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Miranda-Calixto A, Loera-Corral O, López-Pérez M, Figueroa-Martínez F. Improvement of Akanthomyces lecanii resistance to tebuconazole through UV-C radiation and selective pressure on microbial evolution and growth arenas. J Invertebr Pathol 2023; 198:107914. [PMID: 36958641 DOI: 10.1016/j.jip.2023.107914] [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: 08/12/2022] [Revised: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 03/25/2023]
Abstract
Tebuconazole (TEB) is a fungicide widely used in agriculture; however, its constant application has increased the emergence of resistant plant pathogenic fungal strains and reduced the effectiveness of fungi as biological control agents; for instance, the entomopathogenic and hyperparasitic fungus Akanthomyces lecanii, suitable for simultaneous biological control of insect pest and plant pathogenic fungi, is highly sensitive to fungicides. We carried out the induction of resistance to TEB in two wild type strains of A. lecanii by UV radiation and selective pressure in increasing fungicide gradients using a modified Microbial Evolution and Growth Arena (MEGA), to produce A. lecanii strains that can be used as biological control agent in the presence of tebuconazole. Nine UV-induced and three naturally adapted A. lecanii strains were resistant to TEB at the agriculturally recommended dose, and three irradiated strains were resistant to TEB concentration ten times higher; moreover, growth, sporulation rates, production of hydrolytic enzymes, and virulence against the hemipteran Coccus viridis, a major pest of coffee crops, were not affected in the TEB-resistant strains. These A. lecanii TEB-resistant strains would have a greater opportunity to develop and to establish themselves in fields where the fungicide is present and can be used in a combined biological-chemical strategy to improve insect and plant pathogenic fungal control in agriculture. Also, the selective pressure through modified MEGA plate methodology can be used for the adaptation of entomopathogenic filamentous fungi to withstand other chemical or abiotic stresses that limits its effectiveness for pest control.
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Affiliation(s)
- Arturo Miranda-Calixto
- Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Biotecnología, San Rafael Atlixco 186, Col. Vicentina, C. P. 09340 CDMX, Mexico
| | - Octavio Loera-Corral
- Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Biotecnología, San Rafael Atlixco 186, Col. Vicentina, C. P. 09340 CDMX, Mexico
| | - Marcos López-Pérez
- Universidad Autónoma Metropolitana-Lerma Departamento de Ciencias Ambientales, Av. de las Garzas 10, El panteón, C. P. 52005 Lerma de Villada, Mexico
| | - Francisco Figueroa-Martínez
- CONACyT Research Fellow - Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, C. P. 09340 CDMX, Mexico.
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Collier R, Mazzi D, Folkedal Schjøll A, Schorpp Q, Thöming G, Johansen TJ, Meadow R, Meyling NV, Cortesero AM, Vogler U, Gaffney MT, Hommes M. The Potential for Decision Support Tools to Improve the Management of Root-Feeding Fly Pests of Vegetables in Western Europe. INSECTS 2020; 11:insects11060369. [PMID: 32545796 PMCID: PMC7349907 DOI: 10.3390/insects11060369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/10/2020] [Accepted: 06/10/2020] [Indexed: 11/16/2022]
Abstract
Several important vegetable crops grown outdoors in temperate climates in Europe can be damaged by the root-feeding larvae of Diptera (Delia radicum, Delia floralis, Chamaepsila rosae, Delia platura, Delia florilega, Delia antiqua). Knowledge of pest insect phenology is a key component of any Integrated Pest Management (IPM) strategy, and this review considers the methods used to monitor and forecast the occurrence of root-feeding flies as a basis for decision-making by growers and the ways that such information can be applied. It has highlighted some current management approaches where such information is very useful for decision support, for example, the management of C. rosae with insecticidal sprays and the management of all of these pests using crop covers. There are other approaches, particularly those that need to be applied at sowing or transplanting, where knowledge of pest phenology and abundance is less necessary. Going forward, it is likely that the number of insecticidal control options available to European vegetable growers will diminish and they will need to move from a strategy which often involves using a single ‘silver bullet’ to a combination of approaches/tools with partial effects (applied within an IPM framework). For the less-effective, combined methods, accurate information about pest phenology and abundance and reliable decision support are likely to be extremely important.
