Development Of Bioinsecticides Research Articles

Direct and delayed effect of the plant Cleome amblyocarpa Barratte & Murb (Capparidaceae) on the two species of (Blattodea) Blattella germanica (Linnaeus, 1767) and Shelfordella lateralis (Walker, 1868)

Finding substantial substitution of chemical pesticides to control cockroaches, which were proved to have a link with multiple health issues, has become the major target of many researchers. In fact, subjecting this pest to the effects of toxic plants extracts is considered ideal to primarily avoid jeopardizing human health. This study is divided into two objectives. The first of which is to confirm the toxicity of the ethanoic extract from the Cleome arabica plant on two species of urban cockroaches; which are Bllattella germanica and Bllatta lateralis, while the second is to verify the effect of the attractive odor of the extract on the feeding behavior of the two already mentioned species. Therefore, the findings demonstrated that, on the one hand, the extract causes a mortality rate of 60% of B. germanica after 30 days of treatment at a high concentration of (3g/l). On the other hand, mortality rate in B. lateralis does not exceed 6.7%. Further, findings exhibited that the proportion of B. germanica attracted by the smell of the plant soaked in hexane at a specified time (15, 30 and 60 minutes) was estimated at 40%, whereas that of B. lateralis exceeded 60%. The results of this work suggest the presence of toxic substances in the studied extract which may lead to the development of bio-insecticides based on Cleome arabica to be used in the pesticide market.

Effect of microencapsulated/photoresistant extract of Azadirachta indica A. Juss seeds on Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctudae) and its persistence in semi-field

The development of bioinsecticides as an alternative to synthetic insecticides can benefit the economy of exporting and importing countries, family farming, production of high-quality commodities, food security, quality of life, and the natural environment. This study aimed to evaluate the effect of microencapsulated extracts of Azadirachta indica A. Juss on Spodoptera frugiperda J.E. Smith and their persistence in the plant under semi-field conditions. The fresh seeds of A. indica, collected in Brazil, were separated for the preparation of the microencapsulated dry extract (MDE) according to criteria registered in the patent. Lethal concentrations for S. frugiperda were determined using a dose response curve. The treatments were compared: MDE, control and positive control based on azadirachtin, evaluating mortality and growth inhibition. There was a significant difference in mortality between the treatments tested. The lethal concentrations LC50 and LC95, expressed in azadirachtin for the bioinsecticide, were 194.98 and 630.95 ppm, respectively. The growth inhibition of S. frugiperda was above 98 % in the treatments, except for the control. The MDE presented lethal times LT50 and LT90 lower than the other treatments (lethal time LT50 = 2.79 d; lethal time LT90 = 3.97 d). The MDE of A. indica seeds was effective in controlling S. frugiperda up to the fifth instar and is considered as slightly persistent to persistent depending on environmental conditions and irrigation, based on IOBC/WPRS parameters. The MDE has the potential to be a phytosanitary product approved for use in organic agriculture and with greater effectiveness in controlling S. frugiperda compared to similar pesticides.Abbreviations: BOD, Biochemical Oxygen Demand; CPA, commercial product based on azadirachtin; CLE, concentrated liquid extract; DAS, days after spraying; GI, growth inhibition; LC50, lethal concentration for 50% of the population; LC95, lethal concentration for 95% of the population; LT50, lethal time for 50% of the population; LT90, lethal time for 90% of the population; MDE, microencapsulated dry extract.

Microbiota diversity and anti-Pseudogymnoascus destructans bacteria isolated from Myotis pilosus skin during late hibernation.

