铁皮石斛炭疽病防治药剂的室内筛选与应用技术

Application and Screening of Fungicides for Controlling Anthracnose in Dendrobium candidum Caused by Colletotrichum gloeosporioides

[目的]筛选铁皮石斛炭疽病的防治药剂,并形成应用技术。[方法]室内测定16种杀菌剂的离体抑菌活性,并进行联合作用评价和田间药效试验。[结果]苯醚甲环唑和咪鲜胺对铁皮石斛炭疽病菌具有很强的抑菌活性,其EC_(50)值分别为1.76、0.43 mg/L;筛选明确了苯醚甲环唑与咪鲜胺配比为1∶4时,具有最大的毒力(EC_(50)值为0.38 mg/L)和最大共毒系数(CTC为133.31),表现出一定的增效作用。苯醚甲环唑、咪鲜胺及其复配(配比为1∶4)不同剂量,对铁皮石斛炭疽病的田间防效在75%以上(75.62%~87.85%);复配处理(苯醚甲环唑100 mg/L+咪鲜胺400 mg/L)的防效在85%以上,极显著好于两单剂(P<0.01)。[结论]苯醚甲环唑与咪鲜胺复配对铁皮石斛炭疽病具有更优的控制效果,可在生产上推广使用。

[Aims] The present study aims to screen out effective fungicides for controlling anthracnose in Dendrobium candidurn and to establish application technique. [Methods] Inhibitory activities of 16 fungicides were examined by methods of mycelia growth and conidial germination rate. The co-toxicity of difenoconazole and prochloraz to Colletotrichum gloeosporioides was assessed, and field trials were also carried out. [Results] Both difenoconazole and prochloraz had good bioactivity against C. gloeosporioides with a 50% effective concentration （ECs0） of 1.76 and 0.43 mg/L, respectively. When the mass ratio was 1：4, the strongest activity （ECs0 of 0.38 mg/L） and the maximum co-toxicity coefficient （CTC） of 133.31 were obtained. Moreover, some synergic effects were also observed. The field trails indicated that the corrected efficacies of all treatments were above 75% （75.62-87.85%）. The efficacy of combined treatment （difenoconazole 100 mg/L ＋ prochloraz 400 mg/L） was above 85%, which was significantly higher than that of other treatments. [Conclusions] The combined treatment containing difenoconazole and prochloraz possessed better control effects compared with individual insecticides, and such a combination was suitable for preventing anthracnose in D. candidum caused by C. gloeosporioides.