旱地麦田禾谷镰孢土壤带菌研究

用胨-PCNB-四环素选择性培养基涂布平板法检测了关中灌区麦田土壤中禾谷镰孢接种体数量。结果表明,除多年休闲的麦田外,前作物为水稻、玉米、大豆、首蓿、蔬菜的麦田都带有禾谷镰孢,接种体密度幅度为每克土壤58～2800个;在表土中以5cm深处土壤带菌密度最高,禾谷镰孢在麦田土壤中可形成厚垣孢子;麦田土壤中还含有大量带菌细小植物残渣,带菌率1.5％～10％,其密度为每亩(0.31～7.67)×10~4个。

Inoculum Population of Fusearium graminearum in Soil of the Arid Wheat Fields

Soil inoculum population of Fusearium graminearum was investigated in the irrigated area of Central Shaanxi Province using peptone-PCNB tetracyclin selective medium and soil-spreading plate toehnique.The pathogenwas found in all the soil samples from the arid wheat fields with the previouscrops including rice,corn,soybean,alfalfa and vegetale crops except thelong-term wheat fallow fields.Population density of the pathogen ranged 58-2800 propagules/g of dry weight soil.Propagules of the pathogen with thehighest density existed in top soil at the depth of 5 cm.Macroconidia of F. graminearum added to nonsterile soil converted to thick-wall chlamydospores.The pathogen was also recovered from the fine pieces of plant debris andorganic manure,with the rate of 1.5% to 10%,and the density ranged (0.31-7.67)×10⁴/mu.