Symbiotic microorganisms that reside on the host skin serve as the primary defense against pathogens in vertebrates. Specifically, the skin microbiome of bats may play a crucial role in providing resistance against Pseudogymnoascus destructans (Pd), the pathogen causing white-nose syndrome. However, the epidermis symbiotic microbiome and its specific role in resisting Pd in highly resistant bats in Asia are still not well understood. In this study, we collected and characterized skin microbiota samples of 19 Myotis pilosus in China and explored the differences between Pd-positive and negative individuals. We identified inhibitory effects of these bacteria through cultivation methods. Our results revealed that the Simpson diversity index of the skin microbiota for positive individuals was significantly lower than that of negative individuals, and the relative abundance of Pseudomonas was significantly higher in positive bats. Regardless of whether individuals were positive or negative for Pd, the relative abundance of potentially antifungal genera in skin microbiota was high. Moreover, we successfully isolated 165 microbes from bat skin and 41 isolates from positive individuals able to inhibit Pd growth compared to only 12 isolates from negative individuals. A total of 10 genera of Pd-inhibiting bacteria were screened, among which the genera Algoriella, Glutamicibacter, and Psychrobacter were newly discovered as Pd-inhibiting genera. These Pd-inhibiting bacteria metabolized a variety of volatile compounds, including dimethyl trisulfide, dimethyl disulfide, propylene sulfide, 2-undecanone, and 2-nonanone, which were able to completely inhibit Pd growth at low concentrations.IMPORTANCERecently, white-nose syndrome has caused the deaths of millions of hibernating bats, even threatening some with regional extinction. Bats in China with high resistance to Pseudogymnoascus destructans can provide a powerful reference for studying the management of white-nose syndrome and understanding the bats against the pathogen's intrinsic mechanisms. This study sheds light on the crucial role of host symbiotic skin microorganisms in resistance to pathogenic fungi and highlights the potential for harnessing natural defense mechanisms for the prevention and treatment of white-nose syndrome. In addition, this may also provide promising candidates for the development of bioinsecticides and fungicides that offer new avenues for addressing fungal diseases in wildlife and agricultural environments.

Development of bioinsecticide based on Streptomyces griseoflavus PAL114 for control of black bean aphids Aphis fabae

ABSTRACT This research highlights the efficiency of a bioinsecticide based on Streptomyces griseoflavus PAL114 in controlling black bean aphids and its effect on fava beans. Three actinobacterial strains were tested in vitro for their aphicidal activity. The PAL114 strain was then formulated in talc powder and tested again. Formulation processes were performed with four spore suspension densities (102, 104, 106 and 108 spore ml−1) at a rate of 25 ml per 100 g of talc powder. Furthermore, the in vivo effect of bioinsecticide on fava bean plants was studied in pot experiments using two application methods: spray and spray + soil amendment. The results showed that only the PAL114 strain had a highly significant effect on mortality (p = .001). Their high-density formulations at 106 and 108 spore ml−1 induced very highly significant activity (p < .001) for both, with no influence difference exceeding 90% after 58 h. In contrast, the other low-density formulations at 102 and 104 spore ml−1 had no significant effect (p = .322 and p = 1.000, respectively). There was no adverse effect of the bioinsecticide on fava bean; instead, there was an improvement in growth, especially when the spray application was combined with soil amendment. The present study opens up prospects for field studies on the biocontrol of this crop pest.

Prediction Prediction of the Insecticidal Potency of Biduri Plants (Calotropis gigantea) using the PASS online web resource

Calotropis gigantea, a wild plant thriving in arid environments, has been traditionally used for medicinal purposes by communities near Baluran National Park (BNP). The latex of C. gigantea is used as a crab poison due to its ability to cause fatal damage and separation of body parts, possibly related to chitin disruption in insects. This study explores the potential insecticidal properties of secondary metabolites in C. gigantea using Prediction of Activity Spectra for Substance (PASS) Online. Out of 68 identified secondary metabolites, six show significant insecticidal potential, namely Profenophos, Ethion, Alpha-Citral, 1-Phenylethyl acetate, (E)-dec-3-en-2-one, and Benzaldehyde. Notably, Profenophos, Ethion, Alpha-Citral, and Benzaldehyde exhibit toxic properties effective against insects, with enzyme inhibitory activity affecting nerve signaling and immune systems, suggesting potential for bio-insecticide development.

