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Maingi FM, Akutse KS, Ajene IJ, Omolo KM, Khamis FM. Immunological responses and gut microbial shifts in Phthorimaea absoluta exposed to Metarhizium anisopliae isolates under different temperature regimes. Front Microbiol 2023; 14:1258662. [PMID: 38029135 PMCID: PMC10666277 DOI: 10.3389/fmicb.2023.1258662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
The invasive tomato leaf miner, Phthorimaea absoluta, is conventionally controlled through chemical insecticides. However, the rise of insecticide resistance has necessitated sustainable and eco-friendly alternatives. Entomopathogenic fungi (EPF) have shown potential due to their ability to overcome resistance and have minimal impact on non-target organisms. Despite this potential, the precise physiological mechanisms by which EPF acts on insect pests remain poorly understood. To attain a comprehensive understanding of the complex physiological processes that drive the successful control of P. absoluta adults through EPF, we investigated the impacts of different Metarhizium anisopliae isolates (ICIPE 665, ICIPE 20, ICIPE 18) on the pest's survival, cellular immune responses, and gut microbiota under varying temperatures. The study unveiled that ICIPE 18 caused the highest mortality rate among P. absoluta moths, while ICIPE 20 exhibited the highest significant reduction in total hemocyte counts after 10 days at 25°C. Moreover, both isolates elicited notable shifts in P. absoluta's gut microbiota. Our findings revealed that ICIPE 18 and ICIPE 20 compromised the pest's defense and physiological functions, demonstrating their potential as biocontrol agents against P. absoluta in tomato production systems.
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Affiliation(s)
- Felix Muendo Maingi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Komivi Senyo Akutse
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Unit for Environment Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Inusa Jacob Ajene
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Kevin Mbogo Omolo
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
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Onsongo SK, Mohamed SA, Akutse KS, Gichimu BM, Dubois T. The Entomopathogenic Fungi Metarhizium anisopliae and Beauveria bassiana for Management of the Melon Fly Zeugodacus cucurbitae: Pathogenicity, Horizontal Transmission, and Compatability with Cuelure. INSECTS 2022; 13:859. [PMID: 36292807 PMCID: PMC9604353 DOI: 10.3390/insects13100859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/06/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
In the laboratory, the pathogenicity of thirteen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and two isolates of Beauveria bassiana (Balsamo) Vuillemin against the melon fly Zeugodacus cucurbitae (Coquillett) were assessed by exposing adults to 0.3 g of dry conidia (~3 × 109 conidia) of each isolate for 5 min and monitoring mortality for up to 5 days. Compatibility with a male pheromone, cuelure, (4-(p-acetoxyphenyl)-2-butanone), was determined by testing conidial germination and germ tube growth of the most promising isolate, M. anisopliae ICIPE 69, in the presence of cuelure at different temperatures. For horizontal transmission, the flies were separated by sex, separately exposed to M. anisopliae ICIPE 69, and subsequently mixed with non-exposed flies from the other sex. The most pathogenic isolates were M. anisopliae ICIPE 69, 18, and 30, causing mortalities of 94, 87, and 81%, with 5 days post-exposure, respectively. Metarhizium anisopliae ICIPE 69 caused the highest pupal mortality of 74%, with 15 days post-exposure. Horizontal transmission of M. anisopliae ICIPE 69 among male and female Z. cucurbitae was confirmed by 59 and 67% mortality after exposure to infected donor males and females, respectively. Metarhizium anisopliae ICIPE 69 affected the oviposition, but not hatchability, of infected Z. cucurbitae females. Metarhizium anisopliae ICIPE 69 is, therefore, a potential isolate for biopesticide development for Z. cucurbitae management in cucurbit production systems.
