种子处理对西瓜苗期3种病害的防治效果

Effect of seed treatment on the control of three watermelon diseases at seedling stage

为了筛选防治西瓜苗期立枯病、猝倒病和枯萎病的有效种子处理剂,在人工控制的条件下,选择了6.25%精甲·咯菌腈悬浮种衣剂、2.5%咯菌腈悬浮种衣剂、3.5%精甲·咯菌腈悬浮种衣剂、72%霜霉威盐酸盐水剂和50%多菌灵可湿性粉剂5种杀菌剂对西瓜种子进行处理。分析了处理种子的活力和幼苗的生长特性;以及在人工接种3种病原菌的胁迫下不同处理种子在基质中的出苗率和发病情况。结果表明:5种杀菌剂对种子的活力和幼苗的生长特性没有明显的影响,但3.5%精甲·咯菌腈悬浮种衣剂包衣降低了每株幼苗的鲜重,50%多菌灵可湿性粉剂浸种则提高了幼苗的整齐度。接种西瓜立枯病菌和猝倒病菌的种子出苗率降低,接种西瓜枯萎病菌的种子出苗率没有明显变化;6.25%精甲·咯菌腈悬浮种衣剂和2.5%咯菌腈悬浮种衣剂包衣种子对西瓜立枯病的防效最佳,72%霜霉威盐酸盐水剂浸种对西瓜猝倒病有一定的防效,对西瓜枯萎病的防治没有特别有效的药剂。

The effects of watermelon seed treatment with five fungicides of 6.25% metalaxyl-M·fludioxonil FSC,2.5% fludioxonil FSC,3.5% metalaxyl-M·fludioxonil FSC,72% propamocarb hydrochloride AS and 50% carbendazim WP on three seedling diseases control were investigated,and their influences on seed germination and seedling growth were also evaluated.The results showed that there were no obvious influences of five fungicides on seed vigor and seedling growth except that 3.5% metalaxyl-M·fludioxonil FSC decreased fresh weight of seedling and 50% carbendazim WP increased seedling uniformity.The seedling emergence rates were obviously decreased after the seeds inoculated with Rhizoctonia solani and Pythium aphanidermatum in seedling box.The treatments of seed coated with 6.25% metalaxyl-M·fludioxonil FSC and 2.5% fludioxonil FSC showed the best control efficacy against R.solani while the treatment of seed soaked with 72% propamocarb hydrochloride AS showed the best control efficacy against P.aphanidermatum.There was no effective fungicide against Fusarium oxysporumin this study.