CHEMICAL COMPOSITION AND INSECTICIDAL EFFICACY OF VITEX NEGUNDO L. ESSENTIAL OIL AGAINST FALL ARMYWORM, SPODOPTERA FRUGIPERDA (J. E. SMITH)

The fall armyworm, Spodoptera frugiperda, is a key pest ofmaize crops in tropical and subtropical regions and has developed resistanceagainst synthetic pesticides and Bacillus thuringiensis toxins. Thus,the experiments were designed to evaluate the chemical analysis andinsecticidal efficacy of Vitex negundo against S. frugiperda.Chemical analysis of V. negundo essential oil revealed a total of 36compounds, and the oil contained more monoterpenes (68.16%) than sesquiterpenes(22.21%) and diterpenes (13.56%). For the ovicidal and insecticidal activities,the essential oil was found to be most effective, with a median lethalconcentration (LC50) value of 51.31 µL/mL and 0.29 L/larvae, respectively.Larval antifeedant and growth inhibitory activity of essential oil werepositively correlated (R2 = 0.9645) and (R2 = 0.9727) with oil concentrations,respectively. Therefore, the V. negundo essential oil can be used forthe development of bioinsecticides to control S. frugiperda, a highlyinvasive and polyphagous pest, which will replace chemical pesticides.

Evaluation f the Insecticidal Activity of Nerium Oleander and Artemisia Campestris Powder and Extract on Wheat Insect Pests

Objective: The study aimed to evaluate the insecticidal potential of powders and methanolic extracts of two plants of the Lamiaceae and Apocynaceae families spontaneously growing in the region of Tiaret. Method: Insecticide tests were carried out in the laboratory using the Direct Contact Method. Results and Discussion: The obtained results showed that Nerium oleander and Artemisia campestris powders have remarkable insecticidal properties. N oleander powders induced 100% mortality in adults and up to 80% mortality in Tribolium castaneum larvae at a dose of 0.5g, after 7 days of exposure. Adults of Tribolium confusum showed some resistance to the powders of both plants, with an optimum mortality rate equal to 50% for adults. Larvae of both species were found to be sensitive to N. oleander powder with a mortality rate ranging from80to 90%. As for the powder of A. campestris, adults of T. castaneum were more sensitive than those of T.confusum, with adults’mortality rate equal to 100%. The methanolic extracts of both plants showed a very remarkable efficacy against the larvae of both species as well as the adults of T. castaneum with a mortality rate equal to 100%, after 7 days of treatment at different concentrations. Research Implications: Algeria has an abundance and diversity of flora that could provide new sources of compounds of plant origin with phytopharmaceutical properties, these results allow us to affirm that powders and methanolic extracts, of the studied plants, can be used for industrial application in the production of bio-insecticides. Originality/Value: This work could provide alternative or complementary solutions to the use of synthetic organic pesticides to protect stored beans. The development of bio-insecticides derived from plant extracts and the selection of varieties resistant to this pest are part of sustainable agriculture and development.

Insecticidal action of mammalian galectin-1-transfected Arabidopsis thaliana.

Galectins (GALs) are a family of mammalian sugar-binding proteins specific for β-galactosides. Our previous studies have shown that the larval development of the diamondback moth (Plutella xylostella) is significantly disturbed when fed with recombinant mammalian galectin 1 (GAL1) derived from Escherichia coli. To further explore its applicability, two GAL1-overexpressed Arabidopsis [GAL1-Arabidopsis (whole plant) and GAL1-Arabidopsis-vas (vascular bundle-specific)] lines were established for insecticidal activity and mechanism studies. The expression level of GAL1 in transgenic Arabidopsis is 1-0.5% (GAL1-Arabidopsis) and 0.08-0.01% (GAL1-Arabidopsis-vas) of total leaf soluble protein. Survival, body weight, and food consumption significantly decreased in a time-dependent manner in P. xylostella larvae (with chewing mouthparts) fed on GAL1-Arabidopsis. The mortality of Kolla paulula (with piercing-sucking mouthparts and xylem feeder) fed on GAL1-Arabidopsis-vas was also significantly higher than that fed on wild-type Arabidopsis (WT-Arabidopsis), but was lower than that fed on GAL1-Arabidopsis. The histochemical structure and results of immunostaining suggested that the binding of GAL1 to the midgut epithelium of P. xylostella fed on GAL1-Arabidopsis was dose- and time-dependent. Ultrastructural studies further showed the disruption of microvilli, abnormalities in epithelial cells, and fragments of the peritrophic membrane (PM) in P. xylostella larvae fed on GAL1-Arabidopsis. The insecticidal mechanism of GAL1 involves interference with PM integrity and suggests that GAL1 is a potential candidate for bioinsecticide development. © 2024 Society of Chemical Industry.

