scholarly journals Genomic and transcriptomic analysis unveils population evolution and development of pesticide resistance in fall armyworm Spodoptera frugiperda

2020 ◽  
Author(s):  
Furong Gui ◽  
Tianming Lan ◽  
Yue Zhao ◽  
Wei Guo ◽  
Yang Dong ◽  
...  

Abstract The fall armyworm (FAW), Spodoptera frugiperda, is a destructive pest native to America and has recently become an invasive insect pest in China. Because of its rapid spread and great risks in China, understanding of FAW genetic background and pesticide resistance is urgent and essential to develop effective management strategies. Here, we assembled a chromosome-level genome of a male FAW (SFynMstLFR) and compared re-sequencing results of the populations from America, Africa, and China. Strain identification of 163 individuals collected from America, Africa and China showed that both C and R strains were found in the American populations, while only C strain was found in the Chinese and African populations. Moreover, population genomics analysis showed that populations from Africa and China have close relationship with significantly genetic differentiation from American populations. Taken together, FAWs invaded into China were most likely originated from Africa. Comparative genomics analysis displayed that the cytochrome p450 gene family is extremely expanded to 425 members in FAW, of which 283 genes are specific to FAW. Treatments of Chinese populations with twenty-three pesticides showed the variant patterns of transcriptome profiles, and several detoxification genes such as AOX, UGT and GST specially responded to the pesticides. These findings will be useful in developing effective strategies for management of FAW in China and other invaded areas.

2019 ◽  
Author(s):  
Lei Zhang ◽  
Bo Liu ◽  
Weigang Zheng ◽  
Conghui Liu ◽  
Dandan Zhang ◽  
...  

AbstractThe rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report a 393.25-M chromosome-level genome assembly of fall armyworm with scaffold N50 of 13.3 M consisting of 23281 annotated protein-coding genes. Genome-wide resequencing of 105 samples from 16 provinces in China revealed that the fall armyworm population comprises a complex inter-strain hybrid, mainly with the corn-strain genetic background and less of the rice-strain genetic background, which highlights the inaccuracy of strain identification using mitochondrial or Tpi genes. An analysis of genes related to pesticide- and Bt-resistance showed that the risk of fall armyworm developing resistance to conventional pesticides is very high, while remaining currently susceptible to Bt toxins. Laboratory bioassay results showed that insects invading China carry resistance to organophosphate and pyrethroid pesticides, but are sensitive to genetically modified maize expressing Cry1Ab in field experiments. Additionally, we found that two mitochondrial fragments are inserted into the nuclear genome, and the insertion event occurred after the differentiation of the two strains. This study represents a valuable advancement toward the analysis of genetic differences among subpopulations and improving management strategies for fall armyworm.


2020 ◽  
Vol 12 (10) ◽  
pp. 16
Author(s):  
Yu Chen ◽  
Jingfei Guo ◽  
Zupeng Gao ◽  
Kanglai He ◽  
Shuxiong Bai ◽  
...  

The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a polyphggous and widespread insect pest. In the study, the biological characteristics and nutritional indices of S. frugiperda fed on six crops, namely corn, sorghum, wheat, soybean, peanut, and cotton, were investigated under laboratory conditions. These crops are cultivated mainly in the mid-high latitude of China. Results showed that S. frugiperda was able to develop and reproduce on all six tested plants. Larvae reared on corn exhibited a significant shorter larval and pupal duration, higher pupal weight, and higher fecundity, which were 16.2 d, 8.9 d, 0.248 g, and 979.4 eggs per female, respectively. The host plant significantly affected relative growth, consumption, and metabolic rates, as well as other nutritional indices. Biology and nutritional indexes suggested that corn was the most suitable host. Besides, peanut, sorghum, and wheat have also been shown to be the suitable hosts for S. frugiperda. Although cotton and soybean were found to be less adequate, high larval and pupal survivors recorded on cotton and soybean leaves have indicated that damage may occur in these plants. This work reveals the damage risk of potential hosts of S. frugiperda, lays the foundation for the design of pest management strategies.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 298
Author(s):  
Ouorou Ganni Mariel Guera ◽  
Federico Castrejón-Ayala ◽  
Norma Robledo ◽  
Alfredo Jiménez-Pérez ◽  
Georgina Sánchez-Rivera ◽  
...  

