Silicon-based induced resistance in maize against fall armyworm [Spodoptera frugiperda (Lepidoptera: Noctuidae)]

The fall armyworm (Spodoptera frugiperda) is a major economic pest in the United States and has recently become a significant concern in African and Asian countries. Due to its increased resistance to current management strategies, including pesticides and transgenic corn, alternative management techniques have become more necessary. Currently, silicon (Si) is being used in many pest control systems due to its ability to increase plant resistance to biotic and abiotic factors and promote plant growth. The current experiments were carried out at the College of Plant Protection, Gansu Agricultural University, Lanzhou, China, to test the effect of Si on lifetable parameters and lipase activity of fall armyworm and vegetative and physiological parameters of maize plants. Two sources of Si (silicon dioxide: SiO2 and potassium silicate: K2SiO3) were applied on maize plants with two application methods (foliar application and soil drenching). The experiment results revealed that foliar applications of SiO2 and K2SiO3 significantly (P≤0.05) increased mortality percentage and developmental period and decreased larval and pupal biomass of fall armyworm. Similarly, both Si sources significantly (P≤0.05) reduced lipase activity of larvae, and fecundity of adults, whereas prolonged longevity of adults. Among plant parameters, a significant increase in fresh and dry weight of shoot, stem length, chlorophyll content, and antioxidant activity was observed with foliar applications of Si. Root fresh and dry weight was significantly (P ≤ 0.05) higher in plants treated with soil drenching of SiO2 and K2SiO3. Moreover, SiO2 performed better for all parameters as compared to K2SiO3 and control treatment. The study conclusively demonstrated a significant negative effect on various biological parameters of fall armyworm when plants were treated with Si, so it can be a promising strategy to control this pest.

Download Full-text

Virulence and Genetic Characterization of Six Baculovirus Strains Isolated From Different Populations of Spodoptera Frugiperda (Lepidoptera: Noctuidae)

10.21203/rs.3.rs-988050/v1 ◽

2021 ◽

Author(s):

Ingrid Zanella-Saenz ◽

Elisabeth A. Herniou ◽

Jorge E. Ibarra ◽

Ma.Cristina Del Rincón-Castro ◽

Ilse Alejandra Huerta-Arredondo

Keyword(s):

Biological Control ◽

Cell Cultures ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

The United States ◽

Infection Mechanisms ◽

Different Populations

Abstract Fall armyworm (FAW), Spodoptera frugiperda (Smith, 1797), is a polyphagous, voracious, and economically important agricultural pest. Biological control of FAW is a strategy that must be further explored. This study evaluated six baculovirus strains isolated from infected FAW larvae from Mexico, Argentina, Honduras, and the United States. Five alphabaculoviruses (SfNPV-An2, SfNPV-Arg, SfNPV-Fx, SfNPV-Ho and SfNPV-Sin) and one betabaculovirus (SfGV-RV), were tested against FAW larvae, showing a wide diversity of virulence levels among strains when their estimated LC50s were compared, being SfNPVArg, SfNPV-Ho and SfNPV-Fx more virulent than SfNPV-An 2 , SfNPV-Sin and SfGV-RV. To determine any virulence difference in vitro studies of these isolates, Sf9 cell cultures were used. Interestingly, only ODVs from four of the test SfNPV strains showed infectivity on Sf9 cell cultures, and some differences in virulence were observed. Genomic restriction analyses and partial sequences of lef-8, lef-9 , and polh/granulin genes showed little variability among alphabaculoviruses, both, among them and with previously reported sequences. However, sequences from SfGV-RV were closer to previously reported sequences from the SfGVVG008 strain than the SfGV-Arg and SfGV-VG014 strains. The great difference in the in vivo virulence was not correlated with great similarity among the isolates. The characterization of these six baculoviruses isolates offers the basis for exploring their potential as biological control agents against S. frugiperda, as well the initial studies on their specific infection mechanisms, evolution, and ecology.

Download Full-text

Examination of Acephate Absorption, Transport, Metabolism, and Accumulation in Maize After Root Irrigation for Spodoptera Frugiperda Control

10.21203/rs.3.rs-407085/v1 ◽

2021 ◽

Author(s):

jiyingzi Wu ◽

xianjia Li ◽

ruiquan Hou ◽

kunyu Zhao ◽

yongqin Wang ◽

...

