Frugiperda Larvae Research Articles

PluriBAC: A Versatile Baculovirus-Based Modular System to Express Heterologous Genes in Different Biotechnological Platforms.

Baculoviruses are insect-specific pathogens widely used in biotechnology. In particular, the Autographa californica nucleopolyhedrovirus (AcMNPV) has been exploited as a platform for bio-inputs production. This is why the improvement of the technologies used for the production of recombinant baculoviruses takes on particular relevance. To achieve this goal, we developed a highly versatile baculoviral transfer vector generation system called PluriBAC. The PluriBAC system consists of three insert entry levels using Golden Gate assembly technology. The wide availability of vectors and sticky ends allows enough versatility to combine more than four different promoters, genes of interest, and terminator sequences. Here, we report not only the rational design of the PluriBAC system but also its use for the generation of baculoviral reporter vectors applied to different fields of biotechnology. We demonstrated that recombinant AcMNPV baculoviruses generated with the PluriBAC system were capable of infecting Spodoptera frugiperda larvae. On the other hand, we found that the recombinant budded virions (BV) generated using our system were capable of transducing different types of tumor and normal cells both in vitro and in vivo. Our findings suggest that the PluriBAC system could constitute a versatile tool for the generation of insecticide and gene therapy vectors.

Toxicity of Calophyllum soulattri, Piper aduncum, Sesamum indicum and their potential mixture for control Spodoptera frugiperda

Abstract Spodoptera frugiperda caused severe damage to the maize plant. Botanical insecticides are a choice to control this pest. This study aims to determine the ethanol extract of Calophyllum soulattri stem bark, methanol extract of Piper aduncum fruit, and Sesamum indicum oil, and their potential mixture for controlling S. frugiperda. The bioassays were carried out in laboratory conditions using second instar S. frugiperda larvae from mass rearing in the laboratory. A toxicity test was performed using the leaf-residual feeding method. The result showed that the mortality of S. frugiperda for C. soulattri is LC50 = 0.349% and LC95 = 3.256% and that for P. aduncum is LC50 = 0.530% and LC95 = 4.666%. S. indicum oil (at 10% concentration) only caused the mortality of S. frugiperda by 27.5%. Insecticide mixture can increase the toxicity of the insecticide. The observation mortality of S. frugiperda for C. soulattri and P. aduncum (1:2) extracts mixture were LC50 = 0.233% and LC95 = 0.808%. At the same time, C. soulattri extract dan S. indicum oil mixture (4:1) were LC50 = 0.268% and LC95 = 0.931%. The treatments with a single insecticide and their mixtures affected the biological activity of S. frugiperda by reducing the area of feed consumption, and the longer the larval development time, the lower the pupal weight of S. frugiperda. Our findings indicated that a mixture of C. soulattri and P. aduncum extract, then C. soulattri extract, and S. indicum oil could potentially develop as effective insecticide for controlling S. frugiperda.

Dose Effects of Flubendiamide and Thiodicarb against Spodoptera Species Developing on Bt and Non-Bt Soybean.

An increase in Spodoptera species was reported in Bt soybean fields expressing Cry1Ac insecticidal proteins in Brazil, requiring additional management with chemical insecticides. Here, we evaluated the dose effects of flubendiamide and thiodicarb on Spodoptera cosmioides (Walker, 1858), Spodoptera eridania (Stoll, 1782), Spodoptera albula (Walker, 1857) and Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) that survived on MON 87751 × MON 87708 × MON 87701 × MON 89788, expressing Cry1A.105, Cry2Ab2 and Cry1Ac; MON 87701 × MON 89788 soybean, expressing Cry1Ac; and non-Bt soybean. On unsprayed Cry1A.105/Cry2Ab2/Cry1Ac soybean, only S. frugiperda showed ~60% mortality after 10 d, whereas S. cosmioides, S. eridania and S. albula showed >81% mortality. The surviving larvae of all species on this Bt soybean showed >80% mortality when exposed to the field label dose of flubendiamide (70 mL/ha) or thiodicarb (400 g/ha) or at 50% of these doses. In contrast, all four species had <25% and <19% mortality on Cry1Ac and non-Bt soybean, respectively. The surviving S. cosmioides, S. eridania and S. albula on these soybean types presented >83% mortality after exposure to both dose levels of flubendiamide and thiodicarb. Some S. frugiperda larvae surviving on Cry1Ac and non-Bt soybean sprayed with a 50% dose of either insecticide developed into adults. However, the L1 larvae developing on Cry1Ac soybean leaves sprayed with flubendiamide and the L2 larvae on this soybean sprayed with thiodicarb had a prolonged immature stage, and the females displayed lower fecundity, which are likely to impact S. frugiperda population growth on soybean.

