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

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,EC50值为65.75 μg/mL;己唑醇和戊唑醇的抑制活性较高, EC50值分别为0.09和0.16 μg/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10 μg/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10 μg/mL以下时,己唑醇等三唑类杀菌剂对菌核萌发均没有影响。

Susceptivity of Sclerotinia sclerotiorum to Triazole Fungicides at Different Growth Stages

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.