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Affiliation(s)
- Susan K. Onsongo
- International Centre of Insect Physiology and Ecology (icipe), Nairobi 00100, Kenya
- Department of Agricultural Resource Management, University of Embu, Embu 60100, Kenya
| | - Samira A. Mohamed
- International Centre of Insect Physiology and Ecology (icipe), Nairobi 00100, Kenya
| | - Komivi S. Akutse
- International Centre of Insect Physiology and Ecology (icipe), Nairobi 00100, Kenya
| | - Bernard M. Gichimu
- Department of Agricultural Resource Management, University of Embu, Embu 60100, Kenya
| | - Thomas Dubois
- International Centre of Insect Physiology and Ecology (icipe), Nairobi 00100, Kenya
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Paradza VM, Khamis FM, Yusuf AA, Subramanian S, Akutse KS. Efficacy of Metarhizium anisopliae and ( E)-2-hexenal combination using autodissemination technology for the management of the adult greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae). FRONTIERS IN INSECT SCIENCE 2022; 2:991336. [PMID: 38646071 PMCID: PMC11027017 DOI: 10.3389/finsc.2022.991336] [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: 07/11/2022] [Accepted: 08/24/2022] [Indexed: 04/23/2024]
Abstract
The efficiency of an autodissemination technique in controlling adult whiteflies, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) on tomato, Solunum lycopersicum was investigated with previously identified potent fungal isolates of Metarhizium anisopliae ICIPE 18, ICIPE 62 and ICIPE 69 under screenhouse or semi-field conditions. The autodissemination device was inoculated with dry conidia of the M. anisopliae isolates, while control insects were exposed to a fungus-free device. Sampling for conidia uptake, conidial viability and persistence, and insect mortality was done at 1, 2, 3, 5 and 8 days post-exposure, and collected insects were monitored for mortality over ten days. Overall, mortality was higher in insects exposed to ICIPE 18 (62.8%) and ICIPE 69 (61.8%) than in those exposed to ICIPE 62 (42.6%), with median lethal times, (LT50) ranging between 6.73-8.54 days. The control group recorded the lowest mortality rates (18.9%). A general linear reduction in conidial viability with exposure time was observed, although this was more pronounced with M. anisopliae ICIPE 62. Insects exposed to M. anisopliae ICIPE 69 also recorded the highest conidia uptake, hence selected for further evaluation with a T. vaporariorum attractant volatile organic compound, (E)-2-hexenal. The volatile inhibited fungal germination in laboratory compatibility tests, therefore, spatial separation of M. anisopliae ICIPE 69 and (E)-2-hexenal in the autodissemination device was conducted. The inhibitory effects of the volatile were significantly reduced by spatial separation at a distance of 5 cm between the fungus and the volatile, which was found to be more suitable and chosen for the subsequent experiments. Results showed that (E)-2-hexenal did not influence conidia uptake by the insects, while fungal viability and the subsequent mortality variations were more related to duration of exposure. The fungus-volatile compatibility demonstrated with spatial separation provides a basis for the optimisation of the volatile formulation to achieve better T. vaporariorum suppression with an excellent autodissemination efficiency when used in the management of whiteflies under screenhouse conditions.
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Affiliation(s)
- Vongai M. Paradza
- Plant Health Theme, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Fathiya M. Khamis
- Plant Health Theme, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Abdullahi A. Yusuf
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
- Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Hatfield, South Africa
| | - Sevgan Subramanian
- Plant Health Theme, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Komivi S. Akutse
- Plant Health Theme, International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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Bhadani RV, Gajera HP, Hirpara DG, Savaliya DD, Anuj SA. Biosynthesis and characterization of extracellular metabolites-based nanoparticles to control the whitefly. Arch Microbiol 2022; 204:311. [PMID: 35538378 DOI: 10.1007/s00203-022-02917-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 03/19/2022] [Accepted: 04/13/2022] [Indexed: 11/02/2022]
Abstract
The Beauveria spp. were isolated from soil and insect cadavers and confirmed as Beauveria bassiana by molecular identification using a specific primer. The bioefficacy of 14 B. bassiana against whiteflies indicated the highest percent mortality in JAU2, followed by JAU1. The LC50 and LC90 values were found to be 0.043 × 105 and 0.05 × 1014 conidia.ml-1, respectively, in JAU2. Extracellular metabolites of B.bassiana are derived and used for the green synthesis of silver nanoparticles (AgNPs). The synthesized green AgNPs were characterized for size (24.8 nm), shape (scanning electron microscopy), stability (200 mV zeta), and purity (energy-dispersive X-ray spectroscopy, 3 keV). A total of 63 extracellular metabolites were identified using LC-MS/QTOF in potent JAU2 with recognition of alcohols, phenols, carboxylic acids, amines, alkynes, and amides as functional groups. The functional groups of green AgNPs were also confirmed in Fourier transforms infrared spectroscopy (FTIR) with the specific spectra in the electromagnetic spectrum. The relationship between identified metabolites of antagonist and the FTIR spectrum of the functional group indicated the involvement of extracellular novel compounds, viz., homoisocitrate, aconitine, phodexin A, capillone, solanocapsine, and anethole in the synthesis of green AgNPs. The efficacy of green AgNPs on whiteflies suggested that corrected percent mortality was observed at 60 µg Ag.ml-1 at 120 h, which corresponds to the LC50 value (66.42 µg Ag.ml-1). Results were interpreted to show that green AgNPs synthesized from extracellular metabolites of B.bassiana JAU2 gave better insecticidal activity at LC50 as compared to live antagonist JAU2.
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Affiliation(s)
- Rushita V Bhadani
- Department of Biotechnology, College of Agriculture, Junagadh Agricultural University, Junagadh, 362 001, Gujarat, India
| | - H P Gajera
- Department of Biotechnology, College of Agriculture, Junagadh Agricultural University, Junagadh, 362 001, Gujarat, India.