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Affiliation(s)
- Rosemary Collier
- Warwick Crop Centre, School of Life Sciences, University of Warwick, Wellesbourne, Warwick CV35 9EF, UK
- Correspondence:
| | - Dominique Mazzi
- Agroscope, Research Division Plant Protection, Müller-Thurgau-Strasse 29, 8820 Wädenswil, Switzerland;
| | - Annette Folkedal Schjøll
- Norwegian Institute of Bioeconomy Research (NIBIO), Division of Biotechnology and Plant Health, P.O. Box 115, NO-1431 Ås, Norway; (A.F.S.); (G.T.); (T.J.J.)
| | - Quentin Schorpp
- Julius Kühn Institute (JKI), Institute for Plant Protection in Horticulture and Forests, Messeweg 11-12, D-38104 Braunschweig, Germany; (Q.S.); (U.V.); (M.H.)
| | - Gunda Thöming
- Norwegian Institute of Bioeconomy Research (NIBIO), Division of Biotechnology and Plant Health, P.O. Box 115, NO-1431 Ås, Norway; (A.F.S.); (G.T.); (T.J.J.)
| | - Tor J. Johansen
- Norwegian Institute of Bioeconomy Research (NIBIO), Division of Biotechnology and Plant Health, P.O. Box 115, NO-1431 Ås, Norway; (A.F.S.); (G.T.); (T.J.J.)
| | - Richard Meadow
- Department of Plant Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway;
| | - Nicolai V. Meyling
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark;
| | | | - Ute Vogler
- Julius Kühn Institute (JKI), Institute for Plant Protection in Horticulture and Forests, Messeweg 11-12, D-38104 Braunschweig, Germany; (Q.S.); (U.V.); (M.H.)
| | - Michael T. Gaffney
- Horticultural Development Department, Teagasc, Ashtown, D15DY05 Dublin 15, Ireland;
| | - Martin Hommes
- Julius Kühn Institute (JKI), Institute for Plant Protection in Horticulture and Forests, Messeweg 11-12, D-38104 Braunschweig, Germany; (Q.S.); (U.V.); (M.H.)
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Razinger J, Lutz M, Grunder J, Urek G. Laboratory Investigation of Cauliflower-Fungus-Insect Interactions for Cabbage Maggot Control. JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:2578-2584. [PMID: 30107578 DOI: 10.1093/jee/toy228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The cabbage maggot (also known as cabbage root fly [CRF]; Delia radicum L.) is a serious pest of brassicas. The pest's soil-dwelling larvae are especially damaging to young brassica transplants. In light of toxic soil insecticide phase-out novel biocontrol management solutions are sought for. Our research is focused on the development of a biological control strategy involving cauliflower plantlet inoculation with insect pathogenic fungi. This article presents the results of a laboratory investigation of cauliflower × microbe × CRF interactions. Seven isolates of fungi (entomopathogenic and rhizosphere-competent fungi and soil saprotrophs) were tested for their pathogenicity to CRF and their effects on cauliflower plantlets. The laboratory experiments were performed in sterilized substrate. Several strains significantly increased CRF mortality, some at par with a commercial bioinsecticide based on B. bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae). All strains colonized the rhizoplane, however to varying extent. Some isolates were also reisolated from within healthy plant tissues and thus identified as endophytes. The method of applying conidia had a significant effect on survival and weight of seedlings and rhizoplane and endophytic colonization rates. Two Metarhizium brunneum Petsch (Hypocreales: Clavicipitaceae) isolates exhibited plant growth promotion effects when ungerminated seeds were coated with conidia. The ecological implications of plant × microbe × pest interactions and options for improving the effectiveness of a fungal-based biological CRF management strategy are discussed.
