不同生育阶段黄瓜菌核病菌对几种三唑类杀菌剂的敏感性

Susceptivity of Sclerotinia sclerotiorum to Triazole Fungicides at Different Growth Stages

采用菌丝生长速率法测定了6种三唑类杀菌剂和4种其他杀菌剂抑制黄瓜菌核病菌Sclerotinia sclerotiorum（Lib．）de Bary菌丝生长的毒力，同时测定了其对菌核形成及萌发的抑制作用。结果表明，甲基硫菌灵抑制菌丝生长的毒力最低，EC轴值为65．75μg／mL；己唑醇和戊唑醇的抑制活性较高，EC50值分别为0．09和0．16μg／mL，毒力分别是甲基硫菌灵的763．7和423．4倍；其次是丙环唑、氟硅唑、腈菌唑，毒力是甲基硫菌灵的137．3-286．6倍；再次为三唑酮，毒力仅为甲基硫菌灵的20．6倍；腐霉利、菌毒清抑制菌丝生长的毒力较低，EC50值均大于10μg/mL。在EC50值浓度下，所有供试药剂对菌核形成及其数量均没有影响，但三唑类杀菌剂对菌核单重影响较大，各处理所形成的菌核单重降低率均在70％以上；而当药剂浓度在10μg／mL以下时，己唑醇等三唑类杀菌剂对菌核萌发均没有影响。

The inhibition bioactivities on mycelial growth of 6 triazole fungicides and 4 others against Sclerotinia sclerotiorum （ Lib. ） de Bary were determined by mycelial growth rate method in lab, and examed their effects on sclerotium formation and sclerotium germination. The results showed that thiophanate-methyl had the weakest inhibitory effect on mycelial growth, its EC50 value was 65.75 μg/mL. Hexaconazole and tebuconazole had more significant inhibitory effects, their EC50 values were 0.09 μg/mL and 0. 16 μg/mL, relative toxicity coefficient to thiophanate-methyl were 763.7 and 423.4 times, respectively. Secondary were propiconazol, mvclobutanil and flusilazole, which relative toxicities ranging from 137.3 to 286.6 times of thiophanate-methyl. Triadimefon had lower inhibition, its relative toxicity was 20.6 times of thiophanate-methyl. The EC50 values of procymidone and Junduqing were more than 10 μg/mL. At the concentration of EC50, all the tested fungicides did not affect the number of sclerotium. But the weight of sclerotium fell more than 70% after treated with triazole fungicides. All the triazole fungicides had no effect on the germination of sclerotium below the concentration of 10 μg/mL.