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Title: Biological control of Armillaria root rot of Selected Indigenous Trees of Mau Forest Complex using Arbuscular Mycorrhizae Fungi and trichoderma species
Authors: Sitienei, Philip Cheruiyot
Keywords: Armillaria root rot
Issue Date: Jan-2015
Publisher: Egerton University
Abstract: Mau Forest Complex is of critical importance for sustaining current and future ecological, social and economic development in Kenya. Mau Forest Complex is highly degraded and tree planting has been highly advocated. However, there is a threat to establishment of the seedlings by Armillaria species. The aim of this study was to evaluate efficacy of biological control agents for integrated control of Armillaria root rot of selected indigenous trees of Mau Forest Complex. Two fungal biological control agents, Trichoderma species and mycorrhizae, were applied individually and in combination in laboratory-based research and green house conditions to test their efficacy in controlling Armillaria root rot. Microscopic analysis of the mycorrhizal status of the selected indigenous trees from Mau forest complex showed that all the 10 plant species were colonized by arbuscular mycorrhizae fungi. AMF spores were obtained from all rhizosphere soil samples, where low density of AMF spores was generally observed. Visual observation of dual cultured plates showed antagonistic activity of Trichoderma species towards Armillaria species and an inhibition zone was observed at the margin between the antagonist and the pathogen. These initial results indicated that the strain of Trichoderma species can be used as a biocontrol agent against the tested Armillaria species. Dual inoculation of T. asperellum and arbuscular mycorrhizal fungi significantly reduced the level of root colonisation by arbuscular mycorrhizal fungi while co-inoculation with arbuscular mycorrhizal fungi and T. harzianum produced a higher percentage of colonization than any other treatment. Ecological measures of diversity used to describe the structure of Arbuscular mycorrhizae fungi (AMF) communities included spore density, species richness, relative abundance, isolation frequency, Shannon–Wiener index of diversity, evenness, Simpson’s index of dominance, and Sorenson’s coefficient. Differences in spore density and species richness between sites with plant species were tested using one-way ANOVA. The Pearson correlation coefficient was employed to determine the relationships between spore density and species richness, relative abundance and isolation frequency. Correlation analyses with Pearson’s correlation coefficients were used to determine if a relationship existed between soil microbial parameters and soil chemical properties. All data was subjected to analysis of variances (ANOVA) using Gen stat and treatment means were compared by Fisher’s least significant difference (LSD) test. The selected indigenous trees roots are colonized by AMF. The abundance of arbuscules and vesicle within the roots of these plants suggests that AMF have important influence on plant communities.
Appears in Collections:Faculty of Agriculture

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