brongniartii, which seemed to be a non-endemic species. Nevertheless, the inoculation with both species or the co-inoculum did not consistently affect the soil microbial (fungi and bacteria) biodiversity, as expressed by the operational taxonomic unit (OTU) number and Shannon–Wiener diversity index based on terminal restriction fragment length polymorphism (TRFLP) data. A small transient increase of the share of the inoculated species to the total fungal community was noted by the analysis of genes copy numbers only for B. brongniartii at the end of the third growing season. Full article

Nanotechnology has clear potential in the development of innovative insecticidal products for the biorational management of major insect pests. Metal-based nanoparticles of different microbial pest control agents have been effective against several pests. Synthesis of Beauveria brongniartii based Fe⁰ nanoparticles (Fe⁰NPs) and their bio-efficacy against Spodoptera litura was observed during this study. Beauveria brongniartii conidia were coated with Fe⁰NPs and characterized by applying a selection of different analytical techniques. Ultraviolet (UV) spectroscopy showed the characteristic band of surface plasmon at 430 nm; Scanning electron microscopy (SEM) images showed spherical shaped nanoparticles with a size ranging between 0.41 to 0.80 µm; Energy-dispersive X-ray (EDX) spectral analysis revealed characteristic Fe peaks at 6.5 and 7.1 Kev; the X-ray diffractogram showed three strong peaks at 2θ values of 45.72°, 64.47°, and 84.05°. The bioassay studies demonstrated that mortality of 2nd instar S. litura larvae following Fe⁰NPs treatment increased with increasing concentrations of Fe⁰NPs at different time intervals. The median lethal concentration (LC₅₀) values of Fe⁰NPs against S. litura after seven days of fungal treatment was 59 ppm, whereas median survival time (LT₅₀) values for 200 and 500 ppm concentrations of Fe⁰NPs against S. litura seven days post-treatment were 5.1 and 2.29 days, respectively. Beauveria brongniartii-Fe⁰NPs caused significant reductions in feeding and growth parameters (relative growth rate, relative consumption rate, and efficiency of conversion of ingested food) of S. litura. Beauveria brongniartii Fe⁰NPs induced reduction in glutathione-S-transferase activities throughout the infection period whereas activities of antioxidant enzymes decreased during later periods of infection. These findings suggest that B. brongniartii Fe⁰NPs can potentially be used in biorational S. litura management programs. Full article

Microbial biopesticides include several microorganisms like bacteria, fungi, baculoviruses, and nematode-associated bacteria acting against invertebrate pests in agro-ecosystems. The biopesticide sector is experiencing a significant growth and many discoveries are being developed into new biopesticidal products that are fueling a growing global market offer. Following a few decades of successful use of the entomopathogenic bacterium Bacillus thuringiensis and a few other microbial species, recent academic and industrial efforts have led to the discovery of new microbial species and strains, and of their specific toxins and virulence factors. Many of these have, therefore, been developed into commercial products. Bacterial entomopathogens include several Bacillaceae, Serratia, Pseudomonas, Yersinia, Burkholderia, Chromobacterium, Streptomyces, and Saccharopolyspora species, while fungi comprise different strains of Beauveria bassiana, B. brongniartii, Metarhizium anisopliae, Verticillium, Lecanicillium, Hirsutella, Paecilomyces, and Isaria species. Baculoviruses are species-specific and refer to niche products active against chewing insects, especially Lepidopteran caterpillars. Entomopathogenic nematodes (EPNs) mainly include species in the genera Heterorhabditis and Steinernema associated with mutualistic symbiotic bacteria belonging to the genera Photorhabdus and Xenorhabdus. An updated representation of the current knowledge on microbial biopesticides and of the availability of active substances that can be used in integrated pest management programs in agro-ecosystems is reported here. Full article