Bioassay test of Beauveria bassiana alginate pellet formulation on mortality of Spodoptera frugiperda in the laboratory

The attack level of Spodoptera frugiperda greatly influences the production of maize in the field. The use of insecticides for control certainly has many negative impacts so that they switch to more environmentally friendly controls. One of them uses the entomopathogenic fungus (EPF) Beuvaria bassiana which has the ability to aggressively paralyze insect larvae and imago that are affected by its spores. The B. bassiana can be mass produced in both solid and liquid media. The aim of this study was to test the effectiveness of the B. bassiana alginatepellet formulation on spore density and mortality of Spodoptera frugiperda test larvae in the laboratory. The efficacy test of the formulation on the test insects was carried out by dipping the test larvae feed into the B. bassiana alginate pellet suspension in each treatment using 50third instar of larvae. Corn had an effect on the spore density of B. bassiana alginate pellets, the highest spore density with conidia density of 2.35x108 conidia/mlwas found in the wheat flour treatment as well as with the highest percentage of mortality of Spodoptera frugiperda larvae, namely on day 6-9 DAA (days after application) in a row of 60%, 68% and 70%. In addition, it can be concluded that the alginate pellet formulation made from the active entomopathogenic fungus Beauveria bassiana is effective in controlling the population of Spoduptura frugiperda larvae.

Exploration of Spodoptera frugiperda natural enemies on Zea mays cultivation area

The insect pest Fall Armyworm Spodoptera frugiperda is a new invasive pest in Indonesia and potential as a major pest on maize. Maize field at two area (highlands and lowlands) were studied for natural enemies exploration of S. frugiperda in North Sumatra, namely Deli Serdang District, Langkat, Karo and Dairi. Two maize planting areas attack by S. frugiperda from each district were selected. Plants sample that showed symptoms of S. frugiperda attack were taken by taking S. frugiperda larvae (live or dead), egg groups and insect predator. All insect presence in the area was collected. The egg and larva of S. frugiperda were kept in a laboratory until the parasitoid and pathogen emergence. The result showed that the predator found were Coccinelidae, Dermaptera (Euboriellia sp) at all surveyed area, but Sycanus sp (Reduviidae) found at Langkat District and Rhynocoris sp. found at Karo and Dairi. Tachinidae parasitoid was found at Dairi District. Spodotera fugiperda larva infected by fungi was found at Deli Serdang and Langkat district.

Induced expression modes of genes related to Toll, Imd, and JAK/STAT signaling pathway-mediated immune response in Spodoptera frugiperda infected with Beauveria bassiana.

Spodoptera frugiperda is one of the most harmful pests that attack maize and other major food crops and causes huge economic loss every year in China and other countries and regions. Beauveria bassiana, a kind of entomological fungus that is highly pathogenic to pests, is harmless to the environment and human beings. However, at present, S. frugiperda has gradually developed resistance to many pesticides and microbial insecticides. In this study, transcriptome sequencing was conducted to analyze the differences in gene expression between B. bassiana-infected and -uninfected S. frugiperda. More than 160Gb of clean data were obtained as 150-bp paired-end reads using the Illumina HiSeq™ 4000 platform, and 2,767 and 2,892 DEGs were identified in LH36vsCK36 and LH144vsCK144, respectively. In order to explore the roles of JAK/STAT, Toll, and Imd signaling pathways in antifungal immune response in S. frugiperda against B. bassiana infection, the expression patterns of those signaling pathway-related genes in B. bassiana-infected S. frugiperda were analyzed by quantitative real-time PCR. In addition, antifungal activity experiments revealed that the suppression of JAK/STAT, Toll, and Imd signaling pathways by inhibitors could inhibit the antifungal activity to a large extent and lead to increased sensitivity of S. frugiperda to B. bassiana infection, indicating that JAK/STAT, Toll, and Imd signaling pathways and their associated genes might be involved in the synthesis and secretion of antifungal substances. This study implied that JAK/STAT, Toll, and Imd signaling pathways played crucial roles in the antifungal immune response of the S. frugiperda larvae, in which the related genes of these signaling pathways could play special regulatory roles in signal transduction. This study would improve our understanding of the molecular mechanisms underlying innate immunity and provide the basis for a wide spectrum of strategies against antifungal resistance of S. frugiperda.

