Baseline Susceptibility of Spodoptera frugiperda Populations Collected in India towards Different Chemical Classes of Insecticides

Fall armyworm (FAW), Spodoptera frugiperda, is a major pest of maize in the Americas and recently invaded the Eastern hemisphere. It was first detected in India in 2018 and is considered a major threat to maize production. FAW control largely relies on the application of chemical insecticides and transgenic crops expressing Bacillus thuringiensis insecticidal proteins. Assessing FAW resistance and insecticide susceptibility is a cornerstone to develop sustainable resistance management strategies. In this study, we conducted more than 400 bioassays to assess the efficacy of nine insecticides from seven mode-of-action classes against 47 FAW populations collected in 2019 and 2020 across various geographical areas in India. The resistance status of the field-collected populations was compared to an Indian population sampled in 2018, and an insecticide susceptible reference population collected in 2005 in Brazil. Low to moderate resistance levels were observed for thiodicarb, chlorpyriphos, deltamethrin, chlorantraniliprole and flubendiamide in several populations (including the reference population collected in 2018). The highest resistance ratios were observed for deltamethrin which likely compromises recommended label rates for pyrethroid insecticides in general. Our data provide a useful baseline for future FAW resistance monitoring initiatives and highlight the need to implement insecticide resistance management strategies.

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Monitoring of Target-Site Mutations Conferring Insecticide Resistance in Spodoptera frugiperda

Insects ◽

10.3390/insects11080545 ◽

2020 ◽

Vol 11 (8) ◽

pp. 545 ◽

Cited By ~ 1

Author(s):

Debora Boaventura ◽

Macarena Martin ◽

Alberto Pozzebon ◽

David Mota-Sanchez ◽

Ralf Nauen

Keyword(s):

Insecticide Resistance ◽

Spodoptera Frugiperda ◽

Resistance Management ◽

Fall Armyworm ◽

Target Site ◽

Diagnostic Methods ◽

Allelic Discrimination ◽

Tropical Regions ◽

Voltage Gated Sodium Channels ◽

Major Pest

Fall armyworm (FAW), Spodoptera frugiperda, a major pest of corn and native to the Americas, recently invaded (sub)tropical regions worldwide. The intensive use of insecticides and the high adoption of crops expressing Bacillus thuringiensis (Bt) proteins has led to many cases of resistance. Target-site mutations are among the main mechanisms of resistance and monitoring their frequency is of great value for insecticide resistance management. Pyrosequencing and PCR-based allelic discrimination assays were developed and used to genotype target-site resistance alleles in 34 FAW populations from different continents. The diagnostic methods revealed a high frequency of mutations in acetylcholinesterase, conferring resistance to organophosphates and carbamates. In voltage-gated sodium channels targeted by pyrethroids, only one population from Indonesia showed a mutation. No mutations were detected in the ryanodine receptor, suggesting susceptibility to diamides. Indels in the ATP-binding cassette transporter C2 associated with Bt-resistance were observed in samples collected in Puerto Rico and Brazil. Additionally, we analyzed all samples for the presence of markers associated with two sympatric FAW host plant strains. The molecular methods established show robust results in FAW samples collected across a broad geographical range and can be used to support decisions for sustainable FAW control and applied resistance management.

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Spread and impact of fall armyworm (Spodoptera frugiperda J.E. Smith) in maize production areas of Kenya

Agriculture Ecosystems & Environment ◽

10.1016/j.agee.2019.106804 ◽

2020 ◽

Vol 292 ◽

pp. 106804 ◽

Cited By ~ 6

Author(s):

Hugo De Groote ◽

Simon C. Kimenju ◽

Bernard Munyua ◽

Sebastian Palmas ◽

Menale Kassie ◽

...

Keyword(s):

Spodoptera Frugiperda ◽

Fall Armyworm ◽

Maize Production ◽

Production Areas

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Insecticidal activity of essential oils in controlling fall armyworm, Spodoptera frugiperda

Arquivos do Instituto Biológico ◽

10.1590/1808-1657001112018 ◽

2019 ◽

Vol 86 ◽

Author(s):

Marcelo Negrini ◽

Elisangela Gomes Fidelis ◽

Daniel Augusto Schurt ◽

Francisco dos Santos Silva ◽

Rosely Souza Pereira ◽

...

