Showing papers on "Lepidoptera genitalia published in 2022"
TL;DR: In this paper , the authors showed that GOBP2 plays an important role in perceiving sex pheromones in adult and larval stages, providing new insight into sex phrone perception and a potential target for sex phomone-based behavioral regulation in the pest.
18 citations
TL;DR: It is shown that reference to host strains is uninformative in the invasive populations because multidirectional introduction events likely underpinned its recent rapid spread and region-specific approaches will be needed to control this global pest.
Abstract: The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), is a well-known agricultural pest in its native range, North and South America, and has become a major invasive pest around the globe in the past decade. In this review, we provide an overview to update what is known about S. frugiperda in its native geographic ranges. This is followed by discussion of studies from the invaded areas to gain insights into S. frugiperda's ecology, specifically its reproductive biology, host plant use, status of insecticide resistance alleles, and biocontrol methods in native and invasive regions. We show that reference to host strains is uninformative in the invasive populations because multidirectional introduction events likely underpinned its recent rapid spread. Given that recent genomic analyses show that FAW is much more diverse than was previously assumed, and natural selection forces likely differ geographically, region-specific approaches will be needed to control this global pest. Expected final online publication date for the Annual Review of Entomology, Volume 68 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
15 citations
14 citations
TL;DR: In this paper , the authors investigated the insecticide resistance of Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) populations from five major cruciferous growing areas in Taiwan.
Abstract: The status of insecticide resistance levels is important for applying suitable pest management approaches. The present study investigated the insecticide resistance of Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) populations from five major cruciferous growing areas in Taiwan. The surveyed locations were distributed from central to southern Taiwan and included Taichung, Changhua, Yunlin, Chiayi, and Kaohsiung. High levels of resistance to spinosad, indoxacarb, metaflumizone, and chlorantraniliprole were recorded among the surveyed populations except in Taichung. The resistance ratios ranged from 2.376 to 1,236-fold for spinosad and 24.63-1,511-fold for indoxacarb. Similarly, those for metaflumizone and chlorantraniliprole, were 2.563-76.21- and 4.457-683.0-fold, respectively. However, Bacillus thuringiensis subsp. aizawai, Bacillus thuringiensis subsp. kurstaki, emamectin benzoate, and diafenthiuron were still relatively effective against most field populations of P. xylostella. After approximately 10 generations of being maintained in the laboratory without exposure to insecticides, the resistance ratios of the Kaohsiung and Changhua populations declined to approximately 1.4-10-fold, and insecticides with control failure likelihood also began to show a negligible risk of control failure. Although spinosad, indoxacarb, metaflumizone, and chlorantraniliprole have lost their effectiveness in most field populations of P. xylostella in Taiwan, their effectiveness may be recovered in the absence of insecticide-selection pressure for approximately 10 generations. Therefore, we suggest that a constant survey of insecticide resistance and well-designed insecticide rotation based on the survey results are necessary for the effective control and insecticide resistance management of P. xylostella.
14 citations
TL;DR: This is the first study to determine the sublethal concentrations of EMB on the life table parameters of two FAW generations and can provide important implications for the rational utilization of FAW insecticides.
Abstract: Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly invasive polyphagous pest that causes great economic losses to agricultural production. Emamectin benzoate (EMB) is one of the most popular biopesticides with high antipest, anti-parasitic and anti-nematode activities and low toxicity. The present study was conducted to determine the lethality of EMB to FAW for 24 h. Sublethal effects of EMB on FAW parental and offspring generations were also assessed. LC10, LC20 and LC50 EMB for 24 h on FAW third instar larvae were 0.0127 mg/L, 0.0589 mg/L, and 0.1062 mg/L, respectively. A low dose of sublethal concentrations of EMB could significantly influence the life cycle of FAW parental and offspring generations. Sublethal concentration (LC20) of EMB significantly prolonged the pupal period of male and increased the pupal weight of male but not of female, and significantly delayed the oviposition period and longevity of adult FAW. In the FAW offspring generation, sublethal concentrations significantly increased the mortality of offspring pupae and pre-adults, and reduced the development time of offspring larvae and pre-adult male and female. Sublethal concentrations (LC10 and LC20) of EMB significantly decreased the FAW oviposition period. However, only LC10 significantly reduced FAW F1 female fecundity. No significant difference was found in the intrinsic rates of natural increase (rm), finite rate of population increase (λ), and net reproductive rate (R0) of FAW offspring exposed to sublethal concentrations. This is the first study to determine the sublethal concentrations of EMB on the life table parameters of two FAW generations. These findings can provide important implications for the rational utilization of FAW insecticides.
13 citations
TL;DR: In this paper , the authors conducted life table analyses and assessed both proteolytic and amylolytic activities of S. littoralis larvae on 11 common legume cultivars.