Reaction of Maize Genotypes against Fall Armyworm, Spodoptera frugiperda (Smith) in Madhya Pradesh, India

Aims: To identify the less susceptible varieties, allowing for targeted pest management strategies, reduced pesticide use, increased resilience to pest outbreaks, and long-term sustainable pest control solutions.&#x0D; Study Design: Randomized Block Design.&#x0D; Place and Duration of Study: Research Farm, College of Agriculture, Gwalior (Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya, Gwalior) during two consecutive years i.e., Kharif, 2021-22 and Kharif 2022-23.&#x0D; Methodology: In the experiment, twelve different varieties were sown on 17th July 2021 and 17th July 2022 during both the consecutive years respectively. Observations on the number of fall armyworm, Spodoptera frugiperda larvae and plant damage per cent were recorded from randomly selected ten plants at weekly intervals. Observations for FAW was also be recorded with visual scoring method. A numerical scale (0-9), also known as the Davis scale, was used to evaluate leaf damage.&#x0D; Results: The result of both the year indicated that not all varieties were found to be completely resistant to fall armyworm. For the purpose of interpreting the results, all the varieties were categorized for their reaction based on average data of both the years (Kharif 2021 and Kharif 2022) of mean larval population, mean plant damage percent, and leaf damage scoring. Based on statistical categorization, it was determined that the varieties NWMH-2002 and JM 218 exhibited lower susceptibility. On the other hand, the varieties Dkc-9141, Maize 3845, PAC 740, Yashoda gold, PM 303, Maize Ranker, Maize 5402, and Maize 3046 were classified as moderately susceptible. Lastly, Sona 5101 and M-909 were identified as highly susceptible varieties.&#x0D; Conclusions: It concluded that the varieties NWMH-2002 and JM 218 exhibited lower susceptibility against fall armyworm.

Biologi dan neraca kehidupan ulat grayak jagung, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) pada tongkol jagung muda (Zea mays Linn.) sebagai pakan alternatif

Penyediaan ulat Spodoptera frugiperda dalam jumlah banyak sebagai bahan penelitian memerlukan teknologi perbanyakan menggunakan pakan alternatif. Tongkol jagung muda memiliki potensi untuk dikembangkan sebagai pakan alternatif. Penelitian biologi dan neraca kehidupan S. frugiperda dengan pakan tongkol jagung muda sejauh ini belum pernah dilakukan. Penelitian ini bertujuan mendapatkan informasi biologi, morfologi, dan neraca kehidupan S. frugiperda dengan pakan tongkol jagung muda. Larva diperoleh dari pertanaman jagung di Bantarkambing, Bogor. Sebanyak 110 larva hasil F1 dipelihara secara individu dalam wadah berisi tongkol jagung muda sampai menjadi pupa, kemudian pupa dipindahkan ke wadah berisi tanah. Sebanyak 30 pasang imago dipelihara dalam kurungan berisi tanaman jagung. Pengamatan morfologi, biologi, dan neraca kehidupan dilakukan setiap hari, dimulai dari telur sampai imago mati. Hasil menunjukkan adanya variasi warna dan ukuran telur, larva, pupa, dan imago. Rata-rata lama stadia telur, larva, pra-pupa berturut-turut 2,47, 14,96, dan 1,83 hari. Lama stadium pupa 9,75 hari (jantan), dan 8,81 hari (betina). Siklus hidup berlangsung selama 37,69 (jantan), dan 37,7 (betina). Masa pra-oviposisi, oviposisi, dan pasca-oviposisi berlangsung selama 1,60, 7,90, dan 2,26 hari. Lama hidup imago adalah 11,34 hari (jantan) dan 11,76 hari (betina). Jumlah telur yang diletakkan rata-rata adalah 1.365,86/betina butir dengan tingkat penetasan 94,68%. Kurva kesintasan S. frugiperda termasuk tipe I, dengan laju reproduksi kotor (GRR) 1.442,49 individu/generasi dan laju reproduksi bersih (Ro) 1.342,77 individu/induk/generasi. Laju pertambahan intrinsik (r) 0,23 individu/induk/hari, rataan lama generasi (T) 31,23 hari, dan waktu yang dibutuhkan populasi untuk berlipat ganda (DT) 3,01 hari. Tongkol jagung muda dapat dijadikan pakan alternatif dalam perbanyakan S. frugiperda.