| | - Darshna G Hirpara
- Department of Biotechnology, College of Agriculture, Junagadh Agricultural University, Junagadh, 362 001, Gujarat, India
| | - D D Savaliya
- Department of Biotechnology, College of Agriculture, Junagadh Agricultural University, Junagadh, 362 001, Gujarat, India
| | - Samir A Anuj
- Department of Biotechnology, College of Agriculture, Junagadh Agricultural University, Junagadh, 362 001, Gujarat, India
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Kenis M, Agboyi LK, Adu-Acheampong R, Ansong M, Arthur S, Attipoe PT, Baba ASM, Beseh P, Clottey VA, Combey R, Dzomeku I, Eddy-Doh MA, Fening KO, Frimpong-Anin K, Hevi W, Lekete-Lawson E, Nboyine JA, Ohene-Mensah G, Oppong-Mensah B, Nuamah HSA, van der Puije G, Mulema J. Horizon scanning for prioritising invasive alien species with potential to threaten agriculture and biodiversity in Ghana. NEOBIOTA 2022. [DOI: 10.3897/neobiota.71.72577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Invasive alien species (IAS) continue to shape the global landscape through their effects on biological diversity and agricultural productivity. The effects are particularly pronounced in Sub-Saharan Africa, which has seen the arrival of many IAS in recent years. This has been attributed to porous borders, weak cross border biosecurity, and inadequate capacity to limit or stop invasions. Prediction and early detection of IAS, as well as mechanisms of containment and eradication, are needed in the fight against this global threat. Horizon scanning is an approach that enables gathering of information on risk and impact that can support IAS management. A study was conducted in Ghana to establish two ranked lists of potential invasive alien plant pest species that could be harmful to agriculture, forestry, and the environment, and to rank them according to their potential threat. The ultimate objective was to enable prioritization of actions including pest risk analysis, prevention, surveillance and contingency plans. Prioritisation was carried out using an adapted version of horizon scanning and consensus methods developed for ranking IAS worldwide. Following a horizon scan of invasive alien species not yet officially present in Ghana, a total of 110 arthropod and 64 pathogenic species were assessed through a simplified pest risk assessment. Sixteen species, of which 14 were arthropods and two pathogens, had not been recorded on the African continent at the time of assessment. The species recorded in Africa included 19 arthropod and 46 pathogenic species which were already recorded in the neighbouring countries of Burkina Faso, Côte d’Ivoire, and Togo. The majority of arthropod species were likely to arrive as contaminants on commodities, followed by a sizable number which were likely to arrive as stowaways, while some species were capable of long distance dispersal unaided. The main actions suggested for species that scored highly included full pest risk analyses and, for species recorded in neighbouring countries, surveys to determine their presence in Ghana were recommended.
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Agbessenou A, Akutse KS, Yusuf AA, Wekesa SW, Khamis FM. Temperature-dependent modelling and spatial prediction reveal suitable geographical areas for deployment of two Metarhizium anisopliae isolates for Tuta absoluta management. Sci Rep 2021; 11:23346. [PMID: 34857835 PMCID: PMC8639720 DOI: 10.1038/s41598-021-02718-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 11/22/2021] [Indexed: 11/30/2022] Open
Abstract
Tuta absoluta is one of the most devastating pests of Solanaceae crops in Africa. We previously demonstrated the efficacy of Metarhizium anisopliae isolates ICIPE 18, ICIPE 20 and ICIPE 665 against adult T. absoluta. However, adequate strain selection and accurate spatial prediction are fundamental to optimize their efficacy and formulations before field deployment. This study therefore assessed the thermotolerance, conidial yield and virulence (between 15 and 35 °C) of these potent isolates. Over 90% of conidia germinated at 20, 25 and 30 °C while no germination occurred at 15 °C. Growth of the three isolates occurred at all temperatures, but was slower at 15, 33 and 35 °C as compared to 20, 25 and 30 °C. Optimum temperatures for mycelial growth and spore production were 30 and 25 °C, respectively. Furthermore, ICIPE 18 produced higher amount of spores than ICIPE 20 and ICIPE 665. The highest mortality occurred at 30 °C for all the three isolates, while the LT50 values of ICIPE 18 and ICIPE 20 were significantly lower at 25 and 30 °C compared to those of ICIPE 665. Subsequently, several nonlinear equations were fitted to the mortality data to model the virulence of ICIPE 18 and ICIPE 20 against adult T. absoluta using the Entomopathogenic Fungi Application (EPFA) software. Spatial prediction revealed suitable locations for ICIPE 18 and ICIPE 20 deployment against T. absoluta in Kenya, Tanzania and Uganda. Our findings suggest that ICIPE 18 and ICIPE 20 could be considered as effective candidate biopesticides for an improved T. absoluta management based on temperature and location-specific approach.
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Affiliation(s)
- Ayaovi Agbessenou
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya.,Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Komivi S Akutse
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya.
