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Toshova TB, Velchev DI, Pilarska DK, Todorov IA, Esteves I, Barth M, Takov DI. Biocontrol potential of entomopathogenic nematodes against the grey maize weevil Tanymecus dilaticollis (Coleoptera: Curculionidae) adults. Biol Futur 2024; 75:219-233. [PMID: 38416361 DOI: 10.1007/s42977-024-00206-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 01/18/2024] [Indexed: 02/29/2024]
Abstract
The grey maize weevil, Tanymecus dilaticollis, is a polyphagous species, which is among the most important pests of maize in Southeastern Europe. The efficacy of commercial products with two species of entomopathogenic nematodes (EPNs), Steinernema carpocapsae and Heterorhabditis bacteriophora, was investigated against adults of the grey maize weevil under laboratory conditions. Nemastar®, containing S. carpocapsae was more effective on T. dilaticollis adults than Nematop® containing H. bacteriophora, when applied uniformly to the surface of the soil, on Petri dishes containing T. dilaticollis adults. Results showed that S. carpocapsae rates of 83-333 infective juveniles/adult caused > 94% mortality in T. dilaticollis adults, whereas H. bacteriophora caused 27-61%, adult mortality, after exposure of insects to the commercial products of EPNs for 15 days. The infection rates of EPNs increased with concentration applied and ranged from 70-83% and 19-64% for Nemastar® and Nematop®, respectively. Subsequent field and semi-field tests were conducted with Nemastar® (application rate of 50 million S. carpocapsae per 100 m2) in maize crops with biological (mycoinsecticide Naturalis®, biofungicides and fertilizers) and chemical seed treatment (Gaucho® FS 600; active ingredient: imidacloprid) in Knezha, Bulgaria. Nematodes were found only in the dead specimens, in open plots and cages sprayed with the commercial nematode product. Nematode sprayings contributed for higher maize yields in the open maize plots in the fields with different seed treatments. We suggest that the use of powder formulation of S. carpocapsae in combination with biologically treated maize seeds can contribute to minimize the use of chemical insecticides against the grey maize weevil. The results obtained can be used as a base to further tests to ascertain the efficacy of EPNs products before they can be recommended for use in the integrated approach to T. dilaticollis management.
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Affiliation(s)
- Teodora B Toshova
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000, Sofia, Bulgaria.
| | - Dimitar I Velchev
- Maize Research Institute, Agricultural Academy, 5835, Knezha, Bulgaria
| | - Daniela K Pilarska
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000, Sofia, Bulgaria
| | - Ivaylo A Todorov
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000, Sofia, Bulgaria
| | - Ivânia Esteves
- Centre for Functional Ecology, Associate Laboratory TERRA, Department of Life Sciences, University of Coimbra, 3000-456, Coimbra, Portugal
| | - Michael Barth
- e-nema Gesellschaft für Biotechnologie und biologischen Pflanzenschutz mbH, Klausdorfer Str. 28-36, 24223, Schwentinental, Germany
| | - Danail I Takov
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000, Sofia, Bulgaria
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Fallet P, Bazagwira D, Ruzzante L, Ingabire G, Levivier S, Bustos-Segura C, Kajuga J, Toepfer S, Turlings TCJ. Entomopathogenic nematodes as an effective and sustainable alternative to control the fall armyworm in Africa. PNAS NEXUS 2024; 3:pgae122. [PMID: 38628598 PMCID: PMC11020222 DOI: 10.1093/pnasnexus/pgae122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 03/12/2024] [Indexed: 04/19/2024]
Abstract
The recent invasion of the fall armyworm (FAW), a voracious pest, into Africa and Asia has resulted in unprecedented increases in insecticide applications, especially in maize cultivation. The health and environmental hazards posed by these chemicals have prompted a call for alternative control practices. Entomopathogenic nematodes are highly lethal to the FAWs, but their application aboveground has been challenging. In this study, we report on season-long field trials with an innocuous biodegradable gel made from carboxymethyl cellulose containing local nematodes that we specifically developed to target the FAW. In several Rwandan maize fields with distinct climatic conditions and natural infestation rates, we compared armyworm presence and damage in control plots and plots that were treated with either our nematode gel formulation, a commercial liquid nematode formulation, or the commonly used contact insecticide cypermethrin. The treatments were applied to the whorl of each plant, which was repeated three to four times, at 2-week intervals, starting when the plants were still seedlings. Although all three treatments reduced leaf damage, only the gel formulation decreased caterpillar infestation by about 50% and yielded an additional ton of maize per hectare compared with untreated plots. Importantly, we believe that the use of nematodes can be cost-effective, since we used nematode doses across the whole season that were at least 3-fold lower than their normal application against belowground pests. The overall results imply that precisely formulated and easy-to-apply nematodes can be a highly effective, affordable, and sustainable alternative to insecticides for FAW control.
