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

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