Abstract: Simple Summary Spodoptera littoralis (Boisd) is a highly polyphagous and destructive pest, which attacks a wide range of economically important crops throughout the world. The extensive use of conventional insecticides for management of S. littoralis has resulted in development of resistance to major classes of pesticides and can have a negative impact on the environment. It is necessary to investigate alternative pest management approaches that are more cost-effective and sustainable than conventional insecticides. The aim of this study was to identify potential sources of variation in resistance/susceptibility of legume cultivars to S. littoralis, and to describe potential interactions between cultivar traits and digestive function of this pest. We conducted life table analyses and assessed both proteolytic and amylolytic activities of S. littoralis on 11 common legume cultivars. The findings indicated that S. littoralis reared on the common bean, Arabi, displayed the highest intrinsic rate of increase, while the lowest was recorded on the cowpea, Mashhad. Developmental time of S. littoralis larvae was negatively correlated with protein content, while amylolytic activity was positively correlated with starch content of legumes. Our results revealed that the Mashhad cultivar exhibited tolerance traits against S. littoralis, which may prove useful for integrated programs that aim to reduce chemical inputs. Abstract Spodoptera littoralis (Boisd) is a highly destructive pest that attacks a large number of economically important crops. We examined life table parameters as well as activity of major digestive enzymes of S. littoralis larvae in response to protein and starch contents across 11 legume cultivars to identify potential resistance traits. The results showed that S. littoralis reared on the common bean, Arabi, displayed the highest intrinsic rate of increase (r), while the lowest was recorded on the cowpea, Mashhad. Also, the highest net reproductive rate (R0) was obtained in those insects reared on the Arabi cultivar. Larvae displayed the highest and lowest proteolytic activities when fed on Mashhad and Arabi cultivars, respectively. The highest amylolytic activity was quantified in larvae that fed on the Arabi and 1057 cultivars, while the lowest occurred in larvae feeding on Yaghout and Mashhad cultivars. Developmental time of S. littoralis larvae was negatively correlated with protein content, while amylolytic activity was positively correlated with starch content of legumes. Our findings indicate that Arabi was a susceptible cultivar, while Mashhad exhibited tolerance traits against S. littoralis. These results should facilitate selection of legume cultivars for production or breeding efforts that involve S. littoralis management.
12 citations
TL;DR: It is demonstrated that combining botanicals with synthetic insecticides can synergize their toxicity against S. frugiperda larvae, suggesting their potential incorporation into future IPM programs against S .
Abstract: Fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), is a destructive pest of a wide array of agricultural and horticultural crops worldwide. This in vitro research assessed the combined effect of methanolic extracts of indigenous flora of Soone Valley (Khushab, Pakistan) and nine commonly used synthetic insecticides against 3rd instar larvae of S. frugiperda using the leaf-dip bioassay method. Toxicity bioassays with twelve plant extracts revealed that the extracts of Withania somnifera (L.) Dunal, Sophora mollis (Royle) Baker and Rhazya stricta Decne. were the most effective, exhibiting minimum LC50 and LT50 values. Bioassays with synthetic insecticides revealed a significantly higher mortality of S. frugiperda larvae by emamectin benzoate (45%), chlorpyrifos (40%) and chlorantraniliprole (38%). Further bioassays with 10 binary combinations of these most effective botanical and synthetic insecticides showed that seven pesticidal combinations exhibited synergistic toxicity, and three combinations comprising emamectin benzoate exhibited an additive effect on the mortality of S. frugiperda larvae. GC–MS analyses of methanolic extracts of W. somnifera, S. mollis and R. stricta revealed 1,2,4-trimethyl-benzene and 3,5-dimethyl-octane, 1-ethyl-2-methyl-benzene, and 1-monolinoleoylglycerol trimethylsilyl ether, decane, and lupeol as major bioconstituents, respectively. Our results demonstrated that combining botanicals with synthetic insecticides can synergize their toxicity against S. frugiperda larvae, suggesting their potential incorporation into future IPM programs against S. frugiperda and other lepidopterous pests.
12 citations
TL;DR: A review of the existing knowledge of what have been focused so far on published materials related to AMPs isolated from insects is presented in this article , where a variety of insect Orders are compared: Hymenoptera (50%), Diptera (17%), Coleoptera, Lepidoptera and Odonata.
Abstract: Antimicrobial peptides (AMPs) in insects have the potential to be developed as chemotherapy agents against numerous microbial species. This article reviewed the existing knowledge of what have been focused so far on published materials related to AMPs isolated from insects. Previous studies were focused on peptide characterization and the mechanism pathways of different AMPs from a variety of insect Orders. Most studied insect Orders are as follows: Hymenoptera (50%), Diptera (17%), Coleoptera (13%), Lepidoptera (10%), Hemiptera (5%), Blattodea (3%) and Odonata (2%). Dozens of new AMPs have been extracted from insects recently. However, more studies in vivo and in vitro are necessary to fully understand their effect and the mechanisms of antimicrobial action to utilize their promising potential in cosmetic and pharmaceutical industries.
12 citations
TL;DR: Five PRs are deorphanized and four types of sensilla responsible for the detection of pheromone compounds are characterized, providing insights into the peripheral encoding of sex phersomones in S. frugiperda.