Efektivitas Isolat Nematoda Entomopatogen Steinernema sp. Produksi PPAH Kabupaten Kediri terhadap Mortalitas Larva Spodoptera frugiperda J. E. Smith

Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) is a pest that has just entered Indonesia since 2019 and has adapted and become an important pest in corn plants. Therefore, we need a control by utilizing biological control agents that exist in nature, one of which is the entomopathogenic nematode type Steinernema sp. which has been developed by the Biological Agent Service Post (PPAH) "Sidodadi" in the Plosoklaten District, Kediri Regency. The methods used in this study were: collection and rearing of S. frugiperda pests; breeding of entomopathogenic nematodes Steinernema sp. in vivo. The application of an entomopathogenic nematode to test pathogenicity against 3rd instar S. frugiperda larvae. The application treatments used were population densities of 1.000 JI/ml, 800 JI/ml, 400 JI/ml, 200 JI/ml plus a control treatment. The study was designed with a single Completely Randomized Design (CRD) with six treatments and was repeated four times. Each replication consisted of 10 S. frugiperda larvae. Parameters observed included mortality of S. frugiperda larvae due to Steinernema sp.. Effectiveness of Steinernema sp. by calculating the LT50 value. Observation of biological symptoms of S. frugiperda infected with Steinernema sp. and calculation of the infection rate of Steinernema sp.. Data from observations were analyzed using a 5% ANOVA. If there is a significant difference, further DMRT testing is carried out. The effectiveness test was carried out by calculating the LT50 value using Finney's (1971) probit analysis. Based on observations for 120 hours, it was shown that entomopathogenic nematode PPAH isolate was effective in killing S. frugiperda larvae. PPAH isolate entomopathogenic nematode was effective in causing mortality in S. frugiperda larvae. The highest mortality value of S. frugiperda due to entomopathogenic nematode treatment was 97.5% in treatment with 800 JI/ml and 1000 JI/ml at 120 hours after application observation. The fastest LT50 value causing mortality in S. frugiperda larvae was in the 1000 JI/ml of 32.60 hours. The treatment with the longest LT50 value caused the mortality of 50% of the test insects, namely the 200 JI/ml over 95.88 hours. Observation of the infection rate showed the highest infection rate was found in the 1000 JI/ml at 24 hours after application with as many as 0.02% tails, this is because that the higher the inoculated entomopathogenic nematode population, the higher the infection rate value.

Laboratory evaluation of selected botanicals and insecticides against invasive Spodoptera frugiperda (Lepidoptera: Noctuidae)

BackgroundMaize is an economical crop of China, and its production has been severely affected by the invasive Spodoptera frugiperda in recent year. Application of synthetic pesticides are one of the most effective practices against FAW as an emergency control. This pest causes serious damage to the maize crop worldwide in recent decade, especially in China. MethodsTo find an alternative to synthetic insecticides there were total 16 different chemicals were used including ten botanical insecticides comprising of seven botanicals, azadirachtin, pyrethrin, nicotine, osthole, rotenone, Celastrus angulatus, matrine, and three insect growth regulators, diflubenzuron, lufenuron and buprofezin. Six synthetic insecticides, including emamectin benzoate, indoxacarb, imidacloprid and thiamethoxan, chlorantraniliprole, chlorfenapyr, were evaluated against 2nd instar of S. frugiperda larvae using leaf-dip method. ResultsThe results revealed that osthole, azadirachtin, buprofezin and pyrethrin were showed the significant larval mortality of 98.0, 96.7, 94.0 and 90.7%, in 120 h observation and exhibiting minimum LC50 (39.04, 35.58, 61.45 and 48.46 mg/L, respectively) and LT50 (48.91, 68.85, 58.67 and 58.57 h, respectively) values. Among tested synthetic insecticides, emamectin benzoate, chlorantraniliprole and chlorfenapyr were showed significant higher mortality against larvae of S. frugiperda (99.3, 96.0 and 89.3%, respectively) in 72 h observation by exhibiting minimum LC50 (0.26, 0.39 and 0.72 mg/L, respectively) and and LT50 (10.18, 10.57 and 13.42 h, respectively) values. More study is needed to test the laboratory findings in the field, although the efficient biorational pesticides might be utilized as part of integrated pest management against S. frugiperda. ConclusionThe effective chemicals could be used in the management for S. frugiperda. The highest discriminating concentrations of tested botanical insecticides, insect growth regulators and insecticides caused significant mortality of S. frugiperda larvae.