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Affiliation(s)
- Patrick Fallet
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland
- CABI-Switzerland, c/o Plant Protection and Soil Conservation Directorate, HU-6800 Hodmezovasarhely, Hungary
| | - Didace Bazagwira
- Rwanda Agriculture and Animal Resources Development Board, Entomopathogenic Nematodes Production Facility, 5016 Rubona, Rwanda
| | - Livio Ruzzante
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland
| | - Geraldine Ingabire
- Rwanda Agriculture and Animal Resources Development Board, Entomopathogenic Nematodes Production Facility, 5016 Rubona, Rwanda
| | - Sacha Levivier
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland
| | - Carlos Bustos-Segura
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland
| | - Joelle Kajuga
- Rwanda Agriculture and Animal Resources Development Board, Entomopathogenic Nematodes Production Facility, 5016 Rubona, Rwanda
| | - Stefan Toepfer
- CABI-Switzerland, c/o Plant Protection and Soil Conservation Directorate, HU-6800 Hodmezovasarhely, Hungary
- MARA-CABI Joint Laboratory for Biosafety, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 1008641 Beijing, China
| | - Ted C J Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland
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Kanagendran A, Turlings TCJ. Cowpea volatiles induced by beet armyworm or fall armyworm differentially prime maize plants. JOURNAL OF PLANT PHYSIOLOGY 2024; 292:154164. [PMID: 38141481 DOI: 10.1016/j.jplph.2023.154164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 11/29/2023] [Accepted: 12/08/2023] [Indexed: 12/25/2023]
Abstract
Exposure to herbivore-induced plant volatiles (HIPVs) is known to enhance the defense responses in plants. This so-called priming effect has only been marginally studied in intercropping systems. We tested whether HIPVs from cowpea, which often serves as an intercrop alongside maize, can prime herbivore-induced volatile emissions in maize. Conventional volatile collection assays and real-time mass spectrometry revealed that maize plants that were exposed to HIPVs from cowpea infested with Spodoptera exigua caterpillars emitted more than control plants when they themselves were subsequently damaged by the same pest. The enhanced emission was only evident on the first day after infestation. Maize plants that were exposed to HIPVs from cowpea infested by S. frugiperda larvae showed no priming effect and released considerably less upon S. frugiperda infestation than upon S. exigua infestation. The latter may be explained by the fact that S. frugiperda is particularly well adapted to feed on maize and is known to suppress maize HIPV emissions. Our results imply that HIPVs from cowpea, depending on the inducing insect herbivore, may strongly prime maize plants. This deserves further investigation, also in other intercropping systems, as it can have important consequences for tritrophic interactions and crop protection.
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Affiliation(s)
- Arooran Kanagendran
- Fundamental and Applied Research in Chemical Ecology (FARCE) Lab, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland.
| | - Ted C J Turlings
- Fundamental and Applied Research in Chemical Ecology (FARCE) Lab, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland.
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Machado RAR, Bhat AH, Castaneda-Alvarez C, Půža V, San-Blas E. Photorhabdus aballayi sp. nov. and Photorhabdus luminescens subsp. venezuelensis subsp. nov., isolated from Heterorhabditis amazonensis entomopathogenic nematodes. Int J Syst Evol Microbiol 2023; 73. [PMID: 37171451 DOI: 10.1099/ijsem.0.005872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Six Gram-negative, rod-shaped bacterial strains isolated from Heterorhabditis amazonensis entomopathogenic nematodes were characterized to determine their taxonomic position. 16S rRNA and gyrB gene sequences indicate that they belong to the class Gammaproteobacteria, family Morganellaceae and genus Photorhabdus, and that some of them are conspecifics. Two of them, APURET and JART, were selected for further molecular characterization using whole genome- and whole-proteome-based phylogenetic reconstructions and sequence comparisons. Phylogenetic reconstructions using whole genome and whole proteome sequences show that strains APURET and JART are closely related to Photorhabdus luminescens subsp. luminescens ATCC 29999T and to P. luminescens subsp. mexicana MEX47-22T. Moreover, digital DNA-DNA hybridization (dDDH) values between APURET and P. luminescens subsp. luminescens ATCC 29999T, APURET and P. luminescens subsp. mexicana MEX47-22T, and APURET and JART are 61.6, 61.2 and 64.1 %, respectively. These values are below the 70 % divergence threshold that delimits prokaryotic species. dDDH scores between JART and P. luminescens subsp. luminescens ATCC 29999T and between JART and P. luminescens subsp. mexicana MEX47-22T are 71.9 and 74.8 %, respectively. These values are within the 70 and 79 % divergence thresholds that delimit prokaryotic subspecies. Based on these genomic divergence values, APURET and JART represent two different taxa, for which we propose the names: Photorhabdus aballayi sp. nov. with APURET (=CCM 9236T =CCOS 2019T) as type strain and Photorhabdus luminescens subsp. venezuelensis subsp. nov. with JART (=CCM 9235T =CCOS 2021T) as type strain. Our study contributes to a better understanding of the biodiversity of an important bacterial group with enormous biotechnological and agricultural potential.