Keyword(s):

Pest Control ◽

Spodoptera Frugiperda ◽

Control Method ◽

Control Measure ◽

Fall Armyworm ◽

Extended Period ◽

Field Trials ◽

Pesticide Use ◽

Control Efficacy ◽

Maize Plants

Abstract BACKGROUND: Since the invasion of the fall armyworm moth (Spodoptera frugiperda) in China in January 2019, damage to maize crops has gradually intensified, and chemical control has become the main control measure. This study aimed to examine methods of effective pest control while monitoring the environmental impact of pesticide use. The effectiveness of S. frugiperda pest control by foliar spraying and root irrigation of maize plants with acephate was determined, and the absorption, distribution, and dissipation of acephate and methamidophos by maize were studied.RESULTS: Field trials showed that acephate treatment at 6000 g.a.i ha-1 was the most effective for controlling S. frugiperda. Acephate and methamidophos were absorbed from the roots, transported upward, and concentrated in the leaves, particularly new leaves. The terminal residues of acephate and methamidophos in maize grains were below detectable levels at 60 days after treatment.CONCLUSIONS: The results demonstrate that acephate treatment via root irrigation can more effectively control the infestation of S. frugiperda in maize than acephate treatment via foliar spraying. The translocation and distribution of acephate and methamidophos by root irrigation were more uniform, and the holding efficiency was higher than those in foliar spraying, suggesting an extended period of control efficacy. This pest control method could be utilized to reduce pesticide residues while safely and efficiently controlling S. frugiperda infestation.

Download Full-text

Aqueous Garlic Extract as a Plant Biostimulant Enhances Physiology, Improves Crop Quality and Metabolite Abundance, and Primes the Defense Responses of Receiver Plants

Applied Sciences ◽

10.3390/app8091505 ◽

2018 ◽

Vol 8 (9) ◽

pp. 1505 ◽

Cited By ~ 8

Author(s):

Sikandar Hayat ◽

Husain Ahmad ◽

Muhammad Ali ◽

Kashif Hayat ◽

Muhammad Khan ◽

...

Keyword(s):

Foliar Application ◽

Fungal Infections ◽

Soluble Sugars ◽

Dry Weight ◽

Defense Responses ◽

Garlic Extract ◽

Control Treatment ◽

Antioxidant Systems ◽

Plant Metabolites ◽

Crop Quality

Biostimulants are the next-generation choice for sustainable agricultural production and are gradually becoming an alternative to synthetic chemicals. Various botanicals are proposed to exert stimulatory effects, and garlic allelochemicals are among such botanicals; however, a peer-reviewed scientific evaluation is required to understand garlic-derived substances such as biostimulants. Current studies were therefore performed to identify the bioactivity of garlic extract as a biostimulant to improve crop quality, alter its physiological potential, and prime its defense responses against pathogenic fungal infections. 100 µg mL−1 aqueous garlic extracts (AGE) in consort with 1 mM of acetyl salicylic acid (ASA) and distilled water as a control treatment were applied to eggplant and pepper seedlings as foliar application and fertigation methods. The results revealed stimulatory responses in the growth of the vegetables with improved plant height, number of leaves, root growth, fresh and dry weight, etc., due to AGE and ASA applications. Moreover, significant alterations were indicated in plant metabolites such as chlorophyll, carotenoids, and soluble sugars. Additionally, stimulation of the antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD), as well as the root activity of these plants, was observed after treatment. Application of AGE and ASA also exerted priming effects on pepper plants, inducing defense responses prior to Phytopthora capsici inoculation, and the treated plants therefore successfully resisted infection through activated antioxidant systems, and probably carotenoid and other protectory metabolites. Stress-induced H2O2 content was extremely low in the treated plants, indicating successful resistance against pathogenic infection.

Download Full-text

Effect of seed treatment with insecticides on the control of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in soybean

Arquivos do Instituto Biológico ◽

10.1590/1808-1657000332018 ◽

2019 ◽

Vol 86 ◽

Cited By ~ 1

Author(s):

Yago Barros Triboni ◽

Luciano Del Bem Junior ◽

Carlos Gilberto Raetano ◽

Matheus Mereb Negrisoli

Keyword(s):