Chemical control is the main method used to combat fall armyworm in maize crops. However, its indiscriminate use usually leads to a more complex scenario characterized by loss of its effectiveness due to the development of resistance of the insect pest, emergence of secondary pests, and reduction of the populations of natural enemies. For this reason, efforts to develop strategies for agroecological pest management such as Push–Pull are increasingly growing. In this context, the present study was carried out to evaluate field effectiveness of Push–Pull systems for S. frugiperda management in maize crops in Morelos, Mexico. In a randomized block experiment, the incidence and severity of S. frugiperda, the development and yield of maize were evaluated in nine Push–Pull systems and a maize monoculture. The Push–Pull systems presented incidence/severity values lower than those of the monoculture. Morphological development and maize yield in the latter were lower than those of most Push–Pull systems. Mombasa—D. ambrosioides, Mulato II—T. erecta, Mulato II—C. juncea, Tanzania—T. erecta and Tanzania—D. ambrosioides systems presented higher yields than those of monocultures.


Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 615
Author(s):  
Albasini Caniço ◽  
António Mexia ◽  
Luisa Santos

The alien invasive insect pest Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), commonly referred to as fall armyworm (FAW), is causing significant losses to maize production in Africa since its detection in 2016. As an emergency response, governments in several countries distributed and/or promoted massive use of synthetic insecticides among smallholder farmers to fight FAW. The inappropriate use of synthetic insecticides by non-trained and ill-equipped farmers raises environmental and health concerns. This study aimed to assess the occurrence of native parasitoids of FAW, their parasitism rates, and relative abundance in the central province of Manica, Mozambique. A field collection of FAW egg masses and larvae was conducted from May to August 2019 (dry season of the 2018/2019 cropping season) and in December 2019 and January 2020 (rainy season of 2019/2020 cropping season). A total of 101 egg masses and 1444 larvae of FAW were collected from infested fields. Five larval parasitoids were recorded, but no egg parasitism was observed. Coccygidium luteum Brullé (Hymenoptera: Braconidae) and Drino quadrizonula Thomson (Diptera: Tachinidae) were the primary parasitoids. Maximum parasitism of 23.68% and 8.86% and relative abundance of 100 and 96.3 were recorded for C. luteum and D. quadrizonula, respectively. Total parasitism by different parasitoid species was at 9.49%. Cultural practices favoring the action of these parasitoids should be advocated.


1999 ◽  
Vol 28 (4) ◽  
pp. 675-685 ◽  
Author(s):  
Marliton R. Barreto ◽  
Leandro L. Loguercio ◽  
Fernando H. Valicente ◽  
Edilson Paiva

Novel vegetative insecticidal proteins (Vips) identified in the supernatant of Bacillus thuringiensis (B.t.) cultures have shown to provide adequate control over a wide spectrum of economically important crop pests. To evaluate the potential applicability of these proteins against fall armyworm (Spodoptera frugiperda Smith) larvae, the most important insect pest for tropical maize, the characteristics and mortality effects of culture supernatants from five B.t. strains were investigated. Striking differences among strains were detected, not only in terms of efficiency in killing the insect, but also regarding to mortality effects of heated and non-heated supernatants, which were used to distinguish the heat-sensitive protein-derived insecticidal fraction from a thermostable one, with a non-protein nature (b-exotoxinas). The qualitative, quantitative and temporal patterns of total protein secretion in the medium (supernatant) were assessed through spectrophotometry and polyacrylamide gel electrophoresis. The strains showed remarkably distinct rates of growth and timing for protein secretion relative to cell density in culture. Moreover, the electrophoretic-banding patterns also varied in a strain-specific manner, both in denaturing and non denaturing conditions. Polypeptides displaying a molecular weight that is very close to the expected for previously identified Vip3A proteins were found for the strains with high supernatant-mortality ratios. The data suggest the feasibility and usefulness of searching for protein-derived (Vip-like) insecticidal fractions in B.t. supernatants as a mean of developing especific and efficient alternatives of biological control to be employed in integrated pest management programs of S. frugiperda in tropical maize.