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Affiliation(s)
- Jaka Razinger
- Plant Protection Department, Agricultural Institute of Slovenia, Hacquetova ulica, Ljubljana, SI, Slovenia
| | - Matthias Lutz
- Agroscope, Competence Division Plants and Plant Products, Schloss, Wädenswil, CH, Switzerland
| | - Jürg Grunder
- School of Life Sciences and Facility Management, Zurich University of Applied Sciences, Campus Grueental, Wädenswil, CH, Switzerland
| | - Gregor Urek
- Plant Protection Department, Agricultural Institute of Slovenia, Hacquetova ulica, Ljubljana, SI, Slovenia
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Razinger J, Žerjav M, Zemljič-Urbančič M, Modic Š, Lutz M, Schroers HJ, Grunder J, Fellous S, Urek G. Comparison of cauliflower-insect-fungus interactions and pesticides for cabbage root fly control. INSECT SCIENCE 2017; 24:1057-1064. [PMID: 28856839 DOI: 10.1111/1744-7917.12534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 08/21/2017] [Accepted: 08/26/2017] [Indexed: 06/07/2023]
Abstract
Cabbage root fly (Delia radicum L.) control represents a major challenge in brassica production, therefore different management strategies for its control were tested in conventionally managed open field cauliflower production. Strategies included treatments with low-risk methods such as nitrogen lime, the insecticide spinosad and the Beauveria bassiana ATCC 74040-based biopesticide Naturalis. Their effects were compared with treatments based on nonformulated fungal species Metarhizium brunneum, B. bassiana, Clonostachys solani, Trichoderma atroviride, T. koningiopsis, and T. gamsii and commercial insecticides λ-cyhalothrin and thiamethoxam. Spinosad and thiamethoxam were pipetted to individual plants before transplanting; λ-cyhalothrin was sprayed after transplanting; nitrogen lime was applied at first hoeing. Nonformulated fungi were delivered onto cauliflower plantlets' roots as a single pretransplantation inoculation. The cabbage root fly population dynamics exhibited a strong spatiotemporal variation. The lowest number of cabbage root fly pupae recovered from cauliflower roots in the field experiments was recorded in plants treated with spinosad (significant reduction), followed by Naturalis and one of the tested M. brunneum strains (nonsignificant reduction). Significantly more pupae were counted in the nitrogen lime treatment. The field experiments showed that a single drench of cauliflower plantlets with spinosad offered consistent and enduring cabbage root fly control. Naturalis and nonformulated fungal isolates did not decrease cabbage root fly pressure significantly, apparently due to lack of statistical power. The implications of the substantial intra- and inter-annual pest pressure variation and the benefits of using single plant treatments are discussed, and recommendations for improvement of rhizosphere-competence utilizing biological control strategies provided.
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Affiliation(s)
- Jaka Razinger
- Agricultural Institute of Slovenia, Plant Protection Department, Ljubljana, Slovenia
| | - Metka Žerjav
- Agricultural Institute of Slovenia, Plant Protection Department, Ljubljana, Slovenia
| | - Meta Zemljič-Urbančič
- Agricultural Institute of Slovenia, Plant Protection Department, Ljubljana, Slovenia
| | - Špela Modic
- Agricultural Institute of Slovenia, Plant Protection Department, Ljubljana, Slovenia
| | - Matthias Lutz
- Agroscope, Institut für Pflanzenbauwissenschaften, Waedenswil, Switzerland
| | - Hans-Josef Schroers
- Agricultural Institute of Slovenia, Plant Protection Department, Ljubljana, Slovenia
| | - Jürg Grunder
- Zurich University of Applied Sciences, School of Life Sciences and Facility Management, Campus Grueental, Waedenswil, Switzerland
| | - Simon Fellous
- INRA, Center for the Biology and Management of Populations (CBGP), UMR, Montpellier, France
| | - Gregor Urek
- Agricultural Institute of Slovenia, Plant Protection Department, Ljubljana, Slovenia
