噻呋酰胺与嘧菌酯混配对马铃薯黑痣病菌增效作用及其田间防效
Synergistic interaction and field control effect of mixtures of thifluzamide with azoxystrobin against Rhizoctonia solani

为明确噻呋酰胺与嘧菌酯混配对马铃薯黑痣病菌Rhizoctonia solani的增效作用及对马铃薯黑痣病的田间防效，采用菌丝生长速率法和田间药效试验测定二者混配组合对其的联合毒力，分别用Wadley法和Abbott法评价混配组合的增效作用，并比较拌种、沟施及苗期茎基部喷淋3种施药方式对黑痣病的田间防效。结果表明，噻呋酰胺与嘧菌酯以质量比3∶1、2∶1、1∶1和1∶2进行混配时抑制马铃薯黑痣病菌菌丝生长的增效系数分别为1.7、2.7、2.5和1.9，其中2∶1和1∶1的混配组合增效作用较为明显。240 g/L噻呋酰胺悬浮剂与250 g/L嘧菌酯悬浮剂1∶1桶混以240 g(a.i.)/hm2沟施对马铃薯黑痣病的防效优于拌种和苗期茎基部喷淋的防效，沟施方式下对植株黑痣病的防效为65.3%，对薯块黑痣病的防效为71.6%，增效系数为1.1，表现增效作用。表明噻呋酰胺与嘧菌酯有效成分质量比1∶1的混配组合以240 g(a.i.)/hm2为推荐剂量沟施可有效防治马铃薯黑痣病。
In order to elucidate synergism against Rhizoctonia solani using the mixtures of thifluzamide with azoxystrobin and to control disease of potato black scurf in the field, the joint-toxicity of the mixtures of the two fungicides against R. solani was examined through the mycelial growth rate assay and the field trials on the controlling efficacy was conducted. The synergism of the mixtures was assessed with the method of Wadley formula and Abbott formula, respectively. The control effects of the mixtures against potato black scurf were treated in field trials of seed dressing, furrow application and spraying to the stem base of seedlings on controlling efficacy against potato black scurf. The results showed that the synergistic ratios of the mixtures of thifluzamide with azoxystrobin at the ratios of 3∶1, 2∶1, 1∶1 and 1∶2 were 1.7, 2.7, 2.5, and 1.9, respectively. The mixtures of thifluzamide with azoxystrobin at the ratios of 2∶1 and 1∶1 exhibited the more obvious synergistic interaction. The furrow application of tank mixture of thifluzamide 240 g/L SC with azoxystrobin 250 g/L SC at the ratio of 1∶1 at the rate of 240 g (a.i.)/hm2 gave higher control efficacy than seed dressing and spraying to the stem base of seedlings and exhibited synergistic interaction with synergistic ratio of 1.1, the control efficacies against potato black scurf in potato stems and tubers by furrow application were 65.3% and 71.6%, respectively. It indicated that the furrow application of tank mixture of thifluzamide 240 g/L SC with azoxystrobin 250 g/L SC at the ratio of 1∶1 at the rate of 240 g (a.i.)/hm2 could be more effectively for the control of potato black scurf.