辣椒溶杆菌NF87-2防治瓜类蔬菜蔓枯病的研究

由黑腐球壳菌Didymella bryoniae引起的瓜类蔬菜蔓枯病是一种重要真菌土传病害，造成瓜类蔬菜生产上重大的经济损失。本研究以蔓枯病菌DB-20为靶标菌，采用平板对峙培养法，测定了拮抗细菌及其代谢产物对蔓枯病菌菌丝生长和孢子萌发的的室内抑制作用，拮抗细菌和蔓枯病菌同时接种后，测定西瓜种子的发芽率和出苗率，采用盆栽试验研究拮抗细菌对黄瓜蔓枯病的防治效果。结果表明，辣椒溶杆菌Lysobacter capsici NF87-2对蔓枯病菌菌丝生长的室内抑制率为81.6%，菌株NF87-2及其次生代谢物对蔓枯病菌孢子萌发的抑制率分别为59.4%和67.2%。蔓枯病菌DB-20处理的京欣一号西瓜种子发芽率和出苗率分别为48%和38%，菌株NF87-2＋DB-20同时接种处理组的西瓜种子发芽率和出苗率分别为83%和82%。菌株NF87-2发酵液及其代谢产物对黄瓜蔓枯病的盆栽防治效果分别为81.6%和66.5%。辣椒溶杆菌NF87-2是一株具有较好生防应用潜力的拮抗菌株，有望开发成防治瓜类蔬菜蔓枯病的生物杀菌剂。

Study of Biocontrol Efficacy on Cucurbit Gummy Stem Blight by Lysobacter capsici NF87-2

Cucurbit gummy stem blight caused by Didymella bryoniae is an important soil-borne fungal diseases and cause significant economic losses. In order to screen and evaluate the antagonistic bacteria against D. bryoniae, the antagonistic activity in vitro and control effect on cucurbit gummy stem blight in pot experiment were investigated in this study. Antagonistic examination against D. bryoniae in vitro revealed that Lysobacter capsici NF87-2 showed strong and steady antagonism, with the inhibition rate of 81.6%. Inhibition rates of strain NF87-2 and its secondary metabolites on spore germination of D. bryoniae were 59.4% and 67.2%, respectively. Seed germination percentage and seedling emergence rate were 83% and 82%, respectively, after inoculated with L. capsici NF87-2 and D. bryoniae together while 48% and 38%, respectively, after only inoculated with D. bryoniae. The fermented liquid and its secondary metabolite of strain NF87-2 could also effectively control gummy stem blight on cucumber in pot experiment, with the control efficiency of 81.6% and 66.5%, respectively. Therefore, strain NF87-2 was a prospective antagonistic bacterium and it is hopeful to be developed as a biological pesticide to control cucurbit gummy stem blight.