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Joseph SV, Godfrey LD, Bettiga C. Influence of Interval Between Postharvest Lettuce Residue Management and Subsequent Seeding of Broccoli on Cabbage Maggot (Diptera: Anthomyiidae) Infestation on Broccoli. JOURNAL OF ECONOMIC ENTOMOLOGY 2017; 110:2172-2179. [PMID: 28981649 DOI: 10.1093/jee/tox196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Indexed: 06/07/2023]
Abstract
Larval stages of cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae), attack the roots of Brassica crops and cause severe economic damage. In the Salinas Valley of California, Brassica crops are often planted after successive lettuce (Lactuca sativa L.) crops. The interval between postharvest soil incorporation of lettuce residue and the subsequent Brassica crop can be as short as 7 d, which could influence D. radicum infestation on broccoli (Brassica oleracea var. italica Plenck). In 2014 and 2015, the effect of intervals between crops (IBC) on D. radicum infestation was evaluated. The treatments were 7, 20, 33, and 48 d IBC, and NL (no lettuce), 7, 21, 36, and 49 d IBC in 2014 and 2015, respectively. Insect counts and feeding damage on broccoli was assessed during 3-6 wk after planting. Adult Delia fly captures were significantly greater at 7 d than 36-49 d IBC in both years. In both years, D. radicum eggs collected were significantly greater at 7 d than at 33 d or 36 d IBC plots. Larvae collected were significantly greater at 7 d IBC than all other treatments in 2014, but not in 2015. Similarly, severity of feeding injury was significantly greater in 7 d than 33 d or 48 d IBC in 2014, but not in 2015. In 2015, broccoli with no prior lettuce had significantly lower Delia flies and D. radicum egg densities than 7 d or 21 d IBC. The implication of these results as a cultural control tactic for D. radicum infestation is discussed.
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Affiliation(s)
- Shimat V Joseph
- University of California Cooperative Extension, 1432 Abbott St., Salinas, CA 93901
| | - Larry D Godfrey
- Department of Entomology and Nematology, University of California, Davis, CA 95616
| | - Christopher Bettiga
- University of California Cooperative Extension, 1432 Abbott St., Salinas, CA 93901
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Zhang H, Wu S, Xing Z, Wang X, Lei Z. Bioassay and Scanning Electron Microscopic Observations Reveal High Virulence of Entomopathogenic Fungus, Beauveria bassiana, on the Onion Maggot (Diptera: Anthomyiidae) Adults. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:2309-2316. [PMID: 27986935 DOI: 10.1093/jee/tow235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/22/2016] [Indexed: 06/06/2023]
Abstract
When flies were dipped in 1 × 108 conidia/ml conidia suspensions and then kept in the incubator (22 ± 1 °C, 70 ± 5% RH), scanning electron microscope observations revealed that, at 2 h, the majority of adhering Beauveria bassiana conidia were attached to either the wing surface or the interstitial area between the macrochaetae on the thorax and abdomen of the onion maggot adults. Germ tubes were being produced and had oriented toward the cuticle by 18 h. Penetration of the insect cuticle had occurred by 36 h, and by 48 h, germ tubes had completely penetrated the cuticle. Fungal mycelia had emerged from the insect body and were proliferating after 72 h. The superficial area and structure of the wings and macrochaetae may facilitate the attachment of conidia and enable effective penetration. The susceptibility of adults to 12 isolates, at a concentration of 1 × 107 conidia/ml, was tested in laboratory experiments. Eight of the more potent strains caused in excess of 85% adult mortality 8 d post inoculation, while the median lethal time (LT50) of these strains was <6 d. The virulence of the more effective strains was further tested, and the median lethal concentrations (LC50) were calculated by exposing adults to doses ranging from 103-107 conidia/ml. The lowest LC50 value, found in the isolate XJWLMQ-32, for the adults was 3.87 × 103 conidia/ml. These results demonstrate that some B. bassiana strains are highly virulent to onion maggot adults and should be considered as potential biocontrol agents against the adult flies.
