Abstract:

An isolate of indigenous fungus Fusarium avenaceum GD\|2 was isolated from infected wild oats (Avena fatua L.) in Guide County, Qinghai Province. Laboratory pathogenicity determination, large\|scale culture of indoor spores and field plot test were conducted on this isolate as a biocontrol agent for wild oats. Under greenhouse conditions, watery brown disease spots appeared on the inoculated plants 48 h after inoculation, and eventually the leaf blades were senescence and died. The motidity were 90% and 95%, respectively during 2 and 4 leaf stage at 7 d. At the same time, the state of disease reached the highest rank, which had obvious inhibitory effect on plant height. The experiment result of liquid\|solid joint culture indicated that the highest spore production was obtained at the initial moisture content of 59%~61%, 28℃, initial pH 7.0, and 0.5% (V/V) initial inoculums size (1.0×106 conidia/mL). The highest spore production could reach 7.58×108 conidia/g after incubating for 7 d. Under field conditions, the mixed treatment of Fusarium avenaceum with quizalofop\|p\|ethyl could significantly reduced the biomass in wild oats. Leaf surface moisture condition led to the lower preventing effect in 2012 than 2011. No matter under greenhouse or field conditions, wild oats were susceptible to Fusarium avenaceum. Therefore, this research result indicated that Fusarium avenaceum GD\|2 is a potential bio\|herbicide for controlling wild oats.

Key words: bio\, herbicide；Fusarium avenaceum；Avena fatua L.；biological control, mass production；pathogenicity determination

摘要：

从青海省贵德县患病野燕麦叶片上分离获得燕麦镰刀菌，对该生防菌进行了室内致病性测定、室内孢子大批量培养和大田小区试验研究。室内条件下接种野燕麦48 h后出现水褐色病斑，最终导致叶片衰老死亡，在2、4叶期7 d时的发病率分别达到90%和95%，同时病情级别达到最大，而且对株高具有明显的抑制作用。通过液-固体联合培养试验表明，在含水量59%～61%、28℃、初始pH 7.0、初始接种量0.5%(1×106个孢子/mL)的麦麸与玉米粉(1∶1)培养基中，培养7 d时，产孢量最大(7.58×108个孢子/g)。在田间条件下燕麦镰刀菌与精喹禾灵混合使用能显著降低野燕麦的生物量，野燕麦叶片表面的湿度条件导致2012年对野燕麦的防除效果低于2011年。不论在是在室内和大田条件下，野燕麦都对野燕麦镰刀菌表现敏感。因此，该研究结果表明野燕麦镰刀菌株GD\|2可作为防除野生燕麦的潜力生防菌。

关键词: 生物除草剂；燕麦镰刀菌；野燕麦；生物防治；大批量培养；致病性测定