Vicia sativa subsp. sativa native to the Middle East comprises Pea Albumin1 b-like homologs: A promising natural biopesticide

The extensive and indiscriminate use of chemical pesticides in agriculture has led to adverse effects on human health, environmental pollution, and the emergence of pesticide-resistant pests. To mitigate these challenges, the development of environmentally friendly alternatives is crucial, with biopesticides emerging as promising solutions such as peptides. Legume seeds naturally contain diverse insecticidal peptides or proteins to combat pest attacks. One such peptide is PA1b (Pea Albumin 1, subunit b), a 37 amino acid extracted from pea seeds (Pisum sativum). PA1b has shown significant potential in controlling cereal weevils (Sitophilus spp.), a major pest of stored cereals. Here, we screened PA1b-like peptides in five wild seeds of vetches (Vicia sativa subsp. sativa) from the Middle East. Using a comprehensive set of biochemical, biological, and molecular techniques, we characterized different PA1b homologs and assessed their toxicity and expression profiles. Our results reveal that PA1b homolog from Vicia sativa subsp. sativa originating from turkey displays outstanding insecticidal activity against Sitophilus oryzae through binding to the receptor site found in the midgut of the insect. Moreover, it exhibits a strong cytotoxic effect against Sf9 cells. This cysteine-rich peptide shows sequence identity and the same hydrophobic pole as AG41, a tenfold more toxic isoform of PA1b from Medicago truncatula. Such observations pave the way for the development of bioinsecticides, with PA1b-like peptides as lead compounds.

Mosquito Larvicidal Activity and Cytotoxicity of the Extracts of Aromatic Plants from Malaysia.

Despite ongoing control efforts, the mosquito population and diseases vectored by them continue to thrive worldwide, causing major health concerns. There has been growing interest in the use of botanicals as alternatives to insecticides due to their widespread insecticidal properties, biodegradability, and adaptability to ecological conditions. In this study, we investigated the larvicidal activity and cytotoxicity effects of solvent extracts from three aromatic plants-Curcuma longa (turmeric), Ocimum americanum (hoary basil), and Petroselinum crispum (parsley)-against Aedes albopictus. Subsequently, we examined the phytochemical composition of the extracts through gas chromatography-mass spectrometry (GC-MS) analysis. Results revealed that the hexane extracts of O. americanum and P. crispum exhibited the greatest larvicidal activity with the lowest median lethal concentration (LC50) values (<30 µg/mL) at 24 h post-treatment, with the former found to be significantly less toxic towards African monkey kidney (Vero) cells. The GC-MS analysis of the said extract indicated the presence of different classes of metabolites, including phenylpropanoids, very long-chain alkanes, fatty acids and their derivatives, and terpenes, with the most abundant component being methyl eugenol (55.28%), most of which, have been documented for their larvicidal activities. These findings provide valuable insights into the potential use and development of bioinsecticides, particularly from O. americanum.