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Affiliation(s)
- Hui Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China (; ; ; )
| | - Shengyong Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China (; ; ; )
| | - Zhenlong Xing
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China (; ; ; )
| | - Xiaoqing Wang
- Plant Protection Station of Beijing, Beijing 100029, China
| | - Zhongren Lei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China (; ; ; )
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fuzhou 350002, China, and
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7
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Kergunteuil A, Bakhtiari M, Formenti L, Xiao Z, Defossez E, Rasmann S. Biological Control beneath the Feet: A Review of Crop Protection against Insect Root Herbivores. INSECTS 2016; 7:E70. [PMID: 27916820 PMCID: PMC5198218 DOI: 10.3390/insects7040070] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 12/15/2022]
Abstract
Sustainable agriculture is certainly one of the most important challenges at present, considering both human population demography and evidence showing that crop productivity based on chemical control is plateauing. While the environmental and health threats of conventional agriculture are increasing, ecological research is offering promising solutions for crop protection against herbivore pests. While most research has focused on aboveground systems, several major crop pests are uniquely feeding on roots. We here aim at documenting the current and potential use of several biological control agents, including micro-organisms (viruses, bacteria, fungi, and nematodes) and invertebrates included among the macrofauna of soils (arthropods and annelids) that are used against root herbivores. In addition, we discuss the synergistic action of different bio-control agents when co-inoculated in soil and how the induction and priming of plant chemical defense could be synergized with the use of the bio-control agents described above to optimize root pest control. Finally, we highlight the gaps in the research for optimizing a more sustainable management of root pests.
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Affiliation(s)
- Alan Kergunteuil
- Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
| | - Moe Bakhtiari
- Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
| | - Ludovico Formenti
- Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
| | - Zhenggao Xiao
- Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
| | - Emmanuel Defossez
- Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
| | - Sergio Rasmann
- Functional Ecology Laboratory, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
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8
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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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Cotes B, Rännbäck LM, Björkman M, Norli HR, Meyling NV, Rämert B, Anderson P. Habitat selection of a parasitoid mediated by volatiles informing on host and intraguild predator densities. Oecologia 2015; 179:151-62. [PMID: 25943193 PMCID: PMC4553151 DOI: 10.1007/s00442-015-3326-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/16/2015] [Indexed: 11/30/2022]
Abstract
To locate and evaluate host patches before oviposition, parasitoids of herbivorous insects utilize plant volatiles and host-derived cues, but also evaluate predator-derived infochemicals to reduce predation risks. When foraging in host habitats infested with entomopathogenic fungi that can infect both a parasitoid and its host, parasitoids may reduce the risk of intraguild predation (IGP) by avoiding such patches. In this study, we examined whether the presence of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana in soil habitats of a root herbivore, Delia radicum, affects the behavior of Trybliographa rapae, a parasitoid of D. radicum. Olfactometer bioassays revealed that T. rapae avoided fungal infested host habitats and that this was dependent on fungal species and density. In particular, the parasitoid avoided habitats with high densities of the more virulent fungus, M. brunneum. In addition, host density was found to be important for the attraction of T. rapae. Volatiles collected from host habitats revealed different compound profiles depending on fungal presence and density, which could explain the behavior of T. rapae. We conclude that T. rapae females may use volatile compounds to locate high densities of prey, but also compounds related to fungal presence to reduce the risk of IGP towards themselves and their offspring.
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Affiliation(s)
- Belén Cotes
- Department of Plant Protection Biology, Integrated Plant Protection, Swedish University of Agricultural Sciences, P.O. Box 102, Växtskyddsvägen 3, Alnarp, SE-230 53, Sweden,
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10
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Myrand V, Buffet JP, Guertin C. Susceptibility of Cabbage Maggot Larvae (Diptera: Anthomyiidae) to Hypocreales Entomopathogenic Fungi. JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:34-44. [PMID: 26470101 DOI: 10.1093/jee/tou019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 10/20/2014] [Indexed: 06/05/2023]
Abstract
The pathogenicity of six Metarhizium spp., four Beauveria bassiana (Balsamo) Vuillemin, and four Tolypocladium cylindrosporum Gams (Ascomycota: Hypocreales) fungal pathogens exposed to third-instar Delia radicum L. was evaluated in laboratory bioassays. The presence of intra- and intergeneric variations concerning the pathogenicity of the isolates was investigated. Results show that all Metarhizium spp. and T. cylindrosporum isolates caused a noteworthy mortality to the third instar and consequently reduced adult eclosion. The well-known standard, F52 strain (identified as Metarhizium brunneum), resulted in up to 79% reduction in D. radicum eclosion. The other Metarhizium isolates including UAMH 9197 (Metarhizium anisopliae) and UAMH 2801 (M. brunneum), as well as T. cylindrosporum DAOM 167325 and DAOM 183952, produced a mean eclosion reduction of >50%. While the pathogenicity of Metarhizium spp. and T. cylindrosporum is similar, the B. bassiana isolates are undoubtedly less pathogenic. Based on the results obtained with the selected isolates, no intrageneric differences relative to the pathogenicity of the isolates appeared to be present. Globally, this study deepened the knowledge about D. radicum susceptibility toward Hypocreales entomopathogenic fungi, chiefly T. cylindrosporum. The implications of this study regarding the development of a biological control agent are discussed.
