不同生防药剂对燕麦叶斑病的防治效果

A study on the effectiveness of bio-medicaments in controlling oat leaf spot

为明确生防药剂对燕麦(Avena sativa)叶斑病的防效,本研究选用4种不同类型的生防药剂,以2种化学杀菌剂为对照,在甘肃省山丹县对田间自然发病的燕麦叶斑病进行防治。结果表明:第1次施药后7 d,生防药剂的防效(56.81%~63.59%)普遍低于化学杀菌剂25%吡唑醚菌酯悬浮剂(防效71.11%)和43%戊唑醇悬浮剂(防效73.60%)。第2次施药后7 d,供试药剂的防效与第1次施药后7 d相比均有所提高,其中哈茨木霉(Trichoderma afroharzianum)的防效较第1次增加了27.39%,增幅最大。第2次施药后20 d,各药剂的防效较第2次施药后7 d有所降低,但生防药剂的防效降幅较小而化学杀菌剂的防效大幅降低。枯草芽孢杆菌(Bacillus subtilis)的防效最高,达80.34%。另外,1×10^(11)cfu·g^(-1)枯草芽孢杆菌处理显著提高了燕麦旗叶叶绿素相对含量、千粒重和种子产量(P<0.05),3个指标分别较未施药区增加了26.13%、13.22%和13.09%。综合防效、持效性及燕麦种子产量等指标,微生物源杀菌剂1×10^(11)cfu·g^(-1)枯草芽孢杆菌是防治燕麦叶斑病的最佳药剂,在发病初期开始喷施,间隔7 d喷第2次,可有效控制叶斑病病情,并可通过提高燕麦旗叶叶绿素相对含量和千粒重从而提高种子产量。

In order to determine the effectiveness of biocontrol agents against oat leaf spot,four biocontrol agents were tested,and two chemical fungicides were used as controls for the control of naturally occurring oat leaf spot in Shandan County,Gansu Province.The results showed that 7 days after the first application,the control effect of the biocontrol agent(56.81%~63.59%)was generally lower than that of the chemical fungicides,25%pyraclostrobin suspension(71.11%)and43%tebuconazole suspension(73.60%).Seven days after the second application,the control effect of the test agents was greater than that of 7 days after the first application.Among the agents tested,the control effect of Trichoderma harzianum increased by 27.39%compared with the first application,which was the largest increase.Twenty days after the second application,the control effect of each agent was lower than that of 7 days after the second application.However,the control effect of biocontrol agents decreased slightly while the chemical fungicides decreased significantly.Bacillus subtilis had the highest control effect at 80.34%.In addition,treatment with 1×10^(11)cfu·g^(-1)Bacillus subtilis significantly increased the relative content of oat flag leaf chlorophyll,thousand-grain weight and seed yield(P<0.05),and the three indexes increased by 26.13%,13.22%,and 13.09%,respectively,compared with the control.Considering the comprehensive control effect,sustained effect,oat seed yield,and other indicators,the microbial source fungicide 1×10^(11)cfu·g^(-1)Bacillus subtilis is the best agent for preventing and controlling oat leaf spot.Spraying should be started at the beginning of the disease,with a second spraying after 7 days.In addition to controlling leaf spot disease,this agent can also increase seed yield by increasing the relative content of chlorophyll and 1000-seed weight of oat flag leaves.