Abstract: BACKGROUND
The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a polyphagous moth species and spreading all around the globe. It uses (Z)-9-tetradecenyl acetate (Z9-14:Ac) and (Z)-7-dodecenyl acetate (Z7-12:Ac) (100:3.9) as essential sex pheromone components. However, our understanding of the molecular basis of pheromone detection of S. frugiperda is still incomplete.
RESULTS
Herein, we identified six PRs, i.e. SfruOR6, 11, 13, 16, 56, and 62, by transcriptome sequencing. Subsequently, we heterologously expressed them in Drosophila OR67d neurons and determined their response spectra with a big panel of sex pheromones and analogs. Among them, SfruOR13-expressing neurons strongly respond to the major sex pheromone component, Z9-14:Ac, but also comparably to (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac) and weakly to (Z)-9-dodecenyl acetate (Z9-12:Ac). Both SfruOR56 and SfruOR62 are specifically tuned to the minor sex pheromone component, Z7-12:Ac with varying intensities and sensitivities. In addition, SfruOR6 is activated only by Z9,E12-14:Ac, and SfruOR16 by both (Z)-9-tetradecenol (Z9-14:OH) and (Z)-9-tetradecenal (Z9-14:Ald). However, the OR67d neurons expressing SfruOR11 remain silent to all compounds tested, a phenomenon commonly found in the OR11 clade of Noctuidae species. Next, using single sensillum recording, we characterized three sensilla types on the antennae of males, namely A, B, C and D types that are tuned to the ligands of PRs, thereby confirming that S. frugiperda uses both SfruOR56 and SfruOR62 to detect Z7-12:Ac. Last, using wind tunnel assay, we demonstrate that both Z9,E12-14:Ac and Z9-14:OH act as antagonists to the sex pheromone.
CONCLUSION
We have deorphanized five PRs and characterized four types of sensilla responsible for the detection of pheromone compounds, providing insights into the peripheral encoding of sex pheromones in S. frugiperda.
12 citations
12 citations
TL;DR: In this paper , a Wolbachia protein, designated Oscar, was identified to interact with the host factor Masculinizer via its ankyrin repeats, which led to male killing in two lepidopteran insects, Ostrinia furnacalis and Bombyx mori.
Abstract: Abstract Bacterial symbionts, such as Wolbachia species, can manipulate the sexual development and reproduction of their insect hosts. For example, Wolbachia infection induces male-specific death in the Asian corn borer Ostrinia furnacalis by targeting the host factor Masculinizer (Masc), an essential protein for masculinization and dosage compensation in lepidopteran insects. Here we identify a Wolbachia protein, designated Oscar, which interacts with Masc via its ankyrin repeats. Embryonic expression of Oscar inhibits Masc-induced masculinization and leads to male killing in two lepidopteran insects, O. furnacalis and the silkworm Bombyx mori . Our study identifies a mechanism by which Wolbachia induce male killing of host progeny.
TL;DR: In this article , a comprehensive Nudiviridae phylogeny was provided by including recently described nudiviral isolates, and discussed this phylogeny in comparison to current opinions and taxonomical propositions.
TL;DR: In this paper , the authors identified a repertoire of 26 IRs from transcriptomes of female and male antennae, and ovipositors in the moth Agrotis segetum, and demonstrated that the five IRs and their co-receptors are not located in coeloconic sensilla as found in Drosophila, but in basiconic or trichoid sensilla.
Abstract: In insects, airborne chemical signals are mainly detected by two receptor families, odorant receptors (ORs) and ionotropic receptors (IRs). Functions of ORs have been intensively investigated in Diptera and Lepidoptera, while the functions and evolution of the more ancient IR family remain largely unexplored beyond Diptera.Here, we identified a repertoire of 26 IRs from transcriptomes of female and male antennae, and ovipositors in the moth Agrotis segetum. We observed that a large clade formed by IR75p and IR75q expansions is closely related to the acid-sensing IRs identified in Diptera. We functionally assayed each of the five AsegIRs from this clade using Xenopus oocytes and found that two receptors responded to the tested ligands. AsegIR75p.1 responded to several compounds but hexanoic acid was revealed to be the primary ligand, and AsegIR75q.1 responded primarily to octanoic acid, and less so to nonanoic acid. It has been reported that the C6-C10 medium-chain fatty acids repel various insects including many drosophilids and mosquitos. We show that the C6-C10 medium-chain fatty acids elicited antennal responses of both sexes of A. segetum, while only octanoic acid had repellent effect to the moths in a behavioral assay. In addition, using fluorescence in situ hybridization, we demonstrated that the five IRs and their co-receptor AsegIR8a are not located in coeloconic sensilla as found in Drosophila, but in basiconic or trichoid sensilla.Our results significantly expand the current knowledge of the insect IR family. Based on the functional data in combination with phylogenetic analysis, we propose that subfunctionalization after gene duplication plays an important role in the evolution of ligand specificities of the acid-sensing IRs in Lepidoptera.
