Study on the virulence of Metarhizium anisopliae against Spodoptera frugiperda (J. E. Smith, 1797).

This study examined the impact of Metarhizium anisopliae (Hypocreales: Clavicipitaceae) conidia on the eggs, larvae, pupae, and adults of Spodoptera frugiperda. The results showed that eggs, larvae, pupae, and adults exhibited mortality rates that were dependent on the dose. An increased amount of conidia (1.5 × 109 conidia/mL) was found to be toxic to larvae, pupae, and adults after 9 days of treatment, resulting in a 100% mortality rate in eggs, 98% in larvae, 76% in pupae, and 85% in adults. A study using earthworms as bioindicators found that after 3 days of exposure, M. anisopliae conidia did not cause any harmful effects on the earthworms. In contrast, the chemical treatment (positive control) resulted in 100% mortality at a concentration of 40 ppm. Histopathological studies showed that earthworm gut tissues treated with fungal conidia did not show significant differences compared with those of the negative control. The gut tissues of earthworms treated with monocrotophos exhibited significant damage, and notable differences were observed in the chemical treatment. The treatments with 70 and 100 µg/mL solutions of Eudrilus eugeniae epidermal mucus showed no fungal growth. An analysis of the enzymes at a biochemical level revealed a decrease in the levels of acetylcholinesterase, α-carboxylesterase, and ß-carboxylesterase in S. frugiperda larvae after exposure to fungal conidia. This study found that M. anisopliae is effective against S. frugiperda, highlighting the potential of this entomopathogenic fungus in controlling this agricultural insect pest.

Biodegradation of pesticide in agricultural soil employing entomopathogenic fungi: Current state of the art and future perspectives.

Pesticides play a pivotal role in agriculture for the effective production of various crops. The indiscriminate use of pesticides results in the significant bioaccumulation of pesticide residues in vegetables. This situation is beyond the control of consumers and poses a serious health issue for human beings. Occupational exposure to pesticides may occur for farmers, agricultural workers, and industrial producers of pesticides. This occupational exposure primarily causes food and water contamination that gets into humans and environmental pollution. Depending on the toxicity of pesticides, the causes and effects differ in the environment and in human health. The number of criteria used and the method of implementation employed to assess the effect of pesticides on humans and the environment have been increasing, as they may provide characterization of pesticides that are already on the market as well as those that are on the way. The biological control of pests has been increasing nowadays to combat all these effects caused by synthetic pesticides. Myco-biocontrol has received great attention in research because it has no negative impact on humans, the environment, or non-target species. Entomopathogenic fungi are microbes that have the ability to kill insect pests. Fungi also make enzymes like the lytic enzymes, esterase, oxidoreductase, and cytochrome P450, which react with chemical residues in the field and break them down into nontoxic substances. In this review, the authors looked at how entomopathogenic fungi break down insecticides in the environment and how their enzymes break down insecticides on farms.

Biocontrol effect of entomopathogenic fungi Metarhizium anisopliae ethyl acetate-derived chemical molecules: An eco-friendly anti-malarial drug and insecticide.

Insect pests represent a major threat to human health and agricultural production. With a current over-dependence on chemical insecticides in the control of insect pests, leading to increased chemical resistance in target organisms, as well as side effects on nontarget organisms, the wider environment, and human health, finding alternative solutions is paramount. The employment of entomopathogenic fungi is one such potential avenue in the pursuit of greener, more target-specific methods of insect pest control. To this end, the present study tested the chemical constituents of Metarhizium anisopliae fungi against the unicellular protozoan malaria parasite Plasmodium falciparum, the insect pests Anopheles stephensi Listen, Spodoptera litura Fabricius, and Tenebrio molitor Linnaeus, as well as the nontarget bioindicator species, Eudrilus eugeniae Kinberg. Fungal crude chemical molecules caused a noticeable anti-plasmodial effect against P. falciparum, with IC50 and IC90 values of 11.53 and 7.65 µg/mL, respectively. The crude chemical molecules caused significant larvicidal activity against insect pests, with LC50 and LC90 values of 49.228-71.846 µg/mL in A. stephensi, 32.542-76.510 µg/mL in S. litura, and 38.503-88.826 µg/mL in T. molitor at 24 h posttreatment. Based on the results of the nontarget bioassay, it was revealed that the fungal-derived crude extract exhibited no histopathological sublethal effects on the earthworm E. eugeniae. LC-MS analysis of M. anisopliae-derived crude metabolites revealed the presence of 10 chemical constituents. Of these chemicals, three major chemical constituents, namely, camphor (15.91%), caprolactam (13.27%), and monobutyl phthalate (19.65%), were highlighted for potential insecticidal and anti-malarial activity. The entomopathogenic fungal-derived crude extracts thus represent promising tools in the control of insect pests and malarial parasites.

