壳聚糖防治金叶女贞褐斑病的研究

Study on the Control of Brown Spot Disease of Ligustrum vicaryi with Chitosan

[目的]对壳聚糖防治金叶女贞褐斑病的效果进行了研究,为壳聚糖在防治金叶女贞褐斑病上的应用提供参考。[方法]采用病原菌的分离培养及人工感染的方法,对壳聚糖体外抑制金叶女贞褐斑病菌以及预防和治疗金叶女贞褐斑病进行了试验。[结果]3种分子量的壳聚糖体外抑菌效果都很好,其中分子量5万～6万效果最好,1万～2万次之,6000效果稍差;壳聚糖预防试验中,分子量5万～6万和1万～2万的预防效果都很好,在2.0%浓度时,可以达到免疫效果,分子量6000的效果较差,感病率51.37%～83.32%;治疗效果与治疗时间关系密切,24h施药时各分子量的2.0%浓度也达到免疫效果;36和48h施药时分子量1万～2万和5万～6万的高浓度治疗效果不错,其他均较差。[结论]分子量5万～6万、浓度1.5%～2.0%的壳聚糖预防和治疗金叶女贞褐斑病,能够达到很好效果,治疗时间以感菌后48h以内为好。

[Objective] The reference for the application of chitosan in the control of brown spot disease of Ligustrum wicaryi was provided through the research on its controlling efficiency.[Method] The experiment in the inhibition of chitosan to the pathogen of brown spot disease of Ligustrum wicaryi,and the preventive and controlling effect of chitosan on brown spot disease of Ligustrum wicaryi were conducted with the isolation culture of its pathogen and artificial infection to the plant.[Results] The good efficiency of the chitosan with three molecular weights on the control of the disease was showed and the antifungal activity in vitro of the chitosan with molecular weight of 50-60 kD was best;then,10-20 kD and last,6 kD.The preventive effect of the chitosan with molecular weight of 50-60 kD and 10-20 kD was good and no disease appeared while its concentration was 2.0%;the disease rate was 51.37%-83.32% under the treatment of the chitosan with molecular weight of 6 kD at the concentration of 2.0%.There was close relation between the controlling effect and treating time.At the 24th hour,the application of the chitosan with all types of molecular weights could produce good controlling effect.The good controlling effect from the application of the chitosan with molecular weight of 50-60 kD and 10-20 kD could be formed at the 36th hour and 48th hour;and other treatments were not good.[Conclusion] The good preventive and controlling effect of the chitosan with molecular weight of 50-60 kD at the concentration of 1.5%-2.0% on brown spot disease of Ligustrum wicaryi could be produced and the best treating time was within 48 hours after its infection.