Biological Control of Large Patch Disease and Pythium Blight Disease of Turfgrasses
Date Issued
2008
Date
2008
Author(s)
Chou, Yu-Wei
Abstract
Turf-ecosystem is very different from that of normal agriculture. Turf leaves, with high density, usually get wounded by cutting. The watering interval is very short for sport courts. These conditions faver the occurrence and dispersal of turf diseases. Among the turfgrass diseases, large patch(=brown patch) and Pythium blight, caused by Rhizoctonia solani and Pythium spp., respatively, are two major diseases around the world. The principal disease control method for turfgrasses is pesticide control, and it is associated with enviromental pollution, pesticide resistance, risk to beneficent organisms etc., in addition to the huge cost. Therefore, scientists have made great efforts in developing the biological control. There have been several successful examples of utilizing Trichoderma harzianum T1295-22 to suppress three diseases of temperate turfgrasses, which elong to C3 plants. However, there is still no biological contol method to control the diseases occuring on tropical turfgrasses, which belong to C4 plants. For this reason, this study is aimed for studying and developing the biological control methods for suppressing large patch and Pythium blight diseases of bermudagrass, zoysiagrass, and seashore paspalum by utilizing Trichoderma harzianum and Streptomyces sp. The dual culture experiments, with two biocontrol agents against two pathogens on PDA medium showed that both biocontrol agents are antagonistic to both two pathogens. Results of the pot experiments in the greenhouse, with both two biocontrol agents against both two pathogens showed that Trichoderma harzianum has better disease-suppression potential than Streptomyces sp. Application of the Trichoderma harzianum delayed the disease development for as long as 6 days, showing the same or even better disease-suppression efficacy than the fungicide azoxystrobin. Two field experiments were also conducted in the NTU Farm. The first was to apply the biocontrol agent in present turf to test the control efficacy of it. The second was to grow the new turfgrasses and apply the biocontrol agents simultaneously. In both experiments, Trichoderma harzianum exhibited good disease-control ability. In conclusion, Trichoderma harzianum is proven to have the potential to become a biocontrol agent to suppress the large patch and Pythium blight diseases of these three turfgrasses in Taiwan.
Subjects
large patch disease
Pythium blight disease
Trichoderma harzianum
Streptomyces sp
biological control
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