Spodoptera Frugiperda ◽

Seed Treatment ◽

Yield Loss ◽

Insect Pests ◽

Fall Armyworm ◽

Control Treatment ◽

Control Efficacy ◽

Thiophanate Methyl ◽

Crop Development ◽

Lepidoptera Noctuidae

ABSTRACT Fall armyworm is one of the main insect pests in Brazil. Thus, the present work aimed to evaluate the seed treatment effect on the control of Spodoptera frugiperda in initial infestations of soybean crops. The experimental design was completely randomized with four replicates of six insecticide treatments applied through seed treatment: imidacloprid plus thiodicarb at the dose of 52.5 plus 105 g a.i. (active ingredient) 100 kg-1 of seed (Cropstar® 0.350 L 100 kg-1 of seed); thiamethoxam at 105 g a.i. 100 kg-1 of seed (Cruiser 350 FS® 0.3 L 100 kg-1 of seed); chlorantraniliprole at 62.5 g a.i. 100 kg-1 of seed (Dermacor® 0.1 L 100 kg-1 of seed); cyantraniliprole at 120 g a.i. 100 kg-1 of seed (Fortenza 600 FS® 0.2 L 100 kg-1 of seed); fipronil plus pyraclostrobin and thiophanate-methyl 50 + 5 + 45 g a.i. 100 kg-1 of seed (Standak Top® 0.2 L 100 kg-1 of seed), and a control treatment. The experiment was carried out in a greenhouse. Diamide insecticides (chlorantraniliprole and cyantraniliprole) presented the best results among all treatments, with lower consumption of the treated leaves by the caterpillars and greater control efficacy of this insect. We verified that seed treatment is a viable alternative for controlling S. frugiperda at the beginning of crop development, when the caterpillar presents the behavior of cutting the seedlings and/or the consumption of leaf area, causing a reduction in the plant population and a consequent yield loss.

Download Full-text

Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

10.1101/2020.09.25.314005 ◽

2020 ◽

Author(s):

Katrina A. Schlum ◽

Kurt Lamour ◽

Caroline Placidi de Bortoli ◽

Rahul Banerjee ◽

Scott J. Emrich ◽

...

Keyword(s):

United States ◽

Puerto Rico ◽

Gene Flow ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

The United States ◽

Genomic Diversity ◽

Whole Genome ◽

Long Distance ◽

Host Strains

AbstractThe fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of >80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and the United States (USA) were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest panmixia in this population, other than a minor reduction in gene flow between the two overwintering populations in the continental USA that also corresponded to genetically distinct host strains. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Comparisons between laboratory-reared and field collected S. frugiperda support similar genomic diversity, validating the experimental use of laboratory strains. Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations.

Download Full-text

Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

BMC Genomics ◽

10.1186/s12864-021-07492-7 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Katrina A. Schlum ◽

Kurt Lamour ◽

Caroline Placidi de Bortoli ◽

Rahul Banerjee ◽

Robert Meagher ◽

...

Keyword(s):

United States ◽

Puerto Rico ◽

Gene Flow ◽

Spodoptera Frugiperda ◽

Fall Armyworm ◽

The United States ◽

Whole Genome ◽

Long Distance ◽

Field Samples ◽

Host Strains

Abstract Background The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of > 80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). The population genomics of the United States (USA) fall armyworm remains poorly characterized to date despite its agricultural threat. Results In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and USA were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest a panmictic S. frugiperda population, with only a minor reduction in gene flow between the two overwintering populations in the continental USA, also corresponding to distinct host strains at the mitochondrial level. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Conclusions Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations. Based on the genomic similarities found between host strains and laboratory vs. field samples, our findings validate the experimental use of laboratory strains and the host strain differentiation based on mitochondria and sex-linked genetic markers extends to minor genome wide differences with some exceptions showing mixture between host strains is likely occurring in field populations.

Download Full-text

Maize Infestation of Fall Armyworm (Lepidoptera: Noctuidae) Within Agro-Ecological Zones of Togo and Ghana in West Africa 3 Yr After Its Invasion

Environmental Entomology ◽

10.1093/ee/nvaa048 ◽

2020 ◽

Vol 49 (3) ◽

pp. 645-650 ◽

Cited By ~ 2

Author(s):

Djima Koffi ◽

Komi Agboka ◽

Delanyo Kokouvi Adenka ◽

Michael Osae ◽

Agbeko Kodjo Tounou ◽

...