TL;DR: In this paper , the effects of three different temperatures (20, 25, and 30 °C) and three different host plants (maize (Zea mays L. (Poaceae)), sorghum (Sorghum bicolor (L.) Moench), and coix seed (Coix lacryma-jobi L.).
Abstract: Simple Summary Fall armyworm (FAW), Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) is an invasive worldwide agricultural pest that seriously threatens the safety of grain production. Temperatures and hosts play vital roles in the performance of S. frugiperda. In this study, we studied the effects of three different temperatures (20, 25, and 30 °C) and three different host plants (maize (Zea mays L. (Poaceae)), sorghum (Sorghum bicolor (L.) Moench), and coix seed (Coix lacryma-jobi L.)) on the whole life cycle of S. frugiperda. The results showed that both temperatures and host plants significantly influenced the mortality, developmental time, reproduction, and population parameters of FAW. In the treatment with host plants, the developmental period of S. frugiperda at each stage shortened significantly with the increasing of temperatures. At each temperature, the type of host plant did not affect the development time of S. frugiperda eggs. However, there was no significant difference when S. frugiperda 1st to 6th instar larvae were fed different host plants at 20 °C, while 2nd to 5th instar larvae developed rapidly on maize at 25 and 30 °C. Moreover, there were no significant differences in the longevity of FAW when fed sorghum and coix seed at 20 and 25 °C, but a significant difference in the longevity was observed at 30 °C. Feeding on maize achieved a higher intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) of S. frugiperda at 25 and 30 °C than those FAW fed on sorghum and coix seed. Abstract The interactions between ambient temperatures and host plants are central to the population dynamics of invasive animal species. Despite significant research into the effects of temperatures, the performance of invasive species is also influenced by host plants. The effects of different temperatures (20, 25, and 30 °C) and host plants (maize, sorghum, and coix seed) were tested on the mortality, development, reproduction, and population parameters of the fall armyworm (FAW), Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae), using an age-stage, two-sex life table. The results support the hypothesis that temperature and the species of the host plant significantly influences the performance of FAW. Feeding on maize at 30 °C resulted in a lower mortality rate, a shorter developmental time and longevity, a higher fecundity, intrinsic rate of natural increase (r), finite rate of increase (λ), and net reproductive rate (R0). However, at 20 °C, the host plant could eliminate temperature-mediated synergism in FAW performance, which did not reach statistical significance at 20 °C. Similar results induced by a relatively low temperature (20 °C) on different host plants were also found in the age-stage specific survival curves (sxj), fecundity (mx), maternity (lxmx), and reproductive value (vxj) curves of FAW. Consequently, we also need to pay more attention to FAW outbreaks on different host plants mediated by relatively low temperatures.
TL;DR: The Geometridae portal as discussed by the authors provides access to the global database including data on classification, valid genera and species, synonyms and type localities, and an online list of valid names.
Abstract: Abstract We present a new, online, open access portal to the geometrid moths of the world (Lepidoptera: Geometridae). The portal provides access to the global database including data on classification, valid genera and species, synonyms and type localities, and to an online list of valid names. The value of this online facility, inter alia, is demonstrated by using the underlying data to update our understanding of the global and regional species richness of the family. We also review, clarify and list the family-group names (family, subfamily, tribe) of the Geometridae to provide users with a better understanding of the higher category framework when they access the database. Currently, the Geometridae database includes 34,897 available species-group names. Of these, 7,891 are considered synonyms (23% of available names), giving a total of 27,006 valid species-group names, which in turn comprise 23,872 species names and 3,134 subspecies names. The world fauna is classified into 2,019 genera, 92 tribes and 9 subfamilies. Our paper also includes an annotated list of all 202 subfamily, tribe and subtribe names in systematic order. One hundred family-group names (49.5%) are considered synonyms. Although most geometrid species were described in the 19th and 20th centuries, the average number of new species descriptions from 2000–2022 has been fairly constant at around 80 per year, implying there is still much more hidden geometrid diversity yet to be discovered. Zusammenfassung Ein neues, frei zugängliches Online-Portal zu den Geometriden der Welt (Lepidoptera: Geometridae) wird hier vorgestellt. Das Portal bietet Zugang zu einer globalen Datenbank mit Informationen zur Klassifikation, zu sämtlichen validen Gattungs- und Artnamen, Synonymen und Typuslokalitäten. Die Bedeutung dieser öffentlich zugänglichen Datensammlung liegt darin, unsere Kenntnisse über den globalen und regionalen Artenreichtum der Familie Geometridae zu verbessern. Außerdem wurden die Namen der höherrangigen Taxa (Familie, Unterfamilie, Tribus) überarbeitet, ihr Status geklärt und aufgelistet, um den Benutzern ein besseres Verständnis der Phylo-genie nach dem augenblicklichen Stand der Forschung zu vermitteln. Derzeit umfasst die Familie der Geometriden 23.872 beschriebene und valide Arten und 3.134 validierte Unterarten, während weitere 7.891 Namen als Synonyme betrachtet werden (23 % der verfügbaren Namen). Die weltweite Fauna ist in 2.019 Gattungen, 92 Triben und 9 Unterfamilien unterteilt. Unsere Arbeit enthält zudem eine kommentierte Liste aller 202 Unterfamilien-, Tribusund Subtribusnamen in systematischer Reihenfolge. 100 dieser Namen (49,5 %) werden als Synonyme betrachtet. Während die meisten Geometriden-Arten im 19. und 20. Jahrhundert beschrieben wurden, liegt die durchschnitt-liche Zahl der neuen Artbeschreibungen von 2000 bis 2022 ziemlich konstant bei etwa 80 pro Jahr, was bedeutet, dass eine bedeutende Zahl von Geometriden noch darauf wartet, entdeckt zu werden.