| | - Abdullahi A Yusuf
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.,Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Sospeter W Wekesa
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Fathiya M Khamis
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya
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Paradza VM, Khamis FM, Yusuf AA, Subramanian S, Akutse KS. Virulence and horizontal transmission of Metarhizium anisopliae by the adults of the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) and the efficacy of oil formulations against its nymphs. Heliyon 2021; 7:e08277. [PMID: 34765790 PMCID: PMC8571502 DOI: 10.1016/j.heliyon.2021.e08277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/08/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
The pathogenicity of dry conidia and fungal suspensions of 16 entomopathogenic fungal isolates (10 Metarhizium anisopliae and six Beauveria bassiana) was evaluated against adults and second instar nymphs of the greenhouse whitefly, Trialeurodes vaporariorum respectively. All the tested isolates were pathogenic to T. vaporariorum and caused mortality of 45-93% against the adults and 24-89% against the nymphs. However, M. anisopliae strains showed higher virulence to both developmental stages as compared to B. bassiana strains. The three most virulent isolates that caused high mortalities in adults were M. anisopliae ICIPE 18, ICIPE 62 and ICIPE 69, with cumulative mortalities of 82, 91 and 93%, and median lethal times (LT50) of 5.20, 5.05 and 4.78 days, respectively. These isolates were further assessed for spore acquisition and retention by the adult insects at 0, 24, 48 and 72 h after exposure to dry conidia spores. There was no significant difference among isolates on their acquisition by the insects, although the effect of time on the number of spores retained by each insect was significant. For M. anisopliae ICIPE 62 and ICIPE 69, spore number was significantly higher immediately after exposure at 0 h than at 24, 48 and 72 h, whereas for M. anisopliae ICIPE 18, the spore number remained constant for all the days. The infected "donor" insects were able to horizontally transmit the acquired spores to uninfected "recipient" insects causing high mortality rates in both donor and recipient groups. Metarhizium anisopliae ICIPE 7, ICIPE 18 and ICIPE 62 were the most virulent isolates against the nymphs in aqueous formulation during the first screening with >80% mortality. However, in 2% (v/v) oil formulations at 1 × 108 conidia/ml, canola formulated ICIPE 62, ICIPE 18 and olive formulated ICIPE 18 were the most effective, resulting in 87.8, 88.1 and 99.4% nymphal mortalities respectively and with lower LT50. Oil formulations significantly enhanced the efficacy and virulence of the isolates against the nymphs compared to aqueous formulations.
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Affiliation(s)
- Vongai M. Paradza
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Fathiya M. Khamis
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Abdullahi A. Yusuf
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
- Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Sevgan Subramanian
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Komivi S. Akutse
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
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Mechanism of Action of Endophytic Fungi Hypocrea lixii and Beauveria bassiana in Phaseolus vulgaris as Biopesticides against Pea Leafminer and Fall Armyworm. Molecules 2021; 26:molecules26185694. [PMID: 34577165 PMCID: PMC8471441 DOI: 10.3390/molecules26185694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/12/2021] [Accepted: 09/14/2021] [Indexed: 11/17/2022] Open
Abstract
Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm.
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Akutse KS, Khamis FM, Ambele FC, Kimemia JW, Ekesi S, Subramanian S. Combining insect pathogenic fungi and a pheromone trap for sustainable management of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae). J Invertebr Pathol 2020; 177:107477. [PMID: 33053399 DOI: 10.1016/j.jip.2020.107477] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/14/2020] [Accepted: 09/22/2020] [Indexed: 11/25/2022]
Abstract
Fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a key invasive pest of maize and other crops in Africa. Entomopathogenic fungi play an important role in regulating the immature stages of this invasive pest as opposed to synthetic pesticides that are hazardous to human, environment and biodiversity. To tackle the adult stage of the pest (the moth) and to improve on the application strategy of the fungal-based biopesticides, this study evaluated the effect of various entomopathogenic fungi isolates on S. frugiperda moths. Twenty-two isolates (16 Metarhizium anisopliae and 6 Beauveria bassiana) were screened in the laboratory to assess their pathogenicity and virulence against S. frugiperda moths. The compatibility of the most pathogenic isolates with S. frugiperda pheromone FALLTRACT lure, the horizontal transmission of the inoculum among S. frugiperda moths, and the effect on oviposition were also determined under laboratory conditions. All 22 fungal isolates screened were pathogenic to the moths, but the mortality varied significantly among the isolates (P < 0.0001) seven days post-treatment. Beauveria bassiana ICIPE 621 and M. anisopliae ICIPE 7 outperformed all the other isolates by causing 100% mortality of the moths with the lowest LT50 values of 3.6 ± 0.1 and 3.9 ± 0.0 days, respectively. Both isolates were also found compatible with FALLTRACT lure, as the lure had no effect on the conidial germination in the laboratory. Male and female moths were able to horizontally transmit conidia of both fungal isolates to untreated moths, causing high mortality of S. frugiperda in 'donor' and 'recipient' groups. In addition, the oviposition, hatchability of eggs and longevity of larvae were significantly affected on the fungal infected females. Although single moths still retained high conidial numbers 72 h post-inoculation, the number of conidia decreased with time. These results suggest that ICIPE 7 and ICIPE 621 could be used in combination with S. frugiperda pheromone in an autodissemination approach to suppress S. frugiperda population.
