甘肃省定西市马铃薯黑痣病菌菌丝融合群的鉴定及药剂筛选

Fungicide screening and identification of anastomosis groups of Rhizoctonia solani on potato

马铃薯黑痣病立枯丝核菌(Rhizoctonia solani)菌丝存在遗传分化现象。从定西市马铃薯产区采集茎部和薯块病样80份进行融合群测定。结果表明,80株菌株中与标准菌株AG3融合的占总数的70.0%、与AG4-HG-Ⅱ融合的占15.0%、与AG2-1融合的占7.5%。为了有效控制马铃薯黑痣病,采用生长速率法在室内选取9种杀菌剂进行药效评价。结果表明:30%噻呋酰胺悬浮剂EC50最低,为0.015 2μg/mL;其次是40%氟胺·异菌脲悬浮剂、3%多抗霉素可湿性粉剂和250g/L嘧菌酯悬浮剂,其EC50分别为0.064 1、0.129 3和0.176 7μg/mL;EC50最大的是25.75%多抗·福美双可湿性粉剂,为2.930 4μg/mL。田间拌种,30%噻呋酰胺悬浮剂和250g/L嘧菌酯悬浮剂防效较好,达70%以上,值得在生产中推广。

Mycelium of potato black scurf （Rhizoctonia solani） existed genetic differentiation phenomenon. Anas- tomosis group （AG） identification of 80 diseased potato stems and tubers sampled from Dingxi City showed that 70% strains could fused with the standard strain AG3, 15% with AG4-HG-11, and 7.5% with AG2-1. Mean- while, the toxicities of 9 fungicides to R. solani were evaluated by the mycelial growth rate method indoors. The re- sults showed that 30% trifluzamide SC had the high toxicity with the EC^0 value of 0. 015 2 μg/mL, followed by 40% fluazinam iprodione SC, 3% polyoxin WP and 250 g/mL azoxystrobin SC, with the values of 0.064 1, 0. 129 3 and 0. 176 7μg/mL, respectively. 25.75% polyoxin ~ thiram WP was the lowest toxicity with the value of 2. 930 4 μg/ mL. Field trials demonstrated that 30% trifluzamide SC and 250 g/mL azoxystrobin SC by seed dressing had good con- trol effect with the efficacy of more than 70%, which can be recommended in potato production.