西瓜种传枯萎病病原菌鉴定及其防控方法

Identification and control of seed-borne pathogen of watermelon wilt disease

为明确西瓜生产中一种幼苗新病害的病原菌种类,分离纯化获得菌株XG1601,并测定其致病性,利用形态学特征和rDNA ITS序列分析技术明确了该病原菌的分类地位,研究了不同杀菌剂及干热处理西瓜种子对该病害的防治效果。结果显示,结合形态特征及rDNA ITS序列技术分析最终确定菌株XG1601为尖孢镰刀菌Fusarium oxysporum f. sp. niveum。该病原菌为种子传带,引起西瓜种传枯萎病,西瓜种子种皮和种胚的带菌率分别为5.4%和1.7%,在温室中播种30 d左右,幼苗的发病率可达35.7%～41.1%。种子处理对该病害的防治试验结果显示,6.25%精甲霜灵?咯菌腈悬浮种衣剂和2.5%咯菌腈悬浮种衣剂包衣种子对病害的防治效果分别为67.0%和68.6%,80℃干热处理种子72～96 h的防治效果均为100.0%,且对处理种子的发芽势、出苗率和鲜重均无不利影响。说明80℃干热处理种子72～96 h对西瓜种传枯萎病的防治效果最好。

To clarify the pathogen of one new watermelon seedling disease, the strain XG1601 was obtained from the symptomatic seedlings, and the strain was identified by the morphological characteristics and rDNA ITS sequence analysis. The control effects of dry heat treatments and different fungicide treatments on this disease were tested. The results showed that strain XG1601 was identified as Fusarium oxysporum f. sp. niveum. The rates of infected seed coat and embryo were 5.4% and 1.7%, respectively. After sowed in the greenhouse at 30 d, the rate of diseased seedlings was 35.7%-41.1%. The disease control efficacies of the treatments with seeds coated with 6.25% metalaxy1-M?fludioxonil seedcoating suspension and 2.5% fludioxonil seed-coating suspension reached 67.0% and 68.6%, respectively. The dry-heat treatment at 80℃ for 72-96 h showed the best control efficiency(100%) against Fusarium wilt of watermelon without negative influence on seed germination energy, seedling emergence rate and seedling fresh weight. The results indicated that the dry-heat treatment was the best disease management strategy.