Desiccation tolerance of Termitidae termites in relation to their nest type.

The family Termitidae is renowned for its diverse nesting behaviors, with the evolution of epigeal and arboreal nests hypothesized to increase desiccation stress due to greater exposure to air. However, these nests may also alleviate desiccation stress through humidity regulation. To explore the implications of acquiring epigeal and arboreal nests, we investigated desiccation tolerance traits in 16 Termitidae termite species with varying nest types and analyzed trait correlations. Principal component analysis revealed that termites constructing epigeal and arboreal nests exhibited reduced water loss rates and enhanced survival under desiccated conditions. Furthermore, termites building arboreal nests displayed a notably higher water content. Redundancy analysis demonstrated that nest types accounted for a substantial portion (57.2%) of the observed variation in desiccation tolerance. These findings support the hypothesis that epigeal and arboreal nests in termites are associated with increased desiccation stress and increased desiccation tolerance. These findings highlight the role of nest type in influencing desiccation tolerance mechanisms and water regulation strategies in termites.

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.

Essential oils from Acacia nilotica (Fabales: Fabaceae) seeds: May have insecticidal effects?

In the present study Acacia nilotica seed derived essential oils were tested against Spodoptera litura, Tenebrio molitor, Oxycarenus hyalinipennis, and Aphis fabae, as well as their effects on non-target species Eudrilus eugeniae and Artemia salina at 24 h post treatment. The seed essential oil produced insecticidal activity against A. fabae (LC50 = 41.679, LC90 = 75.212 µl/mL), O. hyalinipennis (LC50 = 37.629, LC90 = 118.485 µl/mL), T. molitor (LC50 = 56.796, LC90 = 201.912 µl/mL), and S. litura (LC50 = 62.215, LC90 = 241.183 µl/mL). Essential oils do not cause a remarkable effect on E. eugeniae and A. salina cytotoxicity. The essential oils produced a lower effect on Artemia salina (LC50 = 384.382, LC90 = 1341.397 µl/mL) and no lethal effects were observed on E. eugeniae. The histopathological evaluation showed no sub-lethal effects of essential oils on earthworm gut tissues. GC-MS analysis results revealed that the major chemical constituent was hexadecane (19.560%) and heptacosane (17.214%) and FT-IR analysis revealed the presence of alkanes and alkyles, aromatics, and amides functional groups that may be involved in insecticidal activity. Overall, the results showed that the seed derived essential oil has excellent insecticidal action against major agricultural insect pests and may therefore offer an environmentally benign alternative to conventional insecticide.

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.

Bio-efficacy of insecticidal molecule emodin against dengue, filariasis, and malaria vectors.

Emodin, a compound isolated from Aspergillus terreus, was studied using chromatographic and spectroscopic methods and compound purity (96%) was assessed by TLC. Furthermore, high larvicidal activity against Aedes aegypti-AeA (LC50 6.156 and LC90 12.450 mg/L), Culex quinquefasciatus-CuQ (8.216 and 14.816 mg/L), and Anopheles stephensi-AnS larvae (6.895 and 15.24 mg/L) was recorded. The first isolated fraction (emodin) showed higher pupicidal activity against AeA (15.449 and 20.752 mg/L). Most emodin-treated larvae (ETL) showed variations in acetylcholine esterase, α and ß-carboxylesterases, and phosphatase activities in the 4th instar, indicating the intrinsic differences in their biochemical changes. ETL had numerous altered tissues, including muscle, gastric caeca, hindgut, midgut, nerve ganglia, and midgut epithelium. Acute toxicity of emodin on brine shrimp Artemia nauplii (54.0 and 84.5 mg/L) and the zebrafish Danio rerio (less toxicity observed) was recorded. In docking studies, Emodin interacted well with odorant-binding-proteins of AeA, AnS, and CuQ with docking scores of - 8.89, - 6.53, and - 8.09 kcal mol-1, respectively. Therefore, A. terreus is likely to be effective against mosquito larvicides.

Effects of phytocompound Precocene 1 on the expression and functionality of the P450 gene in λ-cyhalothrin-resistant Spodoptera litura (Fab.).