TL;DR: In this article , a second clade of pheromone receptors has been identified for the E. postvittana ('Epos') moth, which includes the receptor for (E)-11-tetradecenyl acetate (EposOR30).
TL;DR: This work found that compound 2a not only resulted in 22.1% of malformed moths with vestigial wings but also significantly decreased the fecundity of Vestigial-winged female moths in the P generation.
Abstract: Unlike faster-acting conventional insecticides, some botanical insecticides exhibit growth inhibitory activity against some insect pests. One of the distinguishing features of growth inhibitory activity appears to be in malformed moths with vestigial wings. However, the molecular mechanism underlying vestigial wings of insect pests induced by plant natural products or their derivatives is still elusive. In this work, based upon the phenotype of the vestigial wings of Mythimna separata Walker (as a model pest) induced by a podophyllotoxin derivative 2a (as a model compound), we found that compound 2a not only resulted in 22.1% of malformed moths with vestigial wings but also significantly decreased the fecundity of vestigial-winged female moths in the P generation; the trait of vestigial wings caused by 2a in the P generation can be inherited by the F1 generation; compound 2a may target insulin receptor 1 (InR1), suppress the InR1 mRNA level, and block InR1-pY1229 and InR1-pY1233/1234 phosphorylation levels in a tissue-specific manner "head/thorax/wing tissues". Notably, compound 2a can also induce the vestigial wings of Spodoptera frugiperda (another seriously harmful migratory lepidoptera pest). It is noteworthy that this insect insulin receptor can be used as a new kind of target receptors for the design of novel green insecticides.
TL;DR: The results suggest that alternative host plants, such as potato and rice, have more effect on reproduction than the growth of corn strain FAW, and may be useful in predicting the population dynamics of FAW and understanding the potential damage to crops, thus contributing to an appropriate management strategy in the newly FAW-invaded agricultural ecosystems.
Abstract: Simple Summary Since 2016, the fall armyworm (FAW), an invasive pest native to tropical and subtropical regions of the Americas, has invaded Africa and further spread into Asian countries. FAW is a polyphagous species, although the invaded strain mostly damages corn rather than any other host plants. Studies on the biology of corn strain FAW reared on three different host plants: corn, rice, and potato, using the age-stage, two-sex life table, showed that growth, development, survival, and reproduction rate of the corn strain FAW were differentially affected by rice and potato host plants. The reproduction rate was highly affected than other parameters such as growth, development, survival rates. Our results provide important information for the understanding of the population dynamics of FAW and an appropriate management strategy in the newly FAW-invaded agricultural ecosystems. Abstract The fall armyworm (FAW), Spodoptera frugiperda, is an invasive pest species that has recently increased its range in most African and Asian countries, causing significant losses to crop yields, especially corn. To develop effective management strategies, it is particularly important to study the biology of FAW in various crops. Here, we utilized the age-stage, two-sex life table to examine the development, survival, and reproduction rate of the corn strain FAW on three different host plants: corn, rice, and potato. The corn strain FAW successfully completed its life cycle in rice and potato, as well as corn plants. However, the growth, developmental time, survival, and reproduction rate differed among the three host plants. The preadult survival rates in corn, rice, and potato were 92%, 81%, and 77%, respectively. Similarly, mean generation time was significantly shorter in corn (35 days), followed by rice (41 days) and potato (42 days), indicating more generations in corn. Interestingly, the net reproduction rate varied greatly among the three host plants. In corn-fed FAW, the net reproduction rate was 472 offspring per individual, whereas, in rice and potato crops, the rates were only 213 and 86 offspring per individual, respectively. Our results suggest that alternative host plants, such as potato and rice, have more effect on reproduction than the growth of corn strain FAW. These results may be useful in predicting the population dynamics of FAW and understanding the potential damage to crops, thus contributing to an appropriate management strategy in the newly FAW-invaded agricultural ecosystems.
TL;DR: A review on T. remus mass rearing techniques, estimated costs of mass production, and release strategies is presented in this article , which provides good opportunities for the establishment of an augmentative biological control program, reinforcing sustainable production of major maize in affected countries.