Comparative analysis of Beauveria bassiana submerged conidia with blastospores: yield, growth kinetics, and virulence

In submerged culture, the entomopathogenic fungus Beauveria bassiana yields submerged conidia and single-celled yeast-like form referred to as blastospores. Products based on aerial conidia of entomopathogenic fungi, produced in solid fermentation, are widely used in the biological control of agricultural pests. However, very few products are based on submerged conidia and blastospores. The virulence of submerged conidia of the fungus Beauveria bassiana has not been demonstrated against the cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, two economically important pests in cotton and maize, respectively. Here we aimed to 1) Compare the production of submerged conidia and blastospores of six isolates of B. bassiana, 2) compare the virulence of submerged conidia, blastospores, and aerial conidia of three isolates against A. grandis and S. frugiperda and 3) to study the growth kinetics of an isolate in a 6-liter bioreactor. ESALQ2291, ESALQ3780, and ESALQ4238 produced 2 to 3 more blastospores than submerged conidia, and the production of the other isolates was similar. Blastospore yields ranged from 2.62 to 6.61 × 108 mL−1, and submerged conidia yields ranged from 1.88 to 3.92 × 108 mL−1 in culture flasks. The production phases of submerged conidia were defined in the bioreactor study, while the highest yield attained was 1.2 × 108 mL−1 after 108 h of culture. In general, blastospores and submerged conidia killed insects faster than aerial conidia for both insect species. Submerged conidia of isolate ESALQ3760 killed A. grandis adults faster than aerial conidia and blastospores of the same isolate. On the other hand, blastospores of isolate ESALQ4238 and ESALQ2291 killed S. frugiperda larvae faster than submerged and aerial conidia. This study revealed the potential of submerged conidia of B. bassiana against S. frugiperda and A. grandis, although, for most isolates, blastospore presented more significant biological parameters. This study reinforced the need to seek the proper propagule of the best isolate in developing biopesticides.

Damage Caused by Lepidopteran Pests on Maize Fields in Yamoussoukro, Central Côte d’Ivoire

Various larvae of Lepidoptera cause severe damage to maize crops. The dynamics of these maize larvae pests have been studied during all stages of plant development. The trial was carried out on the Institut National Polytechnique Houphouët-Boigny farm plots in Yamoussoukro (central Cote d’Ivoire). The study aims were to monitor the dynamics, determine the importance (frequency and abundance), and assess the damage of Lepidopteran pests on the maize variety EV8728 SR using a randomized complete block design with four replicates. The variety was sown on 05 September 2020. Insects were characterized with keys following on-site observation and capture of larvae on the plants. Five Lepidopteran species, grouped into three families, were counted on the plots. Spodoptera frugiperda was the most frequent (Occurrence C = 20.9%) and highly abundant (Relative Abundance Ar = 65.79%). The other Lepidoptera species were rare (C &lt; 5%). However, Sesamia calamistis was very abundant (Ar=15.22%), while Eldana saccharina (Ar = 9.44%) and Ostrinia nubilalis (Ar = 5.25%) were abundant. Helicoverpa zea is scarcely abundant (Ar=4.3%). Furthermore, three Lepidoptera species (E. saccharina, O. nubilalis, and H. zea) were as minor pests (Damage Index I &lt; 10%), while S. calamistis was important pest (I &lt; 25%) and S. frugiperda was major pest (I&lt; 75%). The populations of the insects fluctuated during crop development. The mean dried grain yield varied from 2.4±0.42 to 2.61±0.71 t/ha. Populations of S. frugiperda larvae and their damage appeared more important than those of other Lepidoptera. Knowledge of maize lepidopteran larvae is essential for effectively and efficiently controlling these pests and improving the quality and quantity of maize production.

