Identification,Biological Characteristics And Indoor Virulence Test For Pathogen Causing Strawberry Root Rot In Changli

With the increasing of strawberry root rot in Hebei Province in Changli,in the paper,the pathogen species of strawberry root rot in this area were identified,the biological characteristics of dominant pathogenic bacteria and their indoor toxicity determination were studied,based on the preliminary study of strawberry root rot,it was further applied to the actual production to solve the problem of farmers.By separating and purifying the pathogen of strawberry root,300 strains were divided into seven groups,and the highest separation frequency was between Fusarium Oxysporium and Phytophthora cactorum.The pathogenicfungi of Fusarium Oxysporium and Phytophthora cactorum were identified as strawberry root rot by Koch's law.In the study of the biological characteristics of pathogenic bacteria,the temperature range of mycelium growth of Fusarium oxysporum was 5~35 ?,less than 5 ? hyphae stopped growing,more than 35 ? hyphae geow slowly,and the optimum growth temperature of hyphae was 28 ?.The mycelial growth can grow normally between the ph value and the 3~11,and the Fusarium oxysporum was more suitable for the partial alkaline condition.Different illumination conditions had little influence on the growth of hyphae.Different carbon sources and nitrogen sources had different effects on the growth of hyphae,the most suitable carbon source was soluble starch and lactose,and the most suitable nitrogen source was yeast extract.The lethal temperature of conidia of Fusarium oxysporum was 50 ?.The temperature range of the fungus was 5~35 ?,exceeding the temperature range the hyphae almost ceased to grow,and 28 was the optimum temperature for ?the growth of the Phytophthora cactorum filaments.The PH value can grow normally between 3~10,the suitable acid-base condition was 5~8,so it was more favorable for mycelial growth under neutral condition.The different illumination conditions had no obvious influence on the growth of mold filaments,different carbon sources,nitrogen source on the mycelial effect of a greater difference,lactose than other carbon sources more suitable for mycelial growth,Phytophthora mildew silk in(NH4)2SO4 and urea conditions do not grow,under the same conditions,yeast paste and peptone were more suitable for mycelial growth.The lethal temperature of hyphae of Phytophthora cactorum was 53 ?.The six kinds of fungicides had different bactericidal effects on Fusarium oxysporum and Phytophthora cactorum infestans.In contrast,the control effect of 240g/l thiadiamide was not ideal,and no antibacterial effect on Fusarium oxysporum was obtained,However,the bactericidal effect of Phytophthora cactorum was higher.Comprehensive antibacterial effect of six fungicides 68% fine nail cream,manganese zinc and 30% metal cream,badoin two fungicides had good bactericidal effect,so it would be recommended to use these two fungicides for the control of strawberry root rot.