Unravelling the efficacy and reproductive potential of newly discovered entomopathogenic nematodes, Steinernema indicum and Steinernema shori against Spodoptera frugiperda in maize
Aug 2026· Frontiers in Plant Science· Vol 17· 0 citations· 40 references
Medicine
TL;DR
The present study highlights the potential of S. shori as a biological control agent against the larval and pupal stages of S. frugiperda and evaluates its efficacy against other economically important insect pests and under diverse environmental conditions to support its wider field application.
Abstract
Introduction Spodoptera frugiperda (J.E. Smith), commonly known as the fall armyworm, is one of the most destructive insect pests of maize worldwide, causing substantial economic losses. Its widespread occurrence and increasing resistance to conventional insecticides have intensified the need for effective and sustainable management approaches. Reliance on chemical pesticides not only accelerates resistance development but also poses significant risks to the environment and beneficial non-target organisms. Consequently, environmentally friendly alternatives, particularly biological control strategies, are gaining importance as viable components of integrated pest management programs for this pest. Methods In the present study, the susceptibility of the larval and pupal stages of S. frugiperda to two indigenous entomopathogenic nematode (EPN) species, Steinernema shori NBAIRS80 and Steinernema indicum NBAIRS58, was assessed. The effect of different concentrations of infective juveniles (IJs) of S. indicum and S. shori on their reproductive potential in third-instar S. frugiperda larvae was also investigated under laboratory conditions. Furthermore, the efficacy of S. indicum and S. shori against S. frugiperda was evaluated under both pot and field conditions. Results Results revealed that under laboratory conditions, both EPN species exhibited high virulence against third, fourth, and sixth instar larvae, achieving 100.0% mortality as the concentration increased from 20 to 420 IJs larva-1. However, S. shori caused significantly higher mortality than S. indicum. A similar trend was recorded in pupae, where S. shori caused 81.0% mortality compared to 65.0% by S. indicum. Both species were able to penetrate the larvae and complete their life cycles, producing a higher number of infective juveniles (IJs). However, in both species, penetration declined significantly at higher IJ concentrations. Although emamectin benzoate performed better than both EPN species under both pot and field conditions, S. shori showed improved performance in reducing larval populations after the second round of spraying. Conclusion Considering its effectiveness and environmental safety, the present study highlights the potential of S. shori as a biological control agent against the larval and pupal stages of S. frugiperda. Future studies should evaluate its efficacy against other economically important insect pests and assess its performance under diverse environmental conditions to support its wider field application.
The maize weevil (Sitophilus zeamais Motschulsky, 1885) and the red flour beetle (Tribolium castaneum Herbst, 1797) are among the most economically significant coleopteran pests affecting stored products worldwide. Their infestations result in substantial quantitative and qualitative losses due to grain damage by both larvae and adults. Conventional control strategies rely heavily on chemical insecticides, which pose risks of environmental contamination and contribute to the development of resistant pest populations. As a sustainable alternative, entomopathogenic nematodes (EPN) offer potential for the biological control of insects in cryptic habitats. This study aimed to evaluate the pathogenicity and virulence of eight Brazilian EPN isolates, six from the genus Heterorhabditis and two from Steinernema, against adults of S. zeamais and T. castaneum under laboratory conditions. In addition, S. carpocapsae and H. bacteriophora were included as positive controls. All EPN demonstrated pathogenicity against both pest species, with Steinernema carpocapsae, Steinernema sp. CER21, S. brazilense, and Heterorhabditis amazonensis MC01 showing mortality rates above 25% at a concentration of 1,000 infective juveniles (IJ)mL−1. Subsequent virulence assays revealed that S. carpocapsae and S. brazilense caused the highest mortality in S. zeamais, reaching 86.7% and 76.4%, respectively, at 5,000 IJ.mL−1. For T. castaneum, S. brazilense, and S. carpocapsae caused mortality rates of 69.1% and 56.7%, respectively, at the same concentration. Lethal concentration estimates indicated that S. carpocapsae exhibited slightly higher efficiency against S. zeamais (LC90 = 4,699 IJ.mL−1) compared to S. brazilense (LC90 = 5,497 IJ.mL−1), with values in proximity. Similarly, for T. castaneum, both nematodes showed comparable virulence, with LC90 values of 7,482 IJ.mL−1 for S. carpocapsae and 6,480 IJ.mL−1 for S. brazilense. These findings demonstrate the high potential of S. brazilense as biological control agent against key pests of stored grains.
Ezequiel Garcia-Souza, Mariana Macedo de Souza, Thamiris Gabrielle Bibiano et al.· Journal of plant diseases an...· 0 citations
Overall, several fungal species successfully colonized plant tissues and reduced FAW performance through increased larval mortality, delayed development, and reduced feeding, and effects were associated with the production of bioactive secondary metabolites, induction of plant defense responses, and alteration of volatile organic compound emissions.