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Affiliation(s)
- V Myrand
- INRS-Institut Armand Frappier, Laval, QC, Canada H7V1B7
| | - J P Buffet
- INRS-Institut Armand Frappier, Laval, QC, Canada H7V1B7
| | - C Guertin
- INRS-Institut Armand Frappier, Laval, QC, Canada H7V1B7
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11
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Rännbäck LM, Cotes B, Anderson P, Rämert B, Meyling NV. Mortality risk from entomopathogenic fungi affects oviposition behavior in the parasitoid wasp Trybliographa rapae. J Invertebr Pathol 2014; 124:78-86. [PMID: 25446037 DOI: 10.1016/j.jip.2014.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/29/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
Biological control of pests in agroecosystems could be enhanced by combining multiple natural enemies. However, this approach might also compromise the control efficacy through intraguild predation (IGP) among the natural enemies. Parasitoids may be able to avoid the risk of unidirectional IGP posed by entomopathogenic fungi through selective oviposition behavior during host foraging. Trybliographa rapae is a larval parasitoid of the cabbage root fly, Delia radicum. Here we evaluated the susceptibility of D. radicum and T. rapae to two species of generalist entomopathogenic fungi, Metarhizium brunneum isolate KVL 04-57 and Beauveria bassiana isolate KVL 03-90. Furthermore, T. rapae oviposition behavior was assessed in the presence of these entomopathogenic fungi either as infected hosts or as infective propagules in the environment. Both fungi were pathogenic to D. radicum larvae and T. rapae adults, but with variable virulence. When host patches were inoculated with M. brunneum conidia in a no-choice situation, more eggs were laid by T. rapae in hosts of those patches compared to control and B. bassiana treated patches. Females that later succumbed to mycosis from either fungus laid significantly more eggs than non-mycosed females, indicating that resources were allocated to increased oviposition due to perceived decreased life expectancy. When presented with a choice between healthy and fungal infected hosts, T. rapae females laid more eggs in healthy larvae than in M. brunneum infected larvae. This was less pronounced for B. bassiana. Based on our results we propose that T. rapae can perceive and react towards IGP risk posed by M. brunneum but not B. bassiana to the foraging female herself and her offspring. Thus, M. brunneum has the potential to be used for biological control against D. radicum with a limited risk to T. rapae populations.
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Affiliation(s)
- Linda-Marie Rännbäck
- Department of Plant Protection Biology, Integrated Plant Protection, Swedish University of Agricultural Sciences, Växtskyddsvägen 3, P.O. Box 102, SE-230 53 Alnarp, Sweden.
| | - Belen Cotes
- Department of Plant Protection Biology, Integrated Plant Protection, Swedish University of Agricultural Sciences, Växtskyddsvägen 3, P.O. Box 102, SE-230 53 Alnarp, Sweden
| | - Peter Anderson
- Department of Plant Protection Biology, Chemical Ecology, Swedish University of Agricultural Sciences, Växtskyddsvägen 3, P.O. Box 102, SE-230 53 Alnarp, Sweden
| | - Birgitta Rämert
- Department of Plant Protection Biology, Integrated Plant Protection, Swedish University of Agricultural Sciences, Växtskyddsvägen 3, P.O. Box 102, SE-230 53 Alnarp, Sweden
| | - Nicolai V Meyling
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
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