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Affiliation(s)
- Komivi S Akutse
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
| | - Fathiya M Khamis
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Felicitas C Ambele
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya; Food Security and Safety, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2745, South Africa
| | - Jane W Kimemia
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Sunday Ekesi
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Sevgan Subramanian
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
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Akutse KS, Subramanian S, Maniania NK, Dubois T, Ekesi S. Biopesticide Research and Product Development in Africa for Sustainable Agriculture and Food Security – Experiences From the International Centre of Insect Physiology and Ecology (icipe). FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.563016] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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van Tol RWHM, Davidson MM, Butler RC, Teulon DAJ, de Kogel WJ. Visually and olfactorily enhanced attractive devices for thrips management. ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA 2020; 168:665-677. [PMID: 33149364 PMCID: PMC7594531 DOI: 10.1111/eea.12969] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 06/15/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
'Lure-and-infect' is an insect pest management strategy with high potential but so far there are few examples of its application. Using traps as surrogates for auto-dissemination devices, we tested the attractiveness to naturally occurring thrips (Thysanoptera: Thripidae) of three trap types differing in colour and structure, with and without the thrips lure methyl isonicotinate (MI), and sticky plate traps as a control. The aim was to find more effective traps that could be further developed into devices for auto-dissemination and lure-and-infect of thrips. The number of thrips captured varied substantially with trap type and the presence of the MI lure. We found a high visual response to a sticky 'white ruffle' trap (i.e., a 30-cm-long cylindrical outline of folded fabric), compared to a commonly used blue sticky plate trap (Bug-scan) as the control. This effect was seen both in a greenhouse with roses (Rosa spp.), where we encountered western flower thrips, Frankliniella occidentalis (Pergande), and in a grass field, where we encountered onion thrips, Thrips tabaci Lindeman, and New Zealand flower thrips, Thrips obscuratus (Crawford). In the absence of MI, the white ruffle trap caught 7-22× more thrips than the control Bug-scan trap. A similarly designed blue ruffle trap and a modified Lynfield trap caught lower thrips numbers than the white ruffle and the control Bug-scan traps. Presence of MI substantially increased the captures of T. tabaci in all three trap types in the field (2.5-18×). In the greenhouse, without MI the white ruffle trap caught 3.5-14× more thrips than the Bug-scan, blue ruffle, or modified Lynfield traps. Presence of MI increased the captures of F. occidentalis males and females in the Lynfield and blue ruffle traps (1.4-2.8×), but not in the white ruffle trap in the greenhouse (ca. 1.1×). The importance of visual and olfactory factors for the design of effective auto-dissemination and lure-and-infect strategies for thrips management is discussed.
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Affiliation(s)
| | - Melanie M. Davidson
- New Zealand Institute for Plant and Food Research LimitedPrivate Bag 4704ChristchurchNew Zealand
| | - Ruth C. Butler
- New Zealand Institute for Plant and Food Research LimitedPrivate Bag 4704ChristchurchNew Zealand
| | - David A. J. Teulon
- New Zealand Institute for Plant and Food Research LimitedPrivate Bag 4704ChristchurchNew Zealand
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McGuire AV, Northfield TD. Tropical Occurrence and Agricultural Importance of Beauveria bassiana and Metarhizium anisopliae. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.00006] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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Srinivasan R, Sevgan S, Ekesi S, Tamò M. Biopesticide based sustainable pest management for safer production of vegetable legumes and brassicas in Asia and Africa. PEST MANAGEMENT SCIENCE 2019; 75:2446-2454. [PMID: 31074055 DOI: 10.1002/ps.5480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/27/2019] [Accepted: 05/04/2019] [Indexed: 06/09/2023]
Abstract
Vegetables are one of the important crops which could alleviate poverty and malnutrition among the smallholder farmers in tropical Asia and Africa. However, a plethora of pests limit the productivity of these crops, leading to economic losses. Vegetable producers overwhelmingly rely on chemical pesticides in order to reduce pest-caused economic losses. However, over-reliance on chemical pesticides poses serious threats to human and environmental health. Hence, biopesticides offer a viable alternative to chemical pesticides in sustainable pest management programs. Baculoviruses such as nucleopolyhedrovirus (NPV) and granulovirus (GV) have been exploited as successful biological pesticides in agriculture, horticulture and forestry. Maruca vitrata multiple nucleocapsid NPV (MaviMNPV) was found to be a unique baculovirus specifically infecting pod borer on food legumes, and it has been successfully developed as a biopesticide in Asia and Africa. Entomopathogenic fungi also offer sustainable pest management options. Several strains of Metarhizium anisopliae and Beauveria bassiana have been tested and developed as biopesticides in Asia and Africa. This review specifically focuses on the discovery and development of entomopathogenic virus and fungi-based biopesticides against major pests of vegetable legumes and brassicas in Asia and Africa. © 2019 Society of Chemical Industry.
