4种药剂对大豆疫霉菌的抑菌效果及复配防效研究OA

Phytophthora root rot,caused by Phytophthora sojae,is a critical disease threatening soybean production.To effectively control this disease,the mycelial growth rate method was employed to determine the toxicity of metalaxyl-M,oxathiapiprolin,fluazinam,and flumorph against Phytophthora sojae.The EC50 values of the tested fungicides,sorted in ascending order,were as follows:oxathiapiprolin(EC50=0.000 48 μg·mL-1),metalaxyl-M(EC50=0.041 μg·mL-1),flumorph(EC50=0.304 μg·mL-1),and flu-azinam(EC50=0.409 μg·mL-1).Metalaxyl-M and oxathiapiprolin,which exhibited significant bacteriostatic effects,were selected for compounding.The determination results of the toxicity and co-toxicity coefficient(CTC)of the mixture showed that the 7∶10 ratio of the two fungicides yielded the strongest synergistic effect.A pot experiment on disease control was conducted using seed coating with the mixture at this ratio,and the results indicated that the control efficacy of the mixed fungicide was 19.5%-25.6%higher than that of metalaxyl-M used alone.The findings provided important references for the control of soybean Phytophthora root rot and a basis for delaying the development of pathogen resistance caused by the long-term use of a single fungicide.