杀菌剂对芒果细菌性角斑病菌的室内毒力及田间防效

细菌性角斑病是芒果生产上的重要病害,为筛选有效的防治药剂,采用浑浊度法对22种杀菌剂进行室内抑菌活性初筛,对抑菌活性较好的药剂采用平板菌落计数法进行室内毒力及田间药效试验。室内抑菌活性表明,四霉素、辛菌胺醋酸盐、溴菌腈、乙蒜素和噻霉酮抑菌作用最强,2 mg/L处理浓度下抑菌率均达90%以上,其次为丙硫唑和中生菌素,10 mg/L处理下抑菌率在75%以上;溴菌腈、噻霉酮、丙硫唑、春雷霉素和噻森铜的EC₅₀值分别为0.048、0.103、0.900、21.970、189.347 mg/L。田间试验显示,施药后30 d,20%噻唑锌SC750倍防效最高,可达75%以上;其次为3%噻霉酮ME1000倍、20%丙硫唑SC1000倍和25%溴菌腈EC1000倍,防效均在70%以上;46%氢氧化铜WG保护作用最高,防治后病叶率最低。据此,氢氧化铜、噻唑锌、噻霉酮、丙硫唑和溴菌腈可作为防治芒果细菌性角斑病的供选药剂。

Assessment of Fungicides for in vitro and in vivo Activity Against Xanthomanas campestris pv. mangiferaeindicae

Mango bacterial black spot (MBBS) caused by Xanthomonas campestris pv. manganiferaeindicae (Xcm) is a risk plant disease in mango orchards. In order to screen an effective fungicide for controlling MBBS, the bacteriostatic activity of 22 fungicides against MBBS were assessed by th turbidimeter test in the laboratory, and the toxicity of the fungicides with good antibacterial activity was tested by the method of plate culture count and the control efficacy were carried out in the field. Laboratory bioassay results showed that the inhibitory effect of tetramycin, octylamine acetate, bromothalonil and benziothiazolinone was strong, with an inhibitory rate 90% treated with 2 mg/L, followed by pothioconazole and zhongsengmycin with an inhibitory rates up to 75% at 10 mg/L. Except for oxine-copper, the bacteriostatic activity of copper fungicides was relatively low. The toxicity of bromothalonil, benziothiazolinone, pothioconazole, kasugamycin and saisentong to Xcm was calculated, with EC₅₀ of 0.048, 0.103, 0.900, 21.970 and 189.347 mg/L, respectively. At 30 days after treatment, the result of the field trial indicated that 20% zinc-thiazole SC 750 times solution (TS) had the highest control efficacy on the disease and its control effect reached 75%, followed by 3% benziothiazolinone ME, 20% pothioconazole SC and 25% bromothalonil EC reached above 70% control efficacy at 1000 TS. Beyond that, 46% copper hydroxide WG showed a better protective effect than other fungicides with lowest diseased leaf rate after treatment. Accordingly, copper hydroxide, zinc-thiazole, benziothiazolinone, pothioconazole and bromothalonil could be used as the chemicals for controlling mango bacterial black spot.