【目的】棉花立枯病是影响新疆棉花产量和质量的重要病害,筛选高效防病药剂,有效控制该病的发生为害。【方法】采用分属不同融合群的立枯丝核菌菌株作为供试菌,通过抑菌圈实验﹑毒力测定和田间防效验证,对多种立枯病防病用药进行比较和筛选。【结果】12种药剂对棉花立枯丝核菌主要融合群(AG4)的抑制作用有明显差异,12种药剂中,甲基立枯磷﹑GJJ﹑ BL﹑卫福﹑代森锰锌﹑百菌清等8种药剂抑菌作用较好；9种农药对立枯丝核菌的毒力大小差异显著,同一种农药对不同融合群的毒力亦有一定差异,4种农药中对立枯丝核菌总的毒力及对棉花立枯病菌主要融合群的毒力较大,EC50﹤3 mg∕L 的药剂有 GJJ﹑甲基立枯磷﹑BL﹑卫福；4种药剂的田间防病效果在大田最高防效达65％以上。【结论】12种药剂中 4种药剂(GJJ﹑甲基立枯磷﹑卫福﹑BL)对棉花立枯病有较好的防效；GJJ﹑甲基立枯磷对棉花立枯病表现出高效防病作用。%Objective]Cotton damping —off is an important disease affecting the yield and quality of cot_ton in Xinjiang.This project aims to efficiently screen prophylactic fungicide which might effectively protect the disease from occurrence and damage.[Method] The strains of Rhizoctonia belonging to different anasto_mosis groups were taken as the test bacteria,and through inhibition zone test,toxicity test and checking in the fields,a variety of pesticide that prevent Rhizoctonia solani KÜhn was compared and contrasted before making final choice.[Result]The inhibition zone test indicated that: among the 12 kinds of fungicides,the inhibitory effect which could fight against the major anastomosis group (AG4) of cotton Rhizoctonia solani had significant differences;Among them,8 kinds of fungicide such as tolclofos —methyl GJJ,BL and Thiram ﹠Carboxin etc. had better inhibitory effect.Toxicity test results showed that: virulence size of nine kinds of fungicides against cotton Rhizoctonia solani had significant differences.The virulence of the same fungicide against different anas_tomosis groups also had significant differences.The four kinds of fungicides had better toxicity against all Rhi_zoctonia and major anastomosis group (AG4) of cotton Rhizoctonia solani.The EC50 of four kinds of fungi_cides are less than 3 mg ∕L,including GJJ,Tolclofos —methyl,BL and Thiram ﹠Carboxin.Field effect verifi_cation showed that four kinds of fungicide maximum control efficiency was up to 80%.[Conclusion] The four kinds of fungicide (GJJ,tolclofos,Weifu and BL) of the twelve kinds were highly efficient for controlling the cotton damping —off.
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