Spodoptera litura (Fabricius) is an agriculturally significant polyphagous insect pest that has evolved a high level of resistance to conventional insecticides. A dietary assay was used in this work to assess the resilience of field populations of S. litura to λ-cyhalothrin. Analysis of the function and expression of the cytochrome P450 gene was used to test the sensitivity of S. litura larvae to sub-lethal concentrations of the insecticidal plant chemical Precocene 1, both by itself and in combination with λ-cyhalothrin. The activity of esterase enzymes (α and ß) was found to decrease 48 h post treatment with Precocene 1. The activity of GST enzyme and cytochrome P450 increased with Precocene 1 treatment post 48 h, however. Expression studies revealed the modulation by Precocene 1 of cytochrome P450 genes, CYP4M16, CYP4M15, CYP4S8V4, CYP4G31, and CYP4L10. While CYP4M16 expression was stimulated the most by the synergistic Precocene 1 + λ-cyhalothrin treatment, expression of CYP4G31 was the most down-regulated by Precocene 1 exposure. Hence, it is evident that λ-cyhalothrin-resistant pest populations are still sensitive to Precocene 1 at a sublethal concentration that is nevertheless capable of hindering their development. Precocene 1 can therefore be considered a potent candidate for the effective management of insecticide-resilient S. litura.

Phytosynthesis of Silver Nanoparticle (AgNPs) Using Aqueous Leaf Extract of Knoxia sumatrensis (Retz.) DC. and Their Multi-Potent Biological Activity: An Eco-Friendly Approach.

Green synthesis of silver nanoparticles (AgNPs) has gained greater interest among chemists and researchers in this current scenario. The present research investigates the larvicidal and anti-proliferation activity of AgNPs derived from Knoxia sumatrensis aqueous leaf extract (K. sumatrensis-ALE) as a potential capping and reducing candidate. The synthesized AgNPs were characterized through-UV-spectra absorption peak at 425 nm. The XRD and FT-IR studied displayed the crystalline nature and presence of functional groups in prepared samples. FE-SEM showed the hexagonal shape of NPs with the size of 7.73 to 32.84 nm. The synthesized AgNPs displayed superior antioxidant and anti-proliferative activity (IC50 53.29 µg/mL) of breast cancer cell line (MCF-7). Additionally, larvicidal activity against mosquito vector Culex quinquefasciatus larvae delivered (LC50-0.40, mg/L, and LC90-15.83) significant mortality rate post treatment with synthesized AgNPs. Overall, the present research illustrates that the synthesized AgNPs have high biological potential and present a perfect contender in the pharmacological and mosquitocidal arena.

Larvicidal and Antifeedant Effects of Copper Nano-Pesticides against Spodoptera frugiperda (J.E. Smith) and Its Immunological Response.

This study aimed to synthesize and evaluate the efficacy of CuO NPs (copper oxide nanoparticles) with varying test concentrations (10−500 ppm) against larvicidal, antifeedant, immunological, and enzymatic activities against larvae of S. frugiperda at 24 h of treatment. Copper nanoparticles were characterized by using a scanning electron microscope (SEM) and energy dispersive X-ray (EDaX) analysis. The EDaX analysis results clearly show that the synthesized copper nanoparticles contain copper as the main element, and the SEM analysis results show nanoparticle sizes ranging from 29 to 45 nm. The CuO NPs showed remarkable larvicidal activity (97%, 94%, and 81% were observed on the 3rd, 4th, and 5th instar larvae, respectively). The CuO NPs produced high antifeedant activity (98.25%, 98.01%, and 98.42%), which was observed on the 3rd, 4th, and 5th instar larvae, respectively. CuO NPs treatment significantly reduced larval hemocyte levels 24 h after treatment; hemocyte counts and sizes changed in the CuO NPs treatment compared to the control. After 24 h of treatment with CuO NPs, the larval acetylcholinesterase enzyme levels decreased with dose-dependent activity. The present findings conclude that CuO NPs cause remarkable larvicidal antifeedant activity and that CuO NPs are effective, pollution-free green nano-insecticides against S. frugiperda.

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.

The inhibitory action of plant extracts on the mycelial growth of Ascosphaera apis, the causative agent of chalkbrood disease in Honey bee.

Ascosphaera apis is a fungal pathogen, which causes chalkbrood disease in bees and is threatening beekeeping worldwide. The demand for organic honey for export has lately heightened hence the biological control is the option. This study aimed at the in vitro evaluation of the potency of plant extracts against chalkbrood disease for the possibility of being employed as a biological control strategy. The results showed that the combination of plant extracts from cinnamon with spearmint, cinnamon with lemongrass, cinnamon with geranium, and cinnamon with palmarosa at a concentration of 25% and 12.5% inhibited mycelial growth of A. apis by 100%. This demonstrated the potentiality of combining different plant extracts in controlling this disease. In addition, oregano caused inhibition of up to 100% singly. Conclusively, cinnamon in combination with several extracts has a great potential in curbing this disease while oregano offers an amazing remedy and hence the best formulations should be generated for the beekeeper to utilize.

