Abstract: Investigation of tolarance to Tricyclazole in rice blast (Magnaporthe grisea, Anamorph: Pyricularia grisea) from major rice cultivation regions of Heilongjiang province in 1995-1997 showed that the resistant isolates were found in many areas. The average EC₅₀ of Tricyclazole to sensitive isolates in the regions of Harbin, Mudanjiang, Jiamusi, Suihua and some state farms were 10-20 mg/kg, 20-40 mg/kg, 50 mg/kg, 50 mg/kg, 40 mg/kg respectively. The average EC₅₀ of resistant isolates were all far surpass 50 mg/kg. The average EC₅₀ of resistant isolates to Tricyclazole is about 1. 25-5 times to sensitive ones.

Key words: rice blast, fungicide, fungicide tolerance, inhibition

摘要： 采用室内抑菌试验方法，对来自黑龙江省不同地区160份稻瘟病标样中的98个纯菌株进行抗药性测定。结果表明，三环唑对不同地区稻瘟病菌的平均抑制中浓度(EC50)有很大差异。敏感菌株的平均抑制中浓度，哈尔滨菌株为10～20 mg/kg，牡丹江菌株为20～40 mg/kg，佳木斯和绥化菌株均接近50 mg/kg，国营农场的菌株接近40 mg/kg，抗性菌株平均抑制中浓度均大于50 mg/kg。本试验结果说明，黑龙江省大部分稻区的稻瘟病菌对三环唑已产生一定的抗性。抗性菌株抑制中浓度大约是敏感菌株的1.25～5倍。

关键词: 稻瘟病菌, 抗药性, 抑制, 杀菌剂