The inhibitory activity of 3 kinds of isothiocyanate (ITC) chemicals (Dazomet, Mustard oil and Phenyl isothiocyanate) to the mycelial growth and spore germination of soil - borne chilli pepper pathogens was tested in the laboratory by using plate culture method, and the control effect of these compounds against chilli pepper blight caused by Phytophthora capsici was investigated by soil suffocation treatment and potted trial. The results showed that the difference between volatile toxicity and involatile toxicity of ITCs was great. Their volatile toxicity ranked as follows: Mustard oil > Dazomet > Phenyl isothiocyanate. The involatile toxicity of Phenyl isothiocyanate was stronger than that of Mustard oil. The aromatic ITCs had weaker volatile toxicity than the aliphatic ITCs, but the aromatic ITCs were more toxic when they were dissolved in the medium. The inhibitory activity of ITCs against spore germination was much stronger than that against mycelial growth. The pot culture trial showed that Dazomet and Mustard oil were more efficient in controlling pepper blight than Phenyl isothiocyanate, the control effect of 0.03% (w/w) Dazomet or Mustard oil was excellent and got to 100% , and the amount of Phytophthora capsici in the rhizospheric soil was 0 after control by plate count method. The field trial revealed that the incidence of soil - borne disease on pepper was decreased by 60% after one year when the obstacle soil was treated with 98% Dazomet in the greenhouse, and the yield of pepper was increased.%采用室内含药平板培养的方法分别测定了棉隆、芥末精油、异硫氰酸苯酯3种异硫氰酸酯类化学药剂对常见土传辣椒病原菌菌丝生长和孢子萌发的影响.并通过土壤熏蒸及盆栽试验,研究了这些药剂对辣椒疫病的防治效果.结果表明,异硫氰酸酯类化学药剂的挥发性毒力和非挥发性毒力差异很大.挥发性毒力:芥末精油＞棉隆＞异硫氰酸苯酯；非挥发性毒力:异硫氰酸苯酯＞芥末精油.芳香族异硫氰酸酯挥发性毒力弱于脂肪族异硫氰酸酯,但其溶于培养基时毒力较强.异硫氰酸酯类化学药剂抑制孢子萌发的作用强于抑制菌丝生长的作用.盆栽试验结果显示,棉隆和芥末精油对辣椒疫病的防效高于异硫氰酸苯酯,前两种药剂用量为0.03％(质量分数)时,防效可以达到100％,且平板计数结果表明,根际土中辣椒疫霉的数量为0.田间试验表明,98％棉隆微粒剂处理辣椒大棚连作障碍土壤,可使次年土传病害发生率降低60％,并增加辣椒产量.
展开▼
