广西烟草黑胫病菌对甲霜灵的敏感性检测

【目的】研究广西烟草黑胫病菌对甲霜灵的敏感性,为烟草黑胫病药剂防治提供科学依据。【方法】采用菌落生长速率法对从广西主要烟区采集分离到的196株烟草黑胫病菌株进行对甲霜灵的敏感性测定。【结果】甲霜灵对196株菌株的EC50在0.0691-1.0243μg/mL,平均EC50为0.3618±0.0297μg/mL;来自田林县的菌株TL05为最敏感菌株,EC50为0.0691μg/mL;来自靖西县画洞镇的菌株ZXHD12为最耐药菌株,EC50为1.0243μg/mL;各烟区烟草黑胫病菌对甲霜灵的敏感性有一定差异,其中南丹、田林县的菌株较敏感,而隆林、靖西、德保、富川县的部分菌株较耐药;196株菌株中,敏感型、一般耐药型和耐药型菌株分别占1.53%、66.84%和31.63%。【结论】广西烟草黑胫病菌已对甲霜灵产生不同程度的抗性,甲霜灵作为生产上防治烟草黑胫病的主要药剂具有较大的风险,建议生产上甲霜灵与其他杀菌剂进行轮换使用。

Detection of Phytophthora parasitica var.nicotianae sensitivity to metalaxyl in Guangxi

Objective]The present experiment was conducted to study the sensitivity of Phytophthora parasitica var. nicotianae to metalaxlyl in Guangxi in order to apply the proper control measures for its spread. Method]Sensitivity of 196 Phytophthora parasitica var. nicotianae strains isolated from the main tobacco areas of Guangxi to metalaxlyl was tested by observing the growth rate of fungal strains. Result]EC50 values of 196 isolates ranged from 0.0691 to 1.0243 μg/mL, and the mean EC50 value was 0.3618±0.0297 μg/mL. The isolate TL05 from Tianlin County was the most sensitive one, with the EC50 value of 0.0691 μg/mL, while the isolate ZXHD12 from Huadong Town, Jingxi County was the most resistant, with the EC50 value of 1.0243 μg/mL. A significant difference among the sensitivities of isolates from different sites has been observed. The isolates from Nandan and Tianlin County were the most sensitive, while those from Longlin, Jingxi, Debao and Fuchuan County were the most resistant. The frequencies of sensitive, intermediate and resistant isolates to metalaxyl were 1.53, 66.84 and 31.63%, respectively. Conclusion]A low level of resistance to metalaxyl has been observed in Phytophthora parasitica var. nicotianae in Guangxi. It is, therefore, suggested that metalaxyl should be alternated with other fungicides for proper control of the tobacco black shank.