Abstract: Abstract Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae), also known as fall armyworm (FAW) is a polyphagous pest which can cause significant losses and is considered a global threat to different crops and a risk to food security. Currently, in maize, the pest is predominantly controlled by pesticides or transgenic events. However, the use of biological control agents is considered the most sustainable and preferred method of control, providing high effectiveness. Among the various natural enemies reported for FAW, the egg parasitoid Telenomus remus has gained most interest, and has been mass released against FAW in the Americas for many years. In addition to FAW, other armyworms of the genus Spodoptera often cause high crop damage and may be controlled using T. remus . Among other important aspects, this paper presents a review on T. remus mass rearing techniques, estimated costs of mass production, and release strategies. Due to the recent invasion of FAW in Africa, Asia, and Australia T. remus provides good opportunities for the establishment of an augmentative biological control program, reinforcing sustainable production of major crops such as maize in affected countries.
TL;DR: Experiments suggest H. indica 1 NBAIIH38 to be a promising biocontrol agent against S. frugiperda in maize production and Emamectin benzoate was more effective in reducing the larval population compared to EPNs species.
Abstract: BACKGROUND
The occurrence of Spodoptera frugiperda (J.E. Smith) in Asia was reported for the first time from Karnataka in 2018. This pest is widely distributed in India, causing significant damage to maize. Management of this recent invasive pest in maize growing regions of India relies upon chemical control. Resistance is the greatest obstacle to the successful use of chemical insecticides to control this pest. Indiscriminate use of chemical insecticides destroys beneficial natural enemies. Therefore effective and sustainable alternative control strategies are needed. In this case, the use of biological control agents is the alternative option to mitigate this pest. Thus, this study aimed to select virulent entomopathogenic nematodes (EPN) isolates based on the laboratory assay and further to test the efficacy of virulent isolates in the field condition along with commonly used chemical insecticide emamectin benzoate against S. frugiperda.
RESULTS
Laboratory results revealed that both Heterorhabditis indica 1 NBAIIH38 and Steinernema carpocapsae NBAIRS59 caused 100% mortality in third- and fourth-instar larvae of S. frugiperda, while these two species caused 82.5 and 75.0% mortality in pupae, respectively. When pupae of S. frugiperda were exposed to EPNs, pupae died after metamorphosis to malformed adult. All the nematode species were able to penetrate and reproduce within S. frugiperda larvae, but the reproduction rate for Heterorhabditids was higher than those of Steinernematids. Field trial results showed that H. indica 1 NBAIIH38 significantly reduced the number of larvae and leaf damage scores than S. carpocapsae NBAIRS59. Emamectin benzoate was more effective in reducing the larval population compared to EPNs species. The cob yield was significantly higher in EPN-and emamectin benzoate-treated plots than untreated control plots.
CONCLUSION
Overall, these experiments suggest H. indica 1 NBAIIH38 to be a promising biocontrol agent against S. frugiperda in maize production. This article is protected by copyright. All rights reserved.
TL;DR: In this article , the authors integrated 794 mitogenomes consisting of 37 genes and a noncoding control region, which covered 26 lepidopteran superfamilies from newly sequenced and publicly available genomes for comparative genomic and phylogenetic analysis.
TL;DR: The introduction of fall armyworm (FAW) Spodoptera frugiperda (JE Smith) on the African continent has led to paradigm shifts in pest control in maize systems, occasioned by year-round populations as discussed by the authors .
Abstract: The introduction of fall armyworm (FAW) Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) on the African continent has led to paradigm shifts in pest control in maize systems, occasioned by year-round populations. The discovery of resident parasitoid species adapting to the new pest significantly informed decision-making toward avoiding highly hazardous synthetic insecticides to control the pest. A number of biopesticides have shown promise against the fall armyworm, providing a new arsenal for the sustainable management of this invasive pest. However, a few knowledge gaps remain for a fully integrated and sustainable FAW-management approach, particularly on host-resistance potential.
TL;DR: In this article , the authors determined the resistance allele frequency (RAF) to Cry1Ab and Vip3Aa20 in H. zea populations that were collected during 2018 and 2019 from four southeastern U.S. states: Louisiana, Mississippi, Georgia, and South Carolina.
Abstract: The corn earworm/bollworm, Helicoverpa zea (Boddie), is a pest species that is targeted by both Bacillus thuringiensis (Bt) maize and cotton in the United States. Cry1Ab and Vip3Aa20 are two common Bt toxins that are expressed in transgenic maize. The objective of this study was to determine the resistance allele frequency (RAF) to Cry1Ab and Vip3Aa20 in H. zea populations that were collected during 2018 and 2019 from four southeastern U.S. states: Louisiana, Mississippi, Georgia, and South Carolina. By using a group-mating approach, 104 F2 iso-lines of H. zea were established from field collections with most iso-lines (85) from Louisiana. These F2 iso-lines were screened for resistance alleles to Cry1Ab and Vip3Aa20, respectively. There was no correlation in larval survivorship between Cry1Ab and Vip3Aa20 when the iso-lines were exposed to these two toxins. RAF to Cry1Ab maize was high (0.256) and the RAFs were similar between Louisiana and the other three states and between the two sampling years. In contrast, no functional major resistance allele (RA) that allowed resistant insects to survive on Vip3Aa20 maize was detected and the expected RAF of major RAs with 95% probability was estimated to 0 to 0.0073. However, functional minor RAs to Vip3Aa20 maize were not uncommon; the estimated RAF for minor alleles was 0.028. The results provide further evidence that field resistance to Cry1Ab maize in H. zea has widely occurred, while major RAs to Vip3Aa20 maize are uncommon in the southeastern U.S. region. Information that was generated from this study should be useful in resistance monitoring and refinement of resistance management strategies to preserve Vip3A susceptibility in H. zea.