2019 ◽  
Vol 86 ◽  
Author(s):  
Marcelo Negrini ◽  
Elisangela Gomes Fidelis ◽  
Daniel Augusto Schurt ◽  
Francisco dos Santos Silva ◽  
Rosely Souza Pereira ◽  
...  

ABSTRACT: Fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) is one of the main pests in maize crop with developing resistance to chemical products and Bt technology. Therefore, alternative control methods such as essential oils are important steps in the implementation management strategies for this pest. This study aimed to evaluate the efficiency of essential oils (EOs) of Corymbia citriodora, Myrciaria dubia (Myrtaceae), Lippia microphylla (Verbenaceae) and Piper umbelattum (Piperaceae) in controlling S. frugiperda. The OEs were extracted and mortality tests were conducted with topic and volatile applications, in 30 second-instar caterpillars originated from insect rearing and artificial diet. As a control, we conducted tests with distilled water and acetone. EOs that provided mortality rates above 80% were submitted to chemical analysis for constituent identification. The efficient EOs were only those of C. citriodora and L. microphylla. For EO of C. citriodora, the LD80 was 7.06 ± 0.73 mg.g-1 in topical application and 5.85 ± 0.75 µL via volatile application. On the other hand, for EO of L. microphylla, DL80 was 9.95 ± 1.25 mg.g-1 in topical application and 18.56 ± 3.55 µL via volatile application. Chemical analysis showed that the main constituents were citronella for the EO of C. citriodora and (E)-caryophyllene and (E)-nerolidol to the EO of L. microphylla. EOs of C. citriodora and L. microphylla are promising for controlling S. frugiperda, with emphasis on the volatile effect of C. citriodora oil.


Author(s):  
P.S. Shanmugam ◽  
M. Sangeetha ◽  
P. Ayyadurai ◽  
Y.G. Prasad

Background: Maize is one of the predominant millets cultivated in an area of 6500 ha both under drip and open irrigation systems in Dharmapuri district. The infestation of invasive insect pest Spodoptera frugiperda poses major threat to maize cultivation and increased the cost towards plant protection since 2018. In the integrated pest management strategies, the benefits of growing border and inter crop has been studied in detail but least emphasis was given to the crops grown in adjacent fields to the main crop. The cropping pattern in Dharmapuri district is highly diversified and the farmers prefer to grow more number of crops across the seasons compared to other maize growing areas. Methods: The present survey envisages the influence of adjacent and border crops on the incidence of fall armyworm in maize. The field incidence of fall armyworm in maize crop surrounded by other crops such as tapioca, nerium, cotton and maize fields with blackgram, cowpea and sesame as border crops were studied during kharif season of 2018 and 2019. Result: The maize fields surrounded by tapioca and nerium crop recorded lower fall armyworm incidence (3.00 - 10.00%) followed by field surrounded by tapioca on either side of maize (4.50 - 14.50%) during 15 to 60 days after emergence. Growing of border crops such as blackgram, sesame and cowpea recorded 24.50, 23.50 and 16.50% incidence at 60 DAE, respectively. With regard to grain yield, no marked variation was observed in different crop combination. The higher return (Rs. 86040/ha) and benefit cost ratio (2.65) was observed in maize crop adjacent to tapioca and nerium crop. The lower net return (Rs. 75360/ha) and benefit cost ratio (2.36) was realized in maize crop adjacent to maize crop. In most of the management strategies pulses have been inducted either border or intercrop to attract natural enemies and thwart the host insects. In the present survey, tapioca and nerium crop combination reduces the fall armyworm incidence. Hence tapioca and nerium crop combinations can be tried as border crop to push the fall armyworm away from the maize crop. The days required for advanced planting and crop combinations should be studied in detail to devise effective fall armyworm management strategies.


Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 777
Author(s):  
Chengfeng Lei ◽  
Jian Yang ◽  
Jia Wang ◽  
Jia Hu ◽  
Xiulian Sun

The fall armyworm, Spodoptera frugiperda, is a new invading pest in China. The baculovirus Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is a pathogenic agent of the fall armyworm and a potential agent for its control in integrated pest management strategies. In this work, we analyze the molecular and biological characteristics of an SfMNPV isolate collected from maize in China (SfMNPV-Hub). Two genotypes were further isolated from SfMNPV-Hub by an in vivo cloning method. The PstI profile of one genotype (SfHub-A) was similar to genotype A of the SfMNPV Colombian isolate, and the other (SfHub-E) was similar to genotype E of the Colombian isolate. The bioactivity of SfHub-A against second-instar S. frugiperda larvae was not significantly different from that of SfMNPV-Hub, whereas SfHub-E was 2.7–5.5 fold less potent than SfMNPV-Hub. The speed of kill of SfHub-E was quicker than SfMNPV-Hub, while SfHub-A acted slower than SfMNPV-Hub. Occlusion body (OB) production of SfHub-A in an S. frugiperda cadaver was significantly higher than that of SfMNPV-Hub, while SfHub-E yielded far fewer occlusion bodies (OBs) in the host larvae. These results provide basic information for developing a virus-based pesticide against the invading pest S. frugiperda.


2017 ◽  
Vol 16 (3) ◽  
pp. 337
Author(s):  
LETÍCIA HELLWIG ◽  
ANDERSON DIONEI GRUTZMACHER ◽  
PATRÍCIA MARQUES DOS SANTOS ◽  
CALISC DE OLIVEIRA TRECHA ◽  
LAUREN BITTENCOURT MEDINA ◽  
...  

 RESUMO - A produção de milho tem sofrido grandes avanços, propiciando aumento de produtividade, no entanto, esta é diretamente afetada pelo ataque de insetos desde o plantio até a sua utilização. Neste contexto, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) é considerada o principal inseto-praga. Para a cultura do milho já existem níveis de controle definidos, entretanto, mesmo utilizando os já estabelecidos, ocorrem perdas na produção. Assim, o objetivo do estudo foi reavaliar o nível de dano de S. frugiperda em milho convencional BG7060, por meio de infestação artificial com diferentes densidades populacionais de lagartas (0, 1, 3, 5, 10, 15 e 20 lagartas planta-1) em plantas no estádio fenológico V4-V8 (folhas completamente expandidas) em condições de casa de vegetação. Os resultados obtidos evidenciaram que o aumento do número de lagartas de S. frugiperda por planta afeta todas as variáveis relacionadas à produtividade, exceto a altura de planta e comprimento da espiga, propiciando uma menor produtividade. Constatou-se que o nível de controle de S. frugiperda para o híbrido BG7060 no estádios V4-V8 é 29% de plantas atacadas em uma amostragem de 100 plantas, quando ocorre uma lagarta planta-1.Palavras-chave: nível de controle, monitoramento, manejo integrado de pragas, Zea mays L. LEVEL OF DAMAGE OF FALL ARMYWORM, Spodoptera frugiperda, IN CONVENTIONAL MAIZE IN GREENHOUSE CONDITIONS  ABSTRACT - The maize production has advanced considerably providing an increase in productivity, however, this is directly affected by the insect attack in all phases. In this context, the fall armyworm Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) is considered the main insect-pest. There is a control levels set for the maize production, however, using the level of control already established, production losses occur. In this sense, the purposes of the study was re-evaluate the level of damage of the S. frugiperda in conventional maize, BG7060, through artificial infestation with different populational densities (0, 1, 3, 5, 10, 15 and 20 caterpillars plant-1), of plants at V4-V8 phenological stage (fully expanded leaves) in green house conditions. The results obtained highlighted that the increase in the number of caterpillars of S. frugiperda by plant affects all variables related to productivity, except the plant height and length of the ear, providing a smaller productivity. It was found that the control level of S. frugiperda for the BG7060 maize for V4-V8 stage is 29% of attacked plants in a sample of 100 plants, when there is one caterpillar per plant.Keywords: level control, monitoring, integrated pest management, Zea mays L.


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