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Affiliation(s)
| | | | - Sunday Ekesi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Manuele Tamò
- International Institute of Tropical Agriculture, Cotonou, Benin
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Horizontal transmission of Metarhizium anisopliae between Spoladea recurvalis (Lepidoptera: Crambidae) adults and compatibility of the fungus with the attractant phenylacetaldehyde. Microb Pathog 2019; 131:197-204. [DOI: 10.1016/j.micpath.2019.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/08/2019] [Accepted: 04/06/2019] [Indexed: 11/19/2022]
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Kaur M, Chadha P, Kaur S, Kaur A, Kaur R, Yadav AK, Kaur R. Evaluation of genotoxic and cytotoxic effects of ethyl acetate extract of Aspergillus flavus on Spodoptera litura. J Appl Microbiol 2019; 126:881-893. [PMID: 30216609 DOI: 10.1111/jam.14105] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/28/2018] [Accepted: 09/03/2018] [Indexed: 01/31/2023]
Abstract
AIM Recent concerns about the possible adverse effects of agricultural chemicals on health and environment have generated a considerable interest in biological alternatives. This study aimed to test the insecticidal potential of fungus Aspergillus flavus and revealed its genotoxic and cytotoxic effects using Spodoptera litura (Fabricius) as a model. METHODS AND RESULTS The fungus was isolated from the surface of the dead insect and investigated for its insecticidal potential against S. litura by bioassay studies. Significant increase in mortality, prolonged development period and reduced adult emergence in S. litura were observed in larva fed on diet supplemented with fungal extract. In addition, fungus was also found to cause oxidative stress, DNA damage and cell death. Significantly higher percentages of necrotic cells and DNA damage were observed in larvae treated with fungal extract. Furthermore, DNA repair studies predicted the longevity of toxic effects induced by fungus. Phytochemical and ultra-high performance liquid chromatography studies revealed the presence of phenolic compounds in the extract and liquid chromatography-mass spectrometry indicated it to be a non-aflatoxin strain of A. flavus. Fungal extract was less toxic to mammalian cell lines as compared to cytotoxic drug doxorubicin (DOX) in the MTT assay. CONCLUSION The study highlights the insecticidal potential of A. flavus by revealing its genotoxicity and cytotoxicity causing potential. This is the first report showing the genotoxic and cytotoxic effects of the fungus A. flavus on S. litura. SIGNIFICANCE AND IMPACT OF THE STUDY The study provides a useful insight to explore microbial agents as biopesticides in order to reduce various environmental as well as human health problems due to synthetic pesticides.
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Affiliation(s)
- M Kaur
- Department of Zoology, Guru Nanak Dev University, Amritsar, India
| | - P Chadha
- Department of Zoology, Guru Nanak Dev University, Amritsar, India
| | - S Kaur
- Department of Zoology, Guru Nanak Dev University, Amritsar, India
| | - A Kaur
- Departments of Microbiology, Guru Nanak Dev University, Amritsar, India
| | - R Kaur
- Departments of Microbiology, Guru Nanak Dev University, Amritsar, India
| | - A K Yadav
- Department of Biotechnology, Guru Nanak Dev University, Amritsar, India
| | - R Kaur
- Department cum National Centre for Human Genome Studies and Research, Panjab University, Chandigarh, India
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Dembilio Ó, Moya P, Vacas S, Ortega-García L, Quesada-Moraga E, Jaques JA, Navarro-Llopis V. Development of an attract-and-infect system to control Rhynchophorus ferrugineus with the entomopathogenic fungus Beauveria bassiana. PEST MANAGEMENT SCIENCE 2018; 74:1861-1869. [PMID: 29427377 DOI: 10.1002/ps.4888] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 01/29/2018] [Accepted: 02/04/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND A new Beauveria bassiana-based attract and infect device (AID) to control Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) was developed. The virulence and persistence of the fungal formulation used in the AID were evaluated in the laboratory. Semi-field and field trials were carried out to validate the results and establish the potential of this device as a control tool. RESULTS In laboratory conditions, a 50% lethal time (LT50 ) of 4.33 days was obtained when adults (7-10 days old) were exposed to the inoculation tunnel (IT) containing 1 × 1010 conidia g-1 in an oil-based fungal formulation. This formulation maintained conidium viability at 50% for up to 2 months. Moreover, when adults were exposed to 2.5-month field-aged ITs, mortality still reached 50% 40 days after exposure. In addition, no differences were observed between ITs aged in early spring and those aged in summer, suggesting that the fungal formulation is not strongly affected by environmental factors in Mediterranean basin conditions. Semi-field assays showed that the device allowed an easy transit of weevils through the IT, which were effectively attracted and infected. Using the AIDs in 4-ha plot field trials, a reduction of >50% in the percentage of infested sentinel palms was obtained. CONCLUSION Based on the results obtained in terms of the efficacy and persistence of this new AID in the field and its potential in reducing R. ferrugineus populations and palm infestation, this device could become a key tool for the management of R. ferrugineus. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Óscar Dembilio
