NGHIÊN CỨU VỀ MỘT SỐ ĐẶC ĐIỂM SINH HỌC NẤM PYTHIUM HELICOIDES GÂY BỆNH THỐI NÕN CÂY MẠCH MÔN VÀ BIỆN PHÁP PHÒNG TRỪ

Mondo grass (Ophiopogon Japonicus Wall) is an economical crop in some northern provinces of Vietnam. Researches in Vietnam and overseas showed that the most dangerous disease of mondo grass is the stem rot disease caused by Pythium spp.. In Vietnam, through the artificial disease infection and DNA analysis, we identified the fungus Pythium helicoides is the cause of the stem rot disease of mondo grass. Further research on the characteristics and control measures of Pythium helicoides showed that the fungus is best grown at the temperature of 26 - 30oC, pH at 5.0 - 7.5; the illumination time does not influence the fungal growth. Using the antagonistic fungi Trichoderma asperellum and Streptomyces misionensis, Streptomyces aureofaciens, Bacillus amyloliquefaciens can supress the growth of Pythium helicoides by above 80%. The fungicides Rhidomil MZ 72 WP 0,2% and Viben - C 50 BTN 0,2% can control Pythium helicoides at the high rate of above 90%.