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.

Evaluation of the Potential of a Lectin Extracted from Polygonumpersicaria L. as a Biorational Agent against Sitophilusoryzae L.

Rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), is one of the most destructive stored-product pests that is resistant to a wide range of chemical insecticides. In the present study, we investigated whether a lectin extracted from Polygonum persicaria L. (PPA) can be used as a biorational agent to control such insect pests. Along with the lethal digestive assay, the sub-lethal insecticidal activities of PPA, including the effects on digestive, detoxifying, and antioxidant enzyme activities, were evaluated against S. oryzae adults. The effect of feeding a diet containing PPA and carob extract as a food attractant on the mortality of S. oryzae adults was also investigated. Feeding on the diet containing PPA resulted in a significant mortality of S. oryzae adults with a LC50 (Lethal Concentration to kill 50% of insects) of 3.68% (w/w). The activity of digestive enzymes, including α-amylase, α-glucosidase, TAG-lipase, trypsin, chymotrypsin, elastase, and carboxy- and aminopeptidase, were decreased by the sub-lethal concentration of PPA. Detoxifying and antioxidant enzymes, including esterase, superoxide dismutase, catalase, glutathione-S-transferase, ascorbate peroxidase, glucose 6-phosphate dehydrogenase, and malondialdehyde, were activated in adults affected by PPA. These findings indicated that PPA, in addition to causing digestive disorders, leads to oxidative stress in S. oryzae. The presence of carob extract had no effect on the PPA-induced mortality of the insect. According to the results of the present study, PPA has promising insecticidal efficiency against S. oryzae. In addition, the usage of PPA with a food attractant carob extract in bait traps can be recommended as a new biorational formulation in S. oryzae management.

Association of IFNA16 and TNFRSF19 Polymorphisms with Intramuscular Fat Content and Fatty Acid Composition in Pigs.

Interferon-alpha-16 (IFNA16) and tumor necrosis factor receptor superfamily member 19 (TNFRSF19) are cytokines that may play a role in adipogenesis and fatness. Single nucleotide polymorphisms (SNPs) of the porcine IFNA16 and TNFRSF19 genes were verified and their association with intramuscular fat (IMF) content and fatty acid (FA) composition were evaluated in commercial crossbred pigs. Two non-synonymous SNPs of the porcine IFNA16 c.413G > A and TNFRSF19 c.860G > C loci were detected in commercial crossbred pigs. The porcine IFNA16 c.413G >A polymorphism was significantly associated with stearic acid, total saturated FAs (SFAs), and the ratio of monounsaturated FAs (MUFAs) to SFAs (p < 0.05). Furthermore, the porcine TNFRSF19 c.860G > C polymorphism was found to be significantly associated with IMF content and arachidic acid levels (p < 0.05). The results revealed that porcine IFNA16 and TNFRSF19 polymorphisms are related to IMF content and/or FA composition and affirmed the importance of these cytokine genes as potential candidate genes for lipid deposition and FA composition in the muscle tissue of pigs.

Evaluation of Native Entomopathogenic Fungi for the Control of Fall Armyworm (Spodoptera frugiperda) in Thailand: A Sustainable Way for Eco-Friendly Agriculture.

Fall armyworm, Spodoptera frugiperda, entered Thailand in late 2018 and has now spread in several regions, with devastating effects in maize and rice production, which are some of the most important cereals in the world. Since then, farmers have utilized the available chemical insecticides to try to control it, but their efforts have been futile. Instead, they have ended up using extraordinary dosages, hence threatening non-target species and other fauna and flora, as well as being costly. In this regard, research has been ongoing, aiming to come up with eco-friendly solutions for this insect. We surveyed and collected various isolates of native entomopathogenic fungi intending to test their efficacy against fall armyworm. Six isolates of entomopathogenic fungi were obtained and identified to Beauveria bassiana based on morphological characteristics and multi-gene phylogenetic analyses. Thereafter, the six isolates of B. bassiana were used to perform efficacy experiments against fall armyworm. Additionally, the glycosyl transferase-like protein 1 (GAS1) gene was analyzed. Consequently, all the isolates showed efficacy against S. frugiperda, with isolate BCMU6 causing up to 91.67% mortality. Further, molecular analysis revealed that all the isolates possess the GAS1 gene, which contributed to their virulence against the insect. This is the first report of utilizing native entomopathogenic B. bassiana to manage S. frugiperda in Thailand, with the revelation of GAS1 as a factor in inducing virulence and cuticle penetration. This study has provided valuable information on the potential development of Beauveria bassiana as an eco-friendly bioinsecticide for the management of fall armyworm in Thailand.