- Universitat Jaume I (UJI), Unitat Associada d'Entomologia Agrícola UJI-IVIA (Institut Valencià d'Investigacions Agràries), Departament de Ciències Agràries i del Medi Natural, Castelló de la Plana, Spain
| | - Pilar Moya
- Universitat Politècnica de València, Instituto Agroforestal del Mediterráneo, Valencia, Spain
| | - Sandra Vacas
- Universitat Politècnica de València, Instituto Agroforestal del Mediterráneo, Valencia, Spain
| | - Lola Ortega-García
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Cordoba, Spain
| | - Enrique Quesada-Moraga
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Cordoba, Spain
| | - Josep A Jaques
- Universitat Jaume I (UJI), Unitat Associada d'Entomologia Agrícola UJI-IVIA (Institut Valencià d'Investigacions Agràries), Departament de Ciències Agràries i del Medi Natural, Castelló de la Plana, Spain
| | - Vicente Navarro-Llopis
- Universitat Politècnica de València, Instituto Agroforestal del Mediterráneo, Valencia, Spain
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Becher PG, Jensen RE, Natsopoulou ME, Verschut V, De Fine Licht HH. Infection of Drosophila suzukii with the obligate insect-pathogenic fungus Entomophthora muscae. JOURNAL OF PEST SCIENCE 2018; 91:781-787. [PMID: 29568251 PMCID: PMC5847158 DOI: 10.1007/s10340-017-0915-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/21/2017] [Accepted: 08/31/2017] [Indexed: 05/05/2023]
Abstract
Physiological constraints restrict specialist pathogens from infecting new hosts. From an applied perspective, a narrow host range makes specialist pathogens interesting for targeting specific pest insects since they have minimal direct effects on non-target species. Entomopathogenic fungi of the genus Entomophthora are dipteran-specific but have not been investigated for their ability to infect the spotted wing drosophila (SWD; Drosophila suzukii) a fruit-damaging pest invasive to Europe and America. Our main goal was to study whether SWD is in the physiological host range of the entomophthoralean species E. muscae. We investigated pathogenicity and virulence of E. muscae towards its main natural host, the housefly Musca domestica, and towards SWD. We found that E. muscae readily infected and significantly reduced survival of SWD by 27.3% with the majority of flies dying 4-8 days post-exposure. In comparison with SWD, infection of the natural host M. domestica resulted in an even higher mortality of 62.9% and larger conidial spores of E. muscae, reflecting the physiological constraints of the pathogen in the atypical host. We demonstrated that pathogens of the E. muscae species complex that typically have a narrow natural host range of one or few dipteran species are able to infect SWD, and we described a new method for in vivo transmission and infection of an entomophthoralean fungus to SWD.
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Affiliation(s)
- Paul G. Becher
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053 Alnarp, Sweden
| | - Rasmus E. Jensen
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
- Section for Entomology and Plant Pathology, Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Myrsini E. Natsopoulou
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
| | - Vasiliki Verschut
- Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053 Alnarp, Sweden
| | - Henrik H. De Fine Licht
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
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Mfuti DK, Subramanian S, van Tol RWHM, Wiegers GL, de Kogel WJ, Niassy S, du Plessis H, Ekesi S, Maniania NK. Spatial separation of semiochemical Lurem-TR and entomopathogenic fungi to enhance their compatibility and infectivity in an autoinoculation system for thrips management. PEST MANAGEMENT SCIENCE 2016; 72:131-139. [PMID: 25643946 PMCID: PMC5024074 DOI: 10.1002/ps.3979] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 12/08/2014] [Accepted: 01/17/2015] [Indexed: 05/29/2023]
Abstract
BACKGROUND The effect of spatial separation of the semiochemical Lurem-TR, which has been found to inhibit conidia of entomopathogenic fungi when put together, on the persistence of conidia of Metarhizium brunneum and M. anisopliae was evaluated in the greenhouse and field in order to develop an autodissemination strategy for the management of Megalurothrips sjostedti on cowpea crop. Influence of spatial separation of the semiochemical on thrips attraction and conidial acquisition by thrips from the autoinoculation device was also investigated in the field. RESULTS Persistence of conidia of M. brunneum and M. anisopliae increased with distance of separation of Lurem-TR. Direct exposure of fungus without separation from Lurem-TR recorded the lowest conidial germination as compared with the other treatments. Attraction of thrips to the device also varied significantly according to distance between device and semiochemical, with a higher number of thrips attracted when Lurem-TR was placed in a container below the device and at 10 cm distance. There was no significant difference in conidial acquisition between spatial separation treatments of conidia and Lurem-TR. Attraction of other insect pests to the device did not significantly vary between treatments. Positive correlations were found between conidial acquisition and thrips attraction. CONCLUSION This study suggests that spatial separation of fungal conidia from Lurem-TR in an autoinoculation device could provide a low-cost strategy for effective management of thrips in grain legume cropping systems.
