Trichoderma spp is a widespread plant disease biocontrol fungus in soil. Doraagri test on Trichoderma asperellum isolated from lawn, the results showed that Trichoderma asperellum has the characteristics of high temperature resistance and high salinity, can inhibit the growth of pathogenic bacteria through various ways, and can significantly reduce the occurrence of turfgrass brown spot, which has great potential in the field of turfgrass disease biocontrol.
Disease management is the key of lawn maintenance management. There are many kinds of lawn diseases, among which brown spot is a high incidence disease of cool-season lawn. Turfgrass brown spot is a very serious worldwide turf disease, mainly caused by Rhizoctonia solani.
Rhizoctonia solani has a wide range of hosts and can infect all turfgrass, with rapid infection and repeated onset. At present, the control of lawn diseases is still dominated by chemical control. The extensive use of fungicides will not only cause environmental pollution, but also easily make pathogenic bacteria resistant to drugs, thereby increasing the difficulty of disease control.
1. Environmental adaptability
Trichoderma asperellum can grow in the range of 15-45 ℃, but the optimum growth temperature is 25-35 ℃. Within this range, the strain of Trichoderma grows fast, and the medium can be completely covered within 3 days.
At 15°C, the growth of Trichoderma was inhibited, and only half of the medium was covered within 3 days. Trichoderma survived at 40 ℃ and 45 ℃, but only a small amount of mycelial growth was observed on the medium.
2. Antagonism against pathogenic bacteria
Doraagri co-cultured Trichoderma and Rhizoctonia solani for 3 days. The results showed that Trichoderma aculeatus had obvious inhibitory effect on Rhizoctonia solani, and the inhibition rate reached 57.8%.
Trichoderma asperellum exhibited a strong inhibitory effect on the growth of pathogenic bacteria and induced resistance of turfgrass to pathogenic infection. Secretion of antagonistic metabolites is an important way for trichoderma asperellum to antagonize pathogenic bacteria.
After 7 days of co-cultivation of Trichoderma and pathogenic bacteria, the hyphae of Rhizoctonia solani were all covered by Trichoderma, and the inhibition rate reached 100%.
Trichoderma asperellum can adapt to a wide range of environments, can withstand high temperature of 35 °C, and can grow normally at a NaCl concentration of 150 g·L-1 and a pH of 5 to 12.
It can significantly inhibit the growth of Rhizoctonia solani through steric competition and secretion of antagonistic metabolites. After inducing turfgrass by root irrigation with Trichoderma asperellum, the occurrence of brown spot and other diseases can be significantly reduced, so it has a good potential to be developed as a biocontrol agent for turfgrass diseases.