Rootzone mixture affects the population of root-invading fungi in zoysiagrass

摘要

Rootzone mixture is well known to affect the root growth of turfgrass below ground and turf quality, but limited information is available on the effect of the mixture on the population of root-invading fungi. The main objective of this study was to determine the population of root-invading fungi in zoysiagrass (Zoysia japonica) grown in five different rootzone mixtures in Guangzhou, China. Pathogenicity of six fungal isolates was tested by seed inoculation. Biological potential of Trichoderma isolate was evaluated against pathogenic fungi in dual culture technique. A total of 15 fungi were isolated from zoysiagrass roots. The main four species of fungi isolated from all the rootzones were Aspergillus nige, Fusarium oxysporum, Nigrosporasp. and Rhizoctoniasp. The total percentage of root segments yielding fungal colonies was highest in Z (85% sand + 15% zeolite) and M (85% sand + 7.5% peat + 7.5% zeolite) rootzone. Seedlings were easily infected by all the tested fungal isolates and the symptoms of disease were common. The pathogenic fungi significantly decreased the seed germination rate and seedling dry matter. The Trichoderma isolate had marked statistical inhibitory effects on mycelial growth of the pathogens compared with the control. Fusarium oxysporumwas most susceptible to the Trichoderma. On the basis of our results for root-invading fungi investigation from zoysiagrass roots, the usage of zeolite in rootzone construction of turf establishment should be considered carefully in the future.