Tolerance to UV-B radiation of the entomopathogenic fungus Metarhizium rileyi

Soybean, corn, and cotton crops are afflicted by several noctuid pests and the development of bioinsecticides could help control these pests. The fungus Metarhizium rileyi has the greatest potential because its epizootics decimate caterpillar populations in the absence of insecticide applications. However, insect-pathogenic fungi when used for insect control in agriculture have low survival mainly due to the deleterious effects of ultraviolet radiation and heat from solar radiation. In this study, fourteen isolates of M. rileyi were studied and compared with isolates ARSEF 324 and ARSEF 2575 of Metarhizium acridum and Metarhizium robertsii, respectively, whose sensitivity to UV-B radiation had previously been studied. Conidia were exposed at room temperature (ca. 26 °C) to 847.90 mWm−2 of Quaite-weighted UV-B using two fluorescent lamps. The plates containing the conidial suspensions were irradiated for 1, 2, and 3 h, providing doses of 3.05, 6.10, and 9.16 kJ m2, respectively. A wide variability in conidial UV-B tolerance was found among the fourteen isolates of M. rileyi. Isolate CNPSo-Mr 150 was the most tolerant isolate (germination above 80% after 2 h exposure), which was comparable to ARSEF 324 (germination above 90% after 2 h exposure), the most tolerant Metarhizium species. The least tolerant isolates were CNPSo-Mr 141, CNPSo-Mr 142, CNPSo-Mr 156, and CNPSo-Mr 597. Nine M. rileyi isolates exhibited similar tolerance to UV-B radiation as ARSEF 2575 (germination above 50% after 2 h exposure). In conclusion, the majority of M. rileyi isolates studied can endure 1 or 2 h of UV-B radiation exposure. However, after 3 h of exposure, the germination of all studied isolates reduced below 40%, except for CNPSo-Mr 150 and ARSEF 324.

Residues of Legume AG41 Peptide Crucial to Its Bio-Insecticidal Activity

Currently, crop protection relies heavily on chemical treatments, which ultimately leads to environmental contamination and pest resistance. Societal and public policy considerations urge the need for new eco-friendly solutions. In this perspective, biopesticides are effective alternatives to chemical insecticides for the control of various insect pests. Legumes contain numerous insecticidal proteins aimed at protecting their high nitrogen content from animal/insect predation. Investigating one such protein family at genome scale, we discovered a unique diversity of the albumin 1 family in the (model) barrel medic genome. Only some members retained very high insecticidal activity. We uncovered that AG41 peptide from the alfalfa roots displays an outstanding insecticidal activity against several pests such as aphids and weevils. Here we report the 3D structure and activity of AG41 peptide. Significant insights into the structural/functional relationships explained AG41 high insecticidal activity. Such observations pave the way for the development of bio-insecticides, with AG41 peptide as the lead compound.

A Review of the Chemistry and Biological Activities of Acmella oleracea ("jambù", Asteraceae), with a View to the Development of Bioinsecticides and Acaricides.

Human pathologies, environmental pollution, and resistance phenomena caused by the intensive use of chemical pesticides have shifted the attention of the agrochemical industries towards eco-friendly insecticides and acaricides. Acmella oleracea (L.) R. K. Jansen (jambù) is a plant native to South America, widely distributed and cultivated in many countries due to its numerous pharmacological properties. This review analyzes literature about the plant, its uses, and current knowledge regarding insecticidal and acaricidal activity. Acmella oleracea has proven to be a potential pesticide candidate against several key arthropod pest and vector species. This property is inherent to its essential oil and plant extract, which contain spilanthol, the main representative of N-alkylamides. As a result, there is a scientific basis for the industrial exploitation of jambù in the preparation of green insecticides. However, studies related to its toxicity towards non-target species and those aimed at formulating and developing marketable products are lacking.