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Affiliation(s)
- David K Mfuti
- International Centre of Insect Physiology and EcologyNairobiKenya
- Unit for Environmental Sciences and ManagementNorth‐West UniversityPotchefstroomSouth Africa
| | | | | | | | | | - Saliou Niassy
- International Centre of Insect Physiology and EcologyNairobiKenya
| | - Hannalene du Plessis
- Unit for Environmental Sciences and ManagementNorth‐West UniversityPotchefstroomSouth Africa
| | - Sunday Ekesi
- International Centre of Insect Physiology and EcologyNairobiKenya
| | - Nguya K Maniania
- International Centre of Insect Physiology and EcologyNairobiKenya
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Lacey L, Grzywacz D, Shapiro-Ilan D, Frutos R, Brownbridge M, Goettel M. Insect pathogens as biological control agents: Back to the future. J Invertebr Pathol 2015. [DOI: 10.1016/j.jip.2015.07.009] [Citation(s) in RCA: 545] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Colonization by arbuscular mycorrhizal and endophytic fungi enhanced terpene production in tomato plants and their defense against a herbivorous insect. Symbiosis 2015. [DOI: 10.1007/s13199-015-0319-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Effects of endophyte colonization of Vicia faba (Fabaceae) plants on the life-history of leafminer parasitoids Phaedrotoma scabriventris (hymenoptera: braconidae) and Diglyphus isaea (hymenoptera: eulophidae). PLoS One 2014; 9:e109965. [PMID: 25338084 PMCID: PMC4206285 DOI: 10.1371/journal.pone.0109965] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 09/10/2014] [Indexed: 12/02/2022] Open
Abstract
Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2nd and 3rd instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression.
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Akutse K, Maniania N, Fiaboe K, Van den Berg J, Ekesi S. Endophytic colonization of Vicia faba and Phaseolus vulgaris (Fabaceae) by fungal pathogens and their effects on the life-history parameters of Liriomyza huidobrensis (Diptera: Agromyzidae). FUNGAL ECOL 2013. [DOI: 10.1016/j.funeco.2013.01.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Use of Metarhizium anisopliae chitinase genes for genotyping and virulence characterization. BIOMED RESEARCH INTERNATIONAL 2013; 2013:465213. [PMID: 23936804 PMCID: PMC3722975 DOI: 10.1155/2013/465213] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/07/2013] [Accepted: 06/13/2013] [Indexed: 12/31/2022]
Abstract
Virulence is the primary factor used for selection of entomopathogenic fungi (EPF) for development as biopesticides. To understand the genetic mechanisms underlying differences in virulence of fungal isolates on various arthropod pests, we compared the chitinase genes, chi2 and chi4, of 8 isolates of Metarhizium anisopliae. The clustering of the isolates showed various groups depending on their virulence. However, the analysis of their chitinase DNA sequences chi2 and chi4 did not reveal major divergences. Although their protein translates have been implicated in fungal virulence, the predicted protein structure of chi2 was identical for all isolates. Despite the critical role of chitin digestion in fungal infection, we conclude that chi2 and chi4 genes cannot serve as molecular markers to characterize observed variations in virulence among M. anisopliae isolates as previously suggested. Nevertheless, processes controlling the efficient upregulation of chitinase expression might be responsible for different virulence characteristics. Further studies using comparative “in vitro” chitin digestion techniques would be more appropriate to compare the quality and the quantity of chitinase production between fungal isolates.
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Examining the “evolution of increased competitive ability” hypothesis in response to parasites and pathogens in the invasive paper wasp Polistes dominula. Naturwissenschaften 2013; 100:219-28. [DOI: 10.1007/s00114-013-1014-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 01/08/2013] [Accepted: 01/09/2013] [Indexed: 11/25/2022]
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Scientific Opinion on the risks to plant health posed by Liriomyza huidobrensis (Blanchard) and Liriomyza trifolii (Burgess) in the EU territory, with the identification and evaluation of risk reduction options. EFSA J 2012. [DOI: 10.2903/j.efsa.2012.3028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Niassy S, Maniania NK, Subramanian S, Gitonga LM, Mburu DM, Masiga D, Ekesi S. Selection of promising fungal biological control agent of the western flower thrips Frankliniella occidentalis (Pergande). Lett Appl Microbiol 2012; 54:487-93. [PMID: 22429122 DOI: 10.1111/j.1472-765x.2012.03241.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Larval stages of Frankliniella occidentalis are known to be refractory to fungal infection compared with the adult stage. The objective of this study was to identify promising fungal isolate(s) for the control of larval stages of F. occidentalis. METHODS AND RESULTS Ten isolates of Metarhizium anisopliae and eight of Beauveria bassiana were screened for virulence against second-instar larvae of F. occidentalis. Conidial production and genetic polymorphism were also investigated. Metarhizium anisopliae isolates ICIPE 7, ICIPE 20, ICIPE 69 and ICIPE 665 had the shortest LT(50) values of 8.0-8.9 days. ICIPE 69, ICIPE 7 and ICIPE 20 had the lowest LC(50) values of 1.1 × 10(7), 2.0 × 10(7) and 3.0 × 10(7) conidia ml(-1), respectively. Metarhizium anisopliae isolate ICIPE 69 produced significantly more conidia than M. anisopliae isolates ICIPE 7 and ICIPE 20. Internally transcribed spacers sequences alignment showed differences in nucleotides composition, which can partly explain differences in virulence. CONCLUSION These results coupled with the previous ones on virulence and field efficacy against other species of thrips make M. anisopliae isolate ICIPE 69 a good candidate. SIGNIFICANCE AND IMPACT OF THE STUDY Metarhizium anisopliae isolate ICIPE 69 can be suggested for development as fungus-based biopesticide for thrips management.
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Affiliation(s)
- S Niassy
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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