RNA Interference Suppression of v-ATPase B and Juvenile Hormone Binding Protein Genes Through Topically Applied dsRNA on Tomato Leaves: Developing Biopesticides to Control the South American Pinworm, Tuta absoluta (Lepidoptera: Gelechiidae).

The South American pinworm Tuta absoluta (Meyrick) (Family: Gelechiidae) is one of the most devastating lepidopteran pests in the developing countries of South America, Africa, and Asia. This pest is classified as the most serious threat for tomato production worldwide. In the present study, we analyzed RNAi-mediated control through exogenously applied dsRNA delivery on tomato. The dsRNA treatments were made to target the juvenile hormone binding protein and the v-ATPase B. Both mRNA targets were cloned, validated by sequencing, and used to produce each dsRNA. After treatments the relative transcript expression was analyzed using qRTPCR to assess to efficacy of RNAi. A leaf-dip assay was used to provide late 2nd instar larvae three feeding access periods: 24, 48, and 72 h, to evaluate the effect of gene silencing of each target. Larvae were fed tomato leaves coated with five different RNAi concentrations (10, 20, 30, 40, and 50 micrograms/centimeter-squared), that suppressed two genes (juvenile hormone protein, JHBP, and vacuolar-type adenosine triphosphatase enzyme, v-ATPase). Treatments with dsRNA showed a significant increase in mortality at 24, 48, and 72 h after ingestion (P < 0.01, α = 0.05), along with reduced leaf damage, and increased feeding deterrence. The results suggest that these two RNAi products may provide a suitable treatment for control of this and other lepidopteran pests.

Insecticidal Effect of Zinc Oxide Nanoparticles against Spodoptera frugiperda under Laboratory Conditions.

Fall armyworm Spodoptera frugiperda is a major pest of corn, rice, and sorghum among other crops usually controlled using synthetic or biological insecticides. Currently, the new invention of nanotechnology is taking root in the agricultural industry as an alternative source of pest management that is target-specific, safe, and efficient. This study sought to determine the efficacy of commercial Zinc Oxide (ZnO) nanoparticles (NPs) towards S. frugiperda under laboratory conditions. ZnO NPs were diluted into different concentrations (100-500 ppm), where the baby corn used to feed the S. frugiperda larvae was dipped. The development of the insect feeding on food dipped in ZnO solution was significantly (p < 0.05) affected, and the number of days that the insect took to complete its life cycle had a significant difference compared to the control. There was a significant difference in the adults' emergence in all the concentrations of ZnO NPs compared to the control, with over 90% of the eggs successfully going through the life cycle until adult emergence. Additionally, several body malformations were observed throughout the lifecycle of the insect. Also, the fecundity of the females was greatly affected. The findings of this study suggest the possibility of exploitation of ZnO nanoparticles not only to manage S. frugiperda but to significantly reduce their population in the ecosystem through body deformations, reduced fecundity, reduced oviposition, and hatchability of eggs. It will be a valuable tool in integrated pest management regimens.

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

Currently, medical and stored grain pests are major concerns of public health and economies worldwide. The synthetic pesticides cause several side effects to human and non-target organisms. Copper nanoparticles (CuNPs) were synthesized from an aqueous extract of Metarhizium robertsii and screened for insecticidal activity against Anopheles stephensi, Aedes aegypti, Culex quinquefasciatus, Tenebrio molitor and other non-target organisms such as Artemia salina, Artemia nauplii, Eudrilus eugeniae and Eudrilus andrei. The synthesized copper nano-particles were characterized using, UV-vis spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Energy Dispersive X-Ray analysis (EDaX), High Resolution Scanning Electron Microscope (HR-SEM) and Atomic Force Microscope (AFM) analysis. Insects were exposed to 25 µg/mL concentration produced significant mortality against larvae of A. stephensi, A. aegypti, C. quinquefasciatus and T. molitor. The lower toxicity was observed on non-target organisms. Results showed that, M. robertsii mediated synthesized CuNPs is highly toxic to targeted pests while they had lower toxicity were observed on non-target organisms.