TL;DR: An optimized pheromone blend of Z9-14:Oac, Z7-12:OAc, and Z11-16:O Ac in a 88:1:11 ratio is identified for monitoring the invasive pest S. frugiperda in China.
Abstract: BACKGOUND
Sex pheromones of the fall armyworm, Spodoptera frugiperda, show differences in composition and proportions in different geographical populations, but always contain Z9-14:OAc as the major component. Odorant receptor neurons (ORNs) housed in the long trichoid sensilla (TS) of male antennae are essential to detect female-released sex pheromones in moths.
RESULTS
In this study, we identified seven components from pheromone gland extracts of female S. frugiperda in the Yunnan population from China., including (Z)-7-dodecen-1-yl acetate (Z7-12:OAc), (Z)-9-tetradecenal (Z9-14:Ald), (Z)-9-dodecen-1-yl acetate (Z9-12:OAc), (Z)-9-tetradecen-1-yl acetate (Z9-14:OAc), (E)-11-tetradecen-1-yl acetate (E11-14:OAc), (Z)-11-tetradecen-1-yl acetate (Z11-14:OAc), and (Z)-11-hexadecen-1-yl acetate (Z11-16:OAc) at a ratio of 1.2:4:0.8:79.1:1.6:1.6:11.7 by gas chromatography coupled with mass spectrometry. Gas chromatography-electroantennographic detection showed that Z9-14:OAc, Z7-12:OAc, and Z11-16:OAc are the male antennal active components. Peripheral coding of pheromones in males is investigated by single sensillum recording. Five functional neurons housed in three types of TS are identified based on profiles of neuronal responses, which are responsible for attractive component Z9-14:OAc, synergistic components Z7-12:OAc, Z11-16:OAc, interspecific pheromones (Z)-9-tetradecen-1-ol (Z9-14:OH) and (Z,E)-9,12-tetradecadien-1-yl acetate (Z9,E12-14:OAc), respectively. Wind tunnel and field tests demonstrated that ternary combination of Z9-14:OAc, Z7-12:OAc, and Z11-16:OAc at the ratio of 88:1:11 shows the strongest attractiveness to males.
CONCLUSION
An optimized pheromone blend of Z9-14:OAc, Z7-12:OAc, and Z11-16:OAc in a 88:1:11 ratio is identified for monitoring the invasive pest S. frugiperda in China. Five functional ORNs encoding intra- and interspecific pheromones are identified in male antennae, of which, three neurons encode attractive component Z9-14:OAc, synergistic components Z7-12:OAc and Z11-16:OAc, respectively, and the other two neurons encode interspecific pheromones Z9-14:OH and Z9,E12-14:OAc, separately. This article is protected by copyright. All rights reserved.
TL;DR: In this article , a loop-mediated isothermal amplification (LAMP) based on the mitochondrial cytochrome c oxidase subunit I (COI) gene was developed for accurate and timely diagnosis of fall armyworm (FAW) in the field.
Abstract: Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly polyphagous invasive plant pest that has expanded its global geographic distribution, including recently into much of Australia. Rapid diagnostic tests are required for identification of FAW to assist subsequent management and control. We developed a new loop-mediated isothermal amplification (LAMP) assay based on the mitochondrial cytochrome c oxidase subunit I (COI) gene for accurate and timely diagnosis of FAW in the field. The specificity of the new assay was tested against a broad panel of twenty non-target noctuids, including eight other Spodoptera species. Only S. frugiperda samples produced amplification within 20 min, with an anneal derivative temperature of 78.3 ± 0.3 °C. A gBlock dsDNA fragment was developed and trialled as a synthetic positive control, with a different anneal derivative of 81 °C. The new FAW LAMP assay was able to detect FAW DNA down to 2.4 pg, similar to an existing laboratory-based real-time PCR assay. We also trialled the new FAW assay with a colorimetric master mix and found it could successfully amplify positive FAW samples in half the time compared to an existing FAW colorimetric LAMP assay. Given the high sensitivity and rapid amplification time, we recommend the use of this newly developed FAW LAMP assay in a portable real-time fluorometer for in-field diagnosis of FAW.
TL;DR: The European Spongy moth, Lymantria dispar, is an abundant species found in oak woods in Central and Southern Europe, the Near East, and North Africa and is an important economic pest.