The effects of carvacrol on development and gene expression profiles in Spodoptera frugiperda

The fall armyworm, Spodoptera frugiperda, is a highly polyphagous agricultural pest that is widely distributed around the world and causes severe crop yield loss. Carvacrol showed adverse effects on many pests, such as larval death and growth inhibition. While the effects of carvacrol on S. frugiperda larvae are not yet known. In this study, the effects of carvacrol on S. frugiperda, including larval growth inhibition and mortality induction, were observed. The detoxification and digestive enzyme activities of larvae with 1.0 and 2.0 g/kg carvacrol treatments were analyzed. Carvacrol boosted the enzyme activities of carboxylesterase (CarE) and glutathione S-transferase (GST) while decreasing the activities of α-amylase (AMS), lipase (LIP), and trypsin. A total of 3422 differentially expressed genes were identified in the larvae treated with 2.0 g/kg carvacrol, of which the DEGs involved in xenobiotic detoxification, food digestion, and insecticidal targets were further examined. These results suggest that carvacrol could regulate growth and development by affecting the process of food digestion, and exert its toxicity on the larvae through interaction with a variety of insecticidal targets. While the altered expressions of detoxification enzymes might be related to the detoxification and metabolism of carvacrol. Our findings offer a theoretical foundation for the use of carvacrol for S. frugiperda control in the field.

Comparative Genomics of Pesticide-Degrading Enterococcus Symbionts of Spodoptera frugiperda (Lepidoptera: Noctuidae) Leads to the Identification of Two New Species and the Reappraisal of Insect-Associated Enterococcus Species.

Enterococcus species have been described as core members of the microbial community of Spodoptera frugiperda (Lepidoptera: Noctuidae) and have been previously reported as insecticide degrading agents. This study aimed to investigate the molecular composition of these microbial symbionts of S. frugiperda to better understand their association with the host and their potential for insecticide metabolization. Through phenotypic assays and comparative genomic analyses of several pesticide-degrading Enterococcus isolated from the gut of S. frugiperda larvae, we identified two new species: Enterococcus entomosocium n. sp. and Enterococcus spodopteracolus n. sp. Their identities as new species were confirmed by whole genome alignment, utilizing cut-offs of 95-96% for the average nucleotide identity (ANI) and 70% for the digital DNA: DNA hybridization (dDDH) values. The systematic positioning of these new species within the genus Enterococcus was resolved using genome-based analysis, revealing Enterococcus casseliflavus as a sister group of E. entomosocium n. sp., and Enterococcus mundtii as a sister group of E. spodopteracolus n. sp. Comparative genomic analyses of several isolates of E. entomosocium n. sp. and E. spodopteracolus n. sp. provided a better assessment of the interactions established in the symbiotic association with S. frugiperda and led to the discovery of misidentified new species of Enterococcus associated with insects. Our analyses indicated that the potential of E. entomosocium n. sp. and E. spodopteracolus n. sp. to metabolize different pesticides arises from molecular mechanisms that result in rapid evolution of new phenotypes in response to environmental stressors, in this case, the pesticides their host insect is exposed to.

Eksplorasi, Identifikasi, dan Bioesai Jamur Entomopatogen terhadap Spodoptera frugiperda dari Kabupaten Purbalingga