DEVELOPMENT OF BIOINSECTICIDES AGAINST SPODOPTERA FRUGIPERDA USING CHITINOLYTIC BACTERIA

Actinomycetes play an important role in the biological control of insects by producing insecticidal active compounds against various insects. They are predominantly found in soil, in the silt of water bodies, in the air and in plant remains. Chitinase is increasingly finding applications in various fields such as biomedicine, in ultra-structural studies, in the preparation of chitooligosaccharides, in single-cell protein production, biocontrol agents, agriculture, etc. Chitinase is originally an enzyme used by insects to degrade the structural polysaccharide of insects. Chitinase brings about hydrolysis of chitin which is widely distributed in cell wall of fungi, plants and insects. An attempt has been made to use chitinase producing bacteria for the development of bioinsecticides against Spodoptera frugiperda, which feeds on over more than 60 species of plants and it is periodic. The Spodoptera frugiperda armyworm (Lepidoptera) is a serious pest of cabbage and other crop. It is also major pest of maize, rice, sorghum, turf grasses, cotton, and peanuts, etc. In this attempt enrichment and isolation of chitinase producing bacteria from soil was carried out. Chitinolytic activities of the three isolates were tested against larvae of Spodoptera frugiperda. Three isolates were individually applied against Spodoptera frugiperda. The isolates named Ai, A2 and A3 were found to be more effective against Spodoptera frugiperda. The insecticidal activity of isolate A1was tested and control within 5 hours. Isolate A2 was treated with larvae Spodoptera frugiperda killed after 8 hours whereas, isolate A3 controlled after 24 hours. The evaluated insecticides provided a significant reduction in the infestation level, for variable periods.

Characterization, identification and virulence of Metarhizium species from Cuba to control the sweet potato weevil, Cylas formicarius Fabricius (Coleoptera: Brentidae).

Entomopathogenic Metarhizium fungi are widely recognized for their biological control potential. In Cuba, several fungus-based bio-insecticides have been developed and are produced as part of integrated pest management (IPM) programmes for economically relevant agricultural pests. Screening of fungal isolates from the INISAV strain collection was used for the development of bio-insecticides against important pest insects as, for example the sweet potato weevil, Cylas formicarius. Six fungal isolates from Cuba were microscopically, morphologically and molecular-taxonomically characterized using marker sequences ef1a, rpb1 and rpb2, and the 5TEF region of the ef1a gene. Five isolates were assigned to the species Metarhizium anisopliae sensu stricto and one isolate to Metarhizium robertsii. The pathogenic potential was evaluated against adults of C. formicarius, and growth and conidial production on different nutritional media were determined. Metarhizium anisopliae strain LBM-267 displayed pronounced virulence against the sweet potato weevil and abundant conidia production on several culture media. Entomopathogenic fungal isolates from Cuba were assigned to the taxonomic species M. anisopliae sensu stricto and M. robertsii. Virulence assessment with respect to C. formicarius led to the identification of two M. anisopliae isolates holding biocontrol potential. Isolate LBM-11 has previously been developed into the bio-insecticide METASAVE-11 that is widely used to control several species of plant pathogenic weevils, Lepidoptera and thrips in Cuba. Isolate LBM-267 has not been employed previously but is as virulent against C. formicarius as LBM-11; its growth and conidial production capacities on different nutritional media will likely facilitate economically feasible bio-insecticide development. Metarhizium anisopliae isolate LBM-267 has been selected as a promising candidate for biocontrol of the sweet potato weevil, an economically important agricultural pest in Cuba, and for further R&D activities within the framework of the Biological Control Program of Cuba.

Fermentation as an Alternative Process for the Development of Bioinsecticides

Currently, insect pest control is carried out through the application of synthetic insecticides which have been related to harmful effects on both human and environmental health, as well as to the development of resistant pest populations. In this context, the development of new and natural insecticides is necessary. Agricultural and forestry waste or by-products are very low-cost substrates that can be converted by microorganisms into useful value-added bioactive products through fermentation processes. In this review we discuss recent discoveries of compounds obtained from fermented substrates along with their insecticidal, antifeedant, and repellent activities. Fermentation products obtained from agricultural and forestry waste are described in detail. The fermentation of the pure secondary metabolite such as terpenes and phenols is also included.