Keyword(s):

Spodoptera Frugiperda ◽

Fall Armyworm ◽

West African ◽

Economic Damage ◽

African Countries ◽

Ecological Zones ◽

Management Interventions ◽

Maize Plants ◽

Lepidoptera Noctuidae ◽

Agro Ecological Zones

Abstract The fall armyworm Spodoptera frugiperda (J. E. Smith) invaded several West African countries in 2016 causing severe injury to maize plants and economic damage. This study assesses variations in the occurrence of this species in different Agro-Ecological Zones (AEZs) in Togo and Ghana during the 3 yr following its discovery. The surveys were conducted on 120 farms in Togo and 94 farms in Ghana by collecting larvae from 200 maize plants per hectare. Infestation levels were 68.46% in 2016, 55.82% in 2017, and 17.76% in 2018. The number of larvae recorded per hectare and infestation levels were higher in Togo than in Ghana. The lowest number of collected larvae and infestation levels of S. frugiperda were in 2018, compared to the other 2 yr. Larvae per hectare and the infestation level varied regionally inside the two countries. The southern part of Togo (AEZ five) contained higher numbers of larvae and higher infestation levels during the 2 yr following the invasion of the pest. We concluded that infestation levels of S. frugiperda are much lower in 2018 than the two previous years and it is therefore necessary to determine the factors that affect the population dynamics of S. frugiperda in the field, which is a perquisite for developing management interventions.

Download Full-text

Rapid identification of the invasive fall armyworm Spodoptera frugiperda (Lepidoptera, Noctuidae) using species-specific primers in multiplex PCR

Scientific Reports ◽

10.1038/s41598-020-73786-7 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Cheng-Lung Tsai ◽

I.-Hsuan Chu ◽

Ming-Hsun Chou ◽

Theeraphap Chareonviriyaphap ◽

Ming-Yao Chiang ◽

...

Keyword(s):

Spodoptera Frugiperda ◽

Egg Production ◽

Mainland China ◽

Fall Armyworm ◽

The United States ◽

Rapid Identification ◽

Economic Losses ◽

Specific Primers ◽

Wide Range ◽

Species Specific

Abstract The fall armyworm (FAW), Spodoptera frugiperda (Smith), is a major pest native to the Americas. A recent invasion of FAWs from Africa eastward to South Asia, the Indochina Peninsula, and mainland China has received much attention due to the considerable economic losses in agriculture. FAWs can rapidly colonise a new area, likely due to the wide range of host plants, good flying capability, and high egg production. Therefore, a convenient, quick, and accurate tool for FAW identification is urgently required to establish a FAW invasion management strategy. In this study, FAW-specific primers were designed to recognise FAWs on the basis of internal transcribed spacer 1 (ITS1). The results revealed the accurate FAW recognition of the three congeneric species and eight common corn lepidopteran pests, especially at their larval stage. Furthermore, species-specific primers have confirmed their efficacy by using 69 FAW specimens from Taiwan, Thailand, and the United States, with a 96% success rate, excluding 3 decayed specimens. By using the simple, reliable, and convenient FAW-specific primers, a pest management programme can be developed not only to reduce sequencing costs and experimental time from 2 days to 4 h, but eradicate the FAW as soon as it enters a new area.

Download Full-text

Dispersal and Seasonal Occurrence of Noctuidonema guyanense, an Ectoparasitic Nematode of Adult Fall Armyworm (Lepidoptera: Noctuidae), in the United States2

Journal of Entomological Science ◽

10.18474/0749-8004-26.1.136 ◽

1991 ◽

Vol 26 (1) ◽

pp. 136-148 ◽

Cited By ~ 11

Author(s):

Alvin M. Simmons ◽

Charlie E. Rogers

Keyword(s):

Spodoptera Frugiperda ◽

Gulf Coast ◽

Fall Armyworm ◽

The United States ◽

Adult Males ◽

West Texas ◽

Percent Parasitism ◽

Important Regulator ◽

Lepidoptera Noctuidae ◽

Eastern Half

Migrant Spodoptera frugiperda (J. E. Smith) adult males were collected at 17 widely separated locations throughout the eastern half of the United States and were examined to determine if Noctuidonema guyanense Remillet and Silvain, an ectoparasitic nematode of adult Lepidoptera, were transported with the host. Nematodes were recovered from all locations where moths were captured. Nematode populations and parasitism of fall armyworm males were higher in the eastern states than in the Plains, Midwestern, and Central states (e.g., west Texas, Iowa, and Ohio). Percent parasitism and the number of nematodes per infested fall armyworm changed over time at each location. The initial immigrant fall armyworm males at a given location generally had few or no nematodes. These data suggest that moths with a moderate number of nematodes may be less able to disperse. Nematode populations peaked in mid-to-late August and then declined to a few or none by mid-October at locations north of the Gulf Coast area. Among other factors, temperature is apparently an important regulator of N. guyanense populations.

Download Full-text

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.

Download Full-text