Nongamanégré Kouanda, Ibtissem Ben Fekih, M. Cokola et al.· Plants· 0 citations
Spodoptera frugiperda (J.E. Smith) is a destructive invasive pest that poses a serious threat to maize production, necessitating the development of sustainable management strategies. The present study evaluated the efficacy of integrating selective insecticides with Metarhizium anisopliae for the management of fall armyworm under field conditions. Field experiments were conducted at two locations in South Gujarat, India, during the Rabi 2025–26 season using novaluron 5.25 + emamectin benzoate 0.9 SC and thiamethoxam 12.60 + lambda-cyhalothrin 9.50 SC applied alone and in combination with M. anisopliae, along with M. anisopliae alone and an untreated control. Repeated-measures mixed-effects analysis revealed significant treatment effects on plant infestation, leaf damage, cob infestation and cob yield. Among the evaluated treatments, novaluron 5.25 + emamectin benzoate 0.9 SC integrated with M. anisopliae recorded the lowest plant infestation (32.92%), leaf damage score (2.70) and cob infestation (11.01%), and produced the highest cob yield (13.21 t ha⁻¹), representing a 40.53% increase over the untreated control. Although statistically comparable with novaluron 5.25 + emamectin benzoate 0.9 SC applied alone for most parameters, the integrated treatment consistently showed numerically superior performance. In contrast, M. anisopliae applied alone provided only moderate suppression of fall armyworm and lower yield protection than insecticide-based treatments. These findings demonstrate that integrating M. anisopliae with selective insecticides improves fall armyworm management and maize productivity, highlighting its potential as an effective component of integrated pest management (IPM) for sustainable maize production.
Nisarg Panchal, M. Siddhapara, V. M. Khimani et al.· Uttar Pradesh Journal of Zoo...· 0 citations
Findings indicate that compatible combinations of M. anisopliae with selective insecticides demonstrated strong potential for the environmentally sound management of P. xylostella as part of an integrated pest management programme.
Shaik Sushma Shareen, Vibha Pandey, Abhishek Shukla et al.· Journal of Experimental Agri...· 0 citations
The fall armyworm, Spodoptera frugiperda (Smith, 1797), is a major agricultural pest worldwide because of its polyphagous feeding habits, broad geographic distribution, and high adaptive capacity. Although maize is its primary host, the species can attack more than 350 plant species across 76 botanical families, causing substantial yield losses in several cropping systems. This study evaluated the efficacy of chemical and biological insecticides against S. frugiperda by assessing larval mortality, median lethal time (LT₅₀), and the time required to achieve 90% mortality (LT₉₀) in second- and third-instar larvae. The experiment was conducted at the Integrated Pest Management Laboratory of the Federal University of Santa Maria (LabMIP–UFSM), Brazil, between May and June 2023, using a completely randomized design with five insecticide treatments (Cartugen®, Dipel®, Exalt®, Prêmio®, and Lannate®), an untreated control, and ten replicates. All evaluated insecticides significantly increased larval mortality compared with the untreated control. Lannate® exhibited the highest efficacy, reaching 50%, 90%, and 100% mortality of second-instar larvae approximately 15, 23, and 30 h after application, respectively, whereas the same mortality levels in third-instar larvae were achieved after approximately 23, 40, and 42 h. Biological insecticides also provided effective control; however, their insecticidal activity was slower than that of the chemical insecticides. Overall, chemical insecticides showed superior performance in both larval stages, with Lannate® standing out as the most effective treatment. These findings provide robust experimental evidence to support insecticide selection and contribute to more effective and sustainable integrated pest management programs for S. frugiperda.
Joaquim Almério Jerónimo, W. Boller, D. A. Magano et al.· Brazilian Journal of Animal...· 0 citations
Fall armyworm (Spodoptera frugiperda) is one of the most destructive invasive pests affecting maize and other cereal crops worldwide. Since its introduction into Africa in 2016, the pest has spread rapidly across Sub-Saharan Africa and several Asian countries, causing significant yield losses and threatening food security. This review evaluated the occurrence and biocontrol potential of natural enemies of fall armyworm through a systematic assessment of published literature obtained from scientific journals, institutional reports, textbooks, conference proceedings, and online databases. Information on the biology, distribution, natural enemies, and biological control strategies of fall armyworm was synthesized and analyzed.The review revealed that fall armyworm possesses high reproductive capacity, broad host range, and strong dispersal ability, enabling rapid establishment in newly invaded regions. Several natural enemies were identified, including parasitoids, predators, bacteria, viruses, and entomopathogenic fungi. Key parasitoids such as Telenomus remus, Trichogramma pretiosum, Chelonus insularis, and Cotesia marginiventris were found to effectively suppress egg and larval populations. Entomopathogenic fungi including Beauveria bassiana and Metarhizium anisopliae demonstrated considerable pathogenicity, with reported mortality rates ranging from 30% to 87%. Predators such as Doru luteipes, ladybird beetles, ants, and carabid beetles also contributed significantly to reducing pest populations.The effectiveness of natural enemies was influenced by environmental conditions, habitat diversity, cropping systems, and pesticide use. Conservation agriculture, habitat management, and reduced reliance on broad-spectrum insecticides enhanced biological control performance. The review concludes that integrating parasitoids, predators, and microbial pathogens into integrated pest management programs provides a sustainable and environmentally friendly approach for managing fall armyworm populations while reducing dependence on synthetic pesticides and promoting long-term agricultural productivity.
Muhammadu Abdulmalik, Murtala Yusu, Abba Amiru Musa· Journal of Basics and Applie...· 0 citations
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