Keyword(s):

Chemical Analysis ◽

Essential Oils ◽

Topical Application ◽

Spodoptera Frugiperda ◽

Management Strategies ◽

Fall Armyworm ◽

Maize Crop ◽

Insect Rearing ◽

Corymbia Citriodora ◽

Implementation Management

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.

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Influence of Adjacent and Border Crops on the Incidence of Fall Armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in Maize

Indian Journal of Agricultural Research ◽

10.18805/ijare.a-5676 ◽

2021 ◽

Author(s):

P.S. Shanmugam ◽

M. Sangeetha ◽

P. Ayyadurai ◽

Y.G. Prasad

Keyword(s):

Spodoptera Frugiperda ◽

Plant Protection ◽

Management Strategies ◽

Fall Armyworm ◽

Cost Ratio ◽

Cropping Pattern ◽

Present Survey ◽

Maize Crop ◽

Benefit Cost Ratio ◽

Benefit Cost

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.

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Fall Armyworm, Spodoptera frugiperda Infestations in East Africa: Assessment of Damage and Parasitism

Insects ◽

10.3390/insects10070195 ◽

2019 ◽

Vol 10 (7) ◽

pp. 195 ◽

Cited By ~ 14

Author(s):

Birhanu Sisay ◽

Josephine Simiyu ◽

Esayas Mendesil ◽

Paddy Likhayo ◽

Gashawbeza Ayalew ◽

...

Keyword(s):

Biological Control ◽

East Africa ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

Egg Parasitoid ◽

Leaf Damage ◽

Parasitism Rate ◽

Maize Production ◽

Larval Parasitoid ◽

Percent Parasitism

The fall armyworm (FAW), Spodoptera frugiperda, threatens maize production in Africa. A survey was conducted to determine the distribution of FAW and its natural enemies and damage severity in Ethiopia, Kenya and Tanzania in 2017 and 2018. A total of 287 smallholder maize farms (holding smaller than 2 hectares of land) were randomly selected and surveyed. FAW is widely distributed in the three countries and the percent of infested maize fields ranged from 33% to 100% in Ethiopia, 93% to 100% in Tanzania and 100% in Kenya in 2017, whereas they ranged from 80% to 100% and 82.2% to 100% in Ethiopia and Kenya, respectively, in 2018. The percent of FAW infestation of plants in the surveyed fields ranged from 5% to 100%. In 2017, the leaf damage score of the average of the fields ranged from 1.8 to 7 (9 = highest level of damage), while 2018, it ranged from 1.9 to 6.8. In 2017, five different species of parasitoids were recovered from FAW eggs and larvae. Cotesia icipe (Hymenoptera: Braconidae) was the main parasitoid recorded in Ethiopia, with a percent parasitism rate of 37.6%. Chelonus curvimaculatus Cameron (Hymenoptera: Braconidae) was the only egg-larval parasitoid recorded in Kenya and had a 4.8% parasitism rate. In 2018, six species of egg and larval parasitoids were recovered with C. icipe being the dominant larval parasitoid, with percentage parasitism ranging from 16% to 42% in the three surveyed countries. In Kenya, Telenomus remus (Hymenoptera: Scelionidae) was the dominant egg parasitoid, causing up to 69.3% egg parasitism as compared to only 4% by C. curvimaculatus. Although FAW has rapidly spread throughout these three countries, we were encouraged to see a reasonable level of biological control in place. Augmentative biological control can be implemented to suppress FAW in East Africa.

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Molecular and Biological Characterization of Spodoptera frugiperda Multiple Nucleopolyhedrovirus Field Isolate and Genotypes from China

Insects ◽

10.3390/insects11110777 ◽

2020 ◽

Vol 11 (11) ◽

pp. 777

Author(s):

Chengfeng Lei ◽

Jian Yang ◽

Jia Wang ◽

Jia Hu ◽

Xiulian Sun

Keyword(s):

Spodoptera Frugiperda ◽

Field Isolate ◽

Management Strategies ◽

Fall Armyworm ◽

Multiple Nucleopolyhedrovirus ◽

Cloning Method ◽

Occlusion Bodies ◽

Colombian Isolate

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.