The goals of this study were to explore and identify entomopathogenic fungi, as well as determine the most effective application techniques to control S. frugiperda from exploration of infected Spodoptera frugiperda larvae in Purbalingga Regency. The research was carried out at the Plant Protection Laboratory, Faculty of Agriculture, Jenderal Soedirman University, from January to May 2022. Samples were collected by purposive random method. The study used a Complete Randomized Design, consisting of two factors, namely the type of entomopathogenic fungus and the application technique, with 9 combinations and 3 replications. Observed variables include mortality, feeding activity, growth, and reproduction of larvae. The results showed that (1) the results of exploration of entomopathogenic fungi were from the genus Metarhizium sp. and Penicillium sp. (2) single treatment of Metarhizium sp. is more effective than Penicillium sp. in killing S. frugiperda larvae. Fungi Metarhizium sp. and Penicillium sp. decreased feeding activity, length of three-instar larval period, and number of eggs, respectively 24.99 and 15.99%, 4.71 and 2.46%, 9.18 and 8.04% against controls. (3) single treatment of feed soaking method decreased mortality by 55.18% than other methods. Spraying the larval body decreased mortality by 44.84% compared to other methods. The method of application did not affect the feeding, growth and fecundity activity of larvae. (4) The combined treatment of Metarhizium sp., spraying the larval body, and soaking feed had a mortality percentage of 60%. Interaction treatment of the fungus Metarhizium sp. and the method of application lowered the feed power by 16%. The decrease in the period of three instar larvae to pupae and the largest number of eggs in the combination treatment of Metarhizium sp. and spraying of larval bodies was 6.34% and 11.20% respectively compared to controls.&#x0D; &#x0D; Keywords: bioassay, entomopathogenic fungi, Spodoptera frugiperda, Purbalingga

Comparative analyses of the effects of sublethal doses of emamectin benzoate and tetrachlorantraniliprole on the gut microbiota of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Spodoptera frugiperda (J. E. Smith) is an important invasive pest that poses a serious threat to global crop production. Both emamectin benzoate (EB) and diamide insecticides are effective insecticides used to protect against S. frugiperda. Here, 16S rRNA sequencing was used to characterize the gut microbiota in S. frugiperda larvae exposed to EB or tetrachlorantraniliprole (TE). Firmicutes and Proteobacteria were found to be the dominant bacterial phyla present in the intestines of S. frugiperda. Following insecticide treatment, larvae were enriched for species involved in the process of insecticide degradation. High-level alpha and beta diversity indices suggested that exposure to TE and EB significantly altered the composition and diversity of the gastrointestinal microbiota in S. frugiperda. At 24 h post-EB treatment, Burkholderia-Caballeronia-Paraburkholderia abundance was significantly increased relative to the control group, with significant increases in Stenotrophobacter, Nitrospira, Blastocatella, Sulfurifustis, and Flavobacterium also being evident in these larvae. These microbes may play a role in the degradation or detoxification of EB and TE, although further work will be needed to explore the mechanisms underlying such activity. Overall, these findings will serve as a theoretical foundation for subsequent studies of the relationship between the gut microbiota and insecticide resistance in S. frugiperda (J. E. Smith) (Lepidoptera: Noctuidae).

Evaluation of Doru lineare (Dermaptera: Forficulidae) effectiveness against Spodoptera frugiperda (Lepidoptera: Noctuidae) and its potential protection of maize seedlings

The “fall armyworm”, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a significant pest of many crops, particularly maize. To control it, genetically modified plants and synthetic pesticides are the main strategies employed, which has led to the emergence of resistant populations to both methods. The earwig Doru lineare (Eschscholtz) (Dermaptera: Forficulidae) has been observed in Argentina consuming both eggs and early instars S. frugiperda larvae. To contribute to the implementation of a rational pest management system, field cage tests were conducted to assess the efficiency of D. lineare as a predator against S. frugiperda and its potential protection of maize seedlings from the pest. The results of the tests showed that the survival rate of S. frugiperda larvae was significantly affected by the presence of earwigs. When two earwigs were released into a cage containing ten maize seedlings infested with twenty S. frugiperda larvae, after ten days, the dry weight of the plants was significantly higher and the level of damage was significantly lower compared to those without earwig release. These results confirm the protective effect of D. lineare against S. frugiperda, suggesting that earwigs should be considered as promising predators in conservation control strategies for maize crops.