Abstract: Simple Summary In the current review, we gathered and summarized the up-to-date information on the life cycle, distribution, outbreaks, control, and health issues to humans and animals of the European Spongy moth. Overall, this noxious species is easily expanded to new areas, causing serious large-scale damage rapidly. The management of this insect is difficult since the chemicals are harmful to human health and the environment, and natural enemies are not able to cause sufficient reduction of the populations of L. dispar. Finally, the potential use of biotechnological and physical methods against L. dispar is discussed. Abstract The European Spongy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is an abundant species found in oak woods in Central and Southern Europe, the Near East, and North Africa and is an important economic pest. It is a voracious eater and can completely defoliate entire trees; repeated severe defoliation can add to other stresses, such as weather extremes or human activities. Lymantria dispar is most destructive in its larval stage (caterpillars), stripping away foliage from a broad variety of trees (>500 species). Caterpillar infestation is an underestimated problem; medical literature reports that established populations of caterpillars may cause health problems to people and animals. Inflammatory reactions may occur in most individuals after exposure to setae, independent of previous exposure. Currently, chemical and mechanical methods, natural predators, and silvicultural practices are included for the control of this species. Various insecticides have been used for its control, often through aerial sprayings, which negatively affect biodiversity, frequently fail, and are inappropriate for urban/recreational areas. However, bioinsecticides based on various microorganisms (e.g., entomopathogenic viruses, bacteria, and fungi) as well as technologies such as mating disruption using sex pheromone traps have replaced insecticides for the management of L. dispar.
TL;DR: In this article , a loop-mediated isothermal amplification (LAMP) based on the mitochondrial cytochrome c oxidase subunit I (COI) gene was developed for accurate and timely diagnosis of fall armyworm (FAW) in the field.
Abstract: Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly polyphagous invasive plant pest that has expanded its global geographic distribution, including recently into much of Australia. Rapid diagnostic tests are required for identification of FAW to assist subsequent management and control. We developed a new loop-mediated isothermal amplification (LAMP) assay based on the mitochondrial cytochrome c oxidase subunit I (COI) gene for accurate and timely diagnosis of FAW in the field. The specificity of the new assay was tested against a broad panel of twenty non-target noctuids, including eight other Spodoptera species. Only S. frugiperda samples produced amplification within 20 min, with an anneal derivative temperature of 78.3 ± 0.3 °C. A gBlock dsDNA fragment was developed and trialled as a synthetic positive control, with a different anneal derivative of 81 °C. The new FAW LAMP assay was able to detect FAW DNA down to 2.4 pg, similar to an existing laboratory-based real-time PCR assay. We also trialled the new FAW assay with a colorimetric master mix and found it could successfully amplify positive FAW samples in half the time compared to an existing FAW colorimetric LAMP assay. Given the high sensitivity and rapid amplification time, we recommend the use of this newly developed FAW LAMP assay in a portable real-time fluorometer for in-field diagnosis of FAW.
TL;DR: In this article , a bulk DNA extraction method was designed for the detection of Phthorimaea absoluta Meyrick (Lepidoptera: Gelechiidae), an invasive moth that can decimate tomato crops.
Abstract: Invasive insects can cause catastrophic damage to ecosystems and cost billions of dollars each year due to management expenses and lost revenue. Rapid detection is an important step to prevent invasive insects from spreading, but improvements in detection capabilities are needed for bulk collections like those from sticky traps. Here we present a bulk DNA extraction method designed for the detection of Phthorimaea absoluta Meyrick (Lepidoptera: Gelechiidae), an invasive moth that can decimate tomato crops. We test the extraction method for insect specimens on sticky traps, subjected to different temperature and humidity conditions, and among mock insect communities left in the field for up to 21 d. We find that the extraction method yielded high success (>92%) in recovering target DNA across field and lab trials, without a decline in recovery after three weeks, across all treatments. These results may have a large impact on tomato growing regions where P. absoluta is in the early stages of invasion or not yet present. The extraction method can also be used to improve detection capabilities for other bulk insect collections, especially those using sticky traps, to the benefit of pest surveys and biodiversity studies.
TL;DR: In this paper , the authors review the history of insecticide resistance in S. frugiperda and discuss the influence that life history traits, migration ecology, and chemical control practices may have on control efficacy and resistance evolution.
Abstract: Abstract Insecticides and genetically modified Bt crops are the main tools for control of the fall armyworm, Spodoptera frugiperda (J.E. Smith). Since its invasion of Africa, the Far East, and Australia where Bt crops are largely absent, insecticide use has increased and reduced susceptibility to several insecticides used for decades in its native distribution area have been reported. Poor efficacy at field-level is sometimes incorrectly ascribed to pest resistance, while numerous other factors influence efficacy at field-level. In this paper, we review the history of insecticide resistance in S. frugiperda and discuss the influence that life history traits, migration ecology, and chemical control practices may have on control efficacy and resistance evolution. The indirect role that poor national policies have on pesticide use practices, and indirectly on control efficacy and selection pressure is discussed. Evidence shows that local selection for resistance drives resistance evolution. Integrated pest management, rather than reliance on a single tactic, is the best way to suppress S. frugiperda numbers and the over-use of insecticides which selects for resistance.