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Affiliation(s)
- Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
- Department of Biosciences, University Center for Research and Development, Chandigarh University, Gharuan, Mohali, 140413, Punjab, India
| | - Carlos Castaneda-Alvarez
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas. Universidad de Chile, Santiago, Chile
| | - Vladimir Půža
- Biology Centre CAS, Institute of Entomology, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic
| | - Ernesto San-Blas
- Instituto de Ciencias Agroalimentarias, Animales y Ambientales (ICA3), Universidad de O'Higgins, San Fernando, Chile
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Chen Y, Long H, Jin T, Peng Z, Sun Y, Feng T. Potential of Entomopathogenic Nematode HbSD as a Candidate Biocontrol Agent against Spodoptera frugiperda. INSECTS 2022; 14:2. [PMID: 36661931 PMCID: PMC9866796 DOI: 10.3390/insects14010002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Spodoptera frugiperda is a highly destructive and polyphagous pest that causes severe damage to various crops, especially maize. The wide use of chemical insecticides to control S. frugiperda results in resistance against commonly used chemicals and resistant mutations will expand in populations accompanied by a spread to vulnerable areas. Consequently, more effective and friendly strategies must be explored to minimize losses caused by S. frugiperda. Entomopathogenic nematodes (EPN) are good candidates for the biological control of different species of insect pests, including S. frugiperda. In the current study, the infective capabilities of the EPN species HbSD, belonging to Hetrerorhabditis bacteriophora, were evaluated against S. frugiperda under laboratory, greenhouse and field conditions. In laboratory assays, HbSD was highly virulent against 3rd/5th instar larvae, which was related to HbSD concentration and exposure durations. In greenhouse assays, spraying aqueous HbSD also showed good performance in killing larvae on maize leaves. However, the virulence of HbSD decreased in field trials where many adverse factors affecting survival and efficacy were encountered by HbSD. Overall, our study provides an alternative EPN for the biological control of S. frugiperda with the potential to be developed as a sustainable option for efficient pest management.
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Affiliation(s)
- Yuan Chen
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Haibo Long
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
- Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, China
| | - Tao Jin
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Zhengqiang Peng
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Yanfang Sun
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Tuizi Feng
- Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
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Babendreier D, Toepfer S, Bateman M, Kenis M. Potential Management Options for the Invasive Moth Spodoptera frugiperda in Europe. JOURNAL OF ECONOMIC ENTOMOLOGY 2022; 115:1772-1782. [PMID: 36515106 PMCID: PMC9748578 DOI: 10.1093/jee/toac089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Indexed: 06/17/2023]
Abstract
We here review and discuss management options that growers in Europe could take in response to the expected invasion of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae). The focus is put on maize but the information provided is also relevant for other crops potentially affected. A sound forecasting system for fall armyworm both on a regional as well as at local scale should be established to alert growers as early as possible. Whilst a number of cultural control methods are adopted by maize growers in different regions globally to fight fall armyworm, many of them may either not be highly effective, too laborious, or otherwise unfeasible within the mechanized crop production systems used in Europe. Potential is seen in the stimulation of natural enemies through conservation biocontrol approaches, e.g., the planting of flower strips or intermediate cover crops, reducing tillage intensity, and avoiding broad-spectrum insecticides. To manage fall armyworm infestations, several effective biologically-based products are available globally, and some in Europe, e.g., based on specific baculoviruses, certain Bacillus thuringiensis strains, few entomopathogenic nematodes, and a number of botanicals. These should be given priority to avoid a major influx of insecticides into the maize agro-ecosystem once the fall armyworm arrives and in case growers are not prepared. Plant protection companies, particularly biocontrol companies should act proactively in starting registration of ingredients and products against fall armyworm in Europe. European maize growers should be made aware, in time, of key features of this new invasive pest and appropriate control options.
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Affiliation(s)
| | - Stefan Toepfer
- CABI Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland
| | - Melanie Bateman
- CABI Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland
| | - Marc Kenis
- CABI Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland
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Steinernema africanum n. sp. (Rhabditida, Steinernematidae), a New Entomopathogenic Nematode Species Isolated in the Republic of Rwanda. J Nematol 2022; 54:20220049. [DOI: 10.2478/jofnem-2022-0049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Indexed: 11/06/2022] Open
Abstract
Abstract
Alternatives to hazardous insecticides are urgently needed for an environmentally friendly and effective management of insect pests. One such option is the use of entomopathogenic nematodes (EPN). To increase the availability of EPN with potential for biocontrol, we surveyed agricultural soils in the Republic of Rwanda and collected two Steinernema isolates. Initial molecular characterization showed that they represent a new species, for which we propose the name S. africanum n. sp. To describe this new species, we reconstructed phylogenetic relationships, calculated sequence similarity scores, characterized the nematodes at the morphological level, conducted crossing experiments, and isolated and characterized their symbiotic bacteria. At the molecular level, S. africanum n. sp. is closely related to S. litorale and S. weiseri. At the morphological level, S. africanum n. sp. differs from closely related species by the position of the nerve ring and also because the stoma and pharynx region is longer. The first-generation males have ventrally curved spicules with lanceolate manubrium and fusiform gubernaculum and the second-generation males have rounded manubrium and anteriorly hook-like gubernaculum. Steinernema africanum n. sp. does not mate or produce fertile progeny with any of the closely related species.
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