The several of Jengkol peel extract (Pithecellobium lobatum Benth) against corn armyworm (Spodoptera frugiperda J. E. Smith) in the laboratory

Spodoptera frugiperda J. E. Smith is an invasive insect that has become a pest on corn plants in Indonesia. S. frugiperda attacks maize plants from the vegetative to generative phases. Leaves of corn plants attacked by S. frugiperda larvae. with plant populations affected by 55-100% causing yield losses of 15-73%. The usual control is the use of synthetic insecticides, but the use of synthetic insecticides continuously or unwisely will have a negative impact on humans and the environment, therefore a safe and environmentally friendly alternative control using vegetable insecticides is jengkol plants (Pithecellobium lobate Benth). This study aims to obtain an effective concentration of jengkol bark extract to control armyworm pests Spodoptera frugiperda J.E. Smith in the laboratory. The study was conducted experimentally using a complete randomized design (RAL) consisting of five treatments with four repeats so that 20 experimental units were obtained. The concentration of jengkol bark extract used is 0 g.l-1 water, 25 g.l-1 water, 50 g.l-1 water, 75 g.l-1 water, and 100. g.l-1 water. The parameters observed were an initial time of death (hours), lethal time 50 (hours), lethal concentration (LC50 and LC95) (%), total mortality (%), temperature, and humidity. Jengkol bark extracts with a concentration of 100 g.l-1 water is an effective concentration in controlling corn plant pests (Spodoptera frugiperda J. E. Smith) in the laboratory because this concentration is able to cause total mortality of 90% with an initial time of death of 17.25 hours after application and lethal time of 50 at 60.75 hours after application.

Eurycomanone (EN) Activates Transcription Factor FoxO by Inhibiting the Insulin Signaling Pathway to Suppress the Development of Spodoptera frugiperda.

The insulin-like signaling (IIS) pathway is essential for insect growth and development. In this study, we showed that eurycomanone (EN) is an active compound with growth inhibitory activity against Spodoptera frugiperda larvae. Experiments in cells and RNA-seq analysis in the midgut showed that EN targeted the IIS pathway in S. frugiperda to activate the transcription factor SfFoxO (S. frugiperda forkhead boxO) to regulate mRNA levels associated with nutrient catabolism. Additionally, mass spectrometry imaging revealed that EN was distributed in the larval gut and enriched in the inner membrane of the gut. Immunofluorescence, western blotting, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) results showed that EN induced program cell death (PCD) in the larvae midgut. Thus, EN targeted the insulin receptor to inhibit the IIS signaling pathway, exerting inhibitory activity on the growth and development of S. frugiperda larvae. Our results suggest that EN has great potential as a botanical pesticide, and the IIS signaling pathway may be an effective target for botanical pesticides.

Identification and Characterization of Glutathione S-transferase Genes in Spodoptera frugiperda (Lepidoptera: Noctuidae) under Insecticides Stress.

Insect glutathione S-transferases (GSTs) serve critical roles in insecticides and other forms of xenobiotic chemical detoxification. The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a major agricultural pest in several countries, especially Egypt. This is the first study to identify and characterize GST genes in S. frugiperda under insecticidal stress. The present work evaluated the toxicity of emamectin benzoate (EBZ) and chlorantraniliprole (CHP) against the third-instar larvae of S. frugiperda using the leaf disk method. The LC50 values of EBZ and CHP were 0.029 and 1.250 mg/L after 24 h of exposure. Moreover, we identified 31 GST genes, including 28 cytosolic and 3 microsomal SfGSTs from a transcriptome analysis and the genome data of S. frugiperda. Depending on the phylogenetic analysis, sfGSTs were divided into six classes (delta, epsilon, omega, sigma, theta, and microsomal). Furthermore, we investigated the mRNA levels of 28 GST genes using qRT-PCR under EBZ and CHP stress in the third-instar larvae of S. frugiperda. Interestingly, SfGSTe10 and SfGSTe13 stood out with the highest expression after the EBZ and CHP treatments. Finally, a molecular docking model was constructed between EBZ and CHP using the most upregulated genes (SfGSTe10 and SfGSTe13) and the least upregulated genes (SfGSTs1 and SfGSTe2) of S. frugiperda larvae. The molecular docking study showed EBZ and CHP have a high binding affinity with SfGSTe10, with docking energy values of -24.41 and -26.72 kcal/mol, respectively, and sfGSTe13, with docking energy values of -26.85 and -26.78 kcal/mol, respectively. Our findings are important for understanding the role of GSTs in S. frugiperda regarding detoxification processes for EBZ and CHP.