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Modelling the Control of the Impact of Fall Armyworm (Spodoptera frugiperda) Infestations on Maize Production

International Journal of Differential Equations ◽

10.1155/2021/8838089 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Salamida Daudi ◽

Livingstone Luboobi ◽

Moatlhodi Kgosimore ◽

Dmitry Kuznetsov

Keyword(s):

Spodoptera Frugiperda ◽

Egg Production ◽

Bounded Solution ◽

Fall Armyworm ◽

Subsequent Increase ◽

Maize Production ◽

Severe Effect ◽

Exogenous Factors ◽

Maize Plants ◽

The Impact

In this paper, we propose and analyze a stage-structured mathematical model for modelling the control of the impact of Fall Armyworm infestations on maize production. Preliminary analysis of the model in the vegetative and reproductive stages revealed that the two systems had a unique and positively bounded solution for all time t ≥ 0 . Numerical analysis of the model in both stages under two different cases was also considered: Case 1: different number of the adult moths in the field assumed at t = 0 and Case 2: the existence of exogenous factors that lead to the immigration of adult moths in the field at time t > 0 . The results indicate that the destruction of maize biomass which is accompanied by a decrease in maize plants to an average of 160 and 142 in the vegetative and reproductive stages, respectively, was observed to be higher in Case 2 than in Case 1 due to subsequent increase in egg production and density of the caterpillars in first few (10) days after immigration. This severe effect on maize plants caused by the unprecedented number of the pests influenced the extension of the model in both stages to include controls such as pesticides and harvesting. The results further show that the pest was significantly suppressed, resulting in an increase in maize plants to an average of 467 and 443 in vegetative and reproductive stages, respectively.

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High-depth resequencing reveals hybrid population and insecticide resistance characteristics of fall armyworm (Spodoptera frugiperda) invading China

10.1101/813154 ◽

2019 ◽

Cited By ~ 7

Author(s):

Lei Zhang ◽

Bo Liu ◽

Weigang Zheng ◽

Conghui Liu ◽

Dandan Zhang ◽

...

Keyword(s):

Spodoptera Frugiperda ◽

Genetic Background ◽

Field Experiments ◽

Management Strategies ◽

Nuclear Genome ◽

Fall Armyworm ◽

Hybrid Population ◽

Strain Identification ◽

Protein Coding ◽

Pyrethroid Pesticides

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.

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Evidence that a major subpopulation of fall armyworm found in the Western Hemisphere is rare or absent in Africa, which may limit the range of crops at risk of infestation

10.1101/482935 ◽

2018 ◽

Author(s):

Rodney N. Nagoshi

Keyword(s):

High Risk ◽

Genetic Markers ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

Western Hemisphere ◽

Mitochondrial Markers ◽

Major Threat ◽

Eastern Hemisphere ◽

Plant Hosts ◽

Risk Of Fall

AbstractThe introduction and establishment of fall armyworm (Spodoptera frugiperda) in Africa presents a major threat to agriculture in that continent and potentially to the entire Eastern Hemisphere. The species is subdivided into two subpopulations called the R-strain and C-strain that differ in their distribution on different plant hosts. This means that the scope of the economic risk posed by invasive fall armyworm is influenced by whether one or both strains are present. Multiple studies have found mitochondrial markers diagnostic of the two strains throughout Africa but there is substantial disagreement with a nuclear strain marker that makes conclusions about strain composition uncertain. In this study the issue of whether both strains are present in Africa was tested by an assay that can detect strain-biased mating behaviors. Western Hemisphere fall armyworm consistently showed evidence of strain-specific assortative mating in the field that was not found in surveys from multiple locations in Africa. The absence of strain mating biases and the disagreements between the strain diagnostic genetic markers indicates that the R-strain is rare (<1% of the population) or absent in Africa. Instead, it appears that the African fall armyworm populations are dominated by two groups, the C-strain and the descendants of interstrain hybrids. These results suggest that plant hosts associated with the R-strain may not be at high risk of fall armyworm infestation in Africa.

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Performance of Spodoptera frugiperda (Lepidoptera: Noctuidae) Fed on Six Host Plants: Potential Risks to Mid-high Latitude Crops in China

Journal of Agricultural Science ◽

10.5539/jas.v12n10p16 ◽

2020 ◽

Vol 12 (10) ◽

pp. 16

Author(s):

Yu Chen ◽

Jingfei Guo ◽

Zupeng Gao ◽

Kanglai He ◽

Shuxiong Bai ◽

...

Keyword(s):

Spodoptera Frugiperda ◽

High Latitude ◽

Insect Pest ◽

Management Strategies ◽

Fall Armyworm ◽

Pupal Weight ◽

Nutritional Indices ◽

Affected Relative ◽

Soybean Leaves ◽

Lepidoptera Noctuidae

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.

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