防治西洋参立枯病木霉菌株的筛选鉴定及其小区防治效果

摘要：利用平板对峙实验及小区试验，筛选高效防治西洋参立枯病的木霉菌株，并采用ITS（internal transcribed spacer)序列分析与形态学特征相结合的方法进行种类鉴定。结果表明，供试木霉菌株在PDA平板上对立枯丝核菌(R. solani)均有抑制作用，菌株HB20111效果最好，抑制率达99.33%;菌株HB20111对西洋参立枯病的小区效果显著，与其他处理间存在显著性差异(P<0.05);第1年拌种处理对西洋参立枯病的防治效果、单株参增重率及总参增重率分别达71.81%、33.54%和92.75%；第2年蘸根处理对西洋参立枯病的防治效果、单株参增重率及总参增重率分别达91.04%、158.06%和1 369.34%;菌株HB20111的分生孢子梗为典型的单侧分枝，其他形态学特征同深绿木霉(T. atroviride)一致，ITS序列与T. atroviride同源性达100.0%，将菌株HB20111鉴定为T. atroviride。HB20111生长速度快，产孢能力强，生防效果高，有望替代化学杀菌剂应用于西洋参种植中。

Screening and identification of Trichoderma spp. against seedling blight of Panax quinquefolium L. and its control efficiency on the plot

Trichoderma strains effectively controlling the seedling blight of Panax quinquefolium L. were screened using dual-culture antagonistic activity assay and a plot experiment and identified by internal transcribed spacer (ITS) sequence analysis and morphological characteristics. The result showed that all test Trichoderma strains could inhibit R. solani on a PDA plate, among which strain HB20111 had the highest inhibition ratio of 99.33%. In the plot experiment, strain HB20111 significantly controlled the seedling blight of P. quinquefolium L., with a significant difference compared to other treatments (P<0.05). For seed dressing used in the first year, the control efficiency, weight gain rate of a single plant and weight gain rate of total plants reached 71.81%, 33.54% and 92.75%, respectively.And for root adhesion treatment in the second year, the values of the three parameters were 91.04%, 158.06% and 1369.34%, respectively. The strain HB20111 was identified as T. atroviride, with typical single branched conidiophores as its other morphological characteristics were consistent with T. atroviride and ITS sequence was 100.0% homologous with that of T. atroviride. HB20111 is expected to substitute chemical fungicide in the production of P. quinquefolium L. due to fast growth, strong sporulation ability, and high control efficiency.