Commercial development of plant essential oils and their constituents as active ingredients in bioinsecticides

Insecticidal action of plant essential oils has been an area of intensive research in the new millennium, according to a recent bibliometric analysis. Despite this overwhelming research effort, commercialization of bioinsecticides based on essential oils has lagged far behind, although such products have now been used in the USA for over a decade, and in the EU in the last 4–5 years. Recent progress in commercialization of these products is reviewed here. Essential oils and their mono- and sesquiterpenoid constituents are fast-acting neurotoxins in insects, possibly interacting with multiple receptor types. These compounds also display potentially important sublethal behavioural effects in pest insects, including feeding and oviposition deterrence and repellence. Synergy among essential oil terpenoids appears to be a common phenomenon, and a mechanism for this action in rosemary oil has recently been demonstrated. Commercial development of bioinsecticides based on plant essential oils can follow several different pathways producing products with active ingredients differing in their genesis. These include products whose active ingredients consist of (1) a mixture of essential oils; (2) a single essential oil, or a single terpenoid constituent; (3) a blend of terpenoids, synthetically produced, that emulate those in a plant essential oil; and (4) a novel (non-natural) blend of terpenoids obtained from different plant sources. Examples of each of these are provided.

Pathogenicity of an Indigenous Strain of the Entomopathogenic Fungus Metarhizium anisopliae (Hypocreales: Clavicipitaceae) (MET-GRA4 Strain) as a Potential Biological Control Agent Against the Red Palm Weevil (Coleoptera: Dryophthoridae).

Metarhizium anisopliae Metchnikoff (Hypocreales: Clavicipitaceae) is a fungal pathogen that causes disease in various insect pests, and it can be exploited and developed as a biological control agent to combat the red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae). The study on indigenous isolates is crucial especially for development of bioinsecticides in the future. The M. anisopliae strain called MET-GRA4 was tested for pathogenicity against adult red palm weevil and treated in vitro with different spore viabilities. The isolates exhibited pathogenicity with 100% mortality 21 d postinfection. The median lethal time (LT50) for 85% viable spores was 8.6 d, while 39% viable spores had an LT50 value of 21.37 d, with 92 and 16.6% mycosis, respectively. The species MET-GRA4 strain was molecularly characterized using ITS1 and ITS4 from pure culture (Isolate A), mass-produced spores (Isolate B), and infected red palm weevil cadavers (Isolate C). The DNA sequences obtained matched M. anisopliae sequences, with 99% similarity. This new isolate of M. anisopliae has potential as a targeted bioinsecticide for management of red palm weevil.

In Vitro Infectious Risk Assessment of Heliothis virescens ascovirus 3j (HvAV-3j) toward Non-target Vertebrate Cells.

As specific pathogens of noctuid pests, including Spodoptera exigua, S. litura, Helicoverpa armigera, and Mythimna separata, ascoviruses are suitable for the development of bioinsecticides. In this study, the infectivity of Heliothis virescens ascovirus 3j (HvAV-3j) on insect and mammalian cells was evaluated. HvAV-3j infection induced drastic morphological changes in Sf9, HzAM1, SeFB, and HaFB cells, including swelling and detachment. Notably, the latter phenomena did not occur in HvAV-3j-inoculated mammalian cells (HEK293, 7402, HePG2, PK15, ST, and TM3). MTT assays indicated that HvAV-3j inhibited the growth of host insect cells from the 6th hpi, but no effects were detected in the HvAV-3j-inoculated mammalian cells. Furthermore, viral DNA replication, gene transcription, and protein expression were investigated, and the results consistently suggested that HvAV-3j viruses were not able to replicate their genomic DNA, transcribe, or express their proteins in the non-target vertebrate cells. The HvAV-3j genes were only transcribed and expressed in the four insect cell lines. These results indicated that HvAV-3j was infectious to cells derived from S. frugiperda, S. exigua, H. armigera, and H. zea but not to cells derived from human, pig, and mouse, suggesting that ascoviruses are safe to non-target vertebrate cells.

Strategy for high throughput development of bioinsecticides from Chinese tubular cone snail

Strategy for high throughput development of bioinsecticides from Chinese tubular cone snail