Abstract
This thesis investigates the natural occurrence of the fungal genus Metarhizium in association with crop-roots in Denmark, and advances the current understanding of how these fungi interact with other root-associating organisms when applied as a biological control agent.
Insect-pest management is an increasingly important area of research. Efforts to maximize agricultural output are significantly dependent on reliable means for pest suppression. Biological control, or the use of living organisms to suppress a pest population, is a leading alternative to traditional chemical-based pesticides for crop protection. The fungal genus Metarhizium is one of the most intensely researched groups of entomopathogenic fungi and several isolates have been successfully employed as biopesticides for crop protection; however, inconsistent field reliability has limited wider implementation. Research emphasizing the natural ecology of Metarhizium as well as it’s interactions with other organism would significantly help to reduce unpredictability in the field. This thesis advances our understanding of Metarhizium ecology in several key aspects, including:
Investigations of Metarhizium interactions with plants and other plant-associated microorganisms yielded several interesting observations, namely: Metarhizium was dispersed through soil with roots after seed inoculations; Metarhizium maintained its insect pathogenicity while interacting with plants; Metarhizium did not interfere with the ability of the mycoparasitic fungus Clonostachys roseas to control Fusarium culmorum disease in wheat; and a significant level of insect mortality was observed in insects feeding on roots from inoculated seed – even when Metarhizium was applied jointly with C. rosea.
Furthermore, M. flavoviride, a less frequently studied species of Metarhizium, was found to be highly prevalent in Danish agricultural fields and in the nearby natural grasses that were included in this study. Intraspecies diversity among the M. flavoviride isolates was analyzed using unspecific markers, this characterization revealed a high level of variability with in the species.
The results of these studies further clarify the important role Metarhizium spp. play in the natural environment and highlight their vast potential to be implemented as biological control agents of important pest insects.
Insect-pest management is an increasingly important area of research. Efforts to maximize agricultural output are significantly dependent on reliable means for pest suppression. Biological control, or the use of living organisms to suppress a pest population, is a leading alternative to traditional chemical-based pesticides for crop protection. The fungal genus Metarhizium is one of the most intensely researched groups of entomopathogenic fungi and several isolates have been successfully employed as biopesticides for crop protection; however, inconsistent field reliability has limited wider implementation. Research emphasizing the natural ecology of Metarhizium as well as it’s interactions with other organism would significantly help to reduce unpredictability in the field. This thesis advances our understanding of Metarhizium ecology in several key aspects, including:
Investigations of Metarhizium interactions with plants and other plant-associated microorganisms yielded several interesting observations, namely: Metarhizium was dispersed through soil with roots after seed inoculations; Metarhizium maintained its insect pathogenicity while interacting with plants; Metarhizium did not interfere with the ability of the mycoparasitic fungus Clonostachys roseas to control Fusarium culmorum disease in wheat; and a significant level of insect mortality was observed in insects feeding on roots from inoculated seed – even when Metarhizium was applied jointly with C. rosea.
Furthermore, M. flavoviride, a less frequently studied species of Metarhizium, was found to be highly prevalent in Danish agricultural fields and in the nearby natural grasses that were included in this study. Intraspecies diversity among the M. flavoviride isolates was analyzed using unspecific markers, this characterization revealed a high level of variability with in the species.
The results of these studies further clarify the important role Metarhizium spp. play in the natural environment and highlight their vast potential to be implemented as biological control agents of important pest insects.
| Originalsprog | Engelsk |
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| Forlag | Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen |
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| Antal sider | 109 |
| Status | Udgivet - 2015 |