10种杀菌剂对番茄晚疫病菌的室内毒力测定

采用菌丝生长抑制法测定了烯酰吗啉、嘧霉胺等10种杀菌剂对番茄晚疫病菌(Phytophthora infestans)的室内活性。结果表明:50%烯酰吗啉可湿性粉剂防效最高,EC50和EC90值分别为1.81μg/ml和10.63μg/ml,回归方程为Y=4.57272+1.66462X;其次是250 g/L嘧菌酯悬浮剂和75%百菌清可湿性粉剂,EC50和EC90值分别为2.70、2.54μg/ml和1.08×107、10708.95μg/ml,但两种药剂随着浓度的增加防效增加不显著,EC90的值都较高;58%甲霜.锰锌可湿性粉剂和70%代森联水分散粒剂的防效相对较高,EC50低于10μg/ml,分别为6.09、8.75μg/ml,EC90分别为69.98、60.19μg/ml,回归方程分别为Y=4.05225+1.20831X和Y=3.55894+1.52997X。25%多菌灵可湿性粉剂对病原菌菌丝也有抑制作用,各个处理菌丝扩展面积大,但菌丝生长稀薄,长势弱。

Toxicity Test of Ten Fungicides to Phytophthora infestans in Laboratory

The toxicity of 10 fungicides against Phytophthora infestans was detected by the method of mycelium growth inhibition.The results showed that 50% dimethomorph WP had the best control effect with EC50 and EC90 as 1.81 μg/ml and 10.63 μg/ml respectively,and the regression equation was Y=4.57272+1.66462X.The followed fungicides were 250 g/L azoxystrobin SC and 75% chlorothalonil WP with the EC50 as 2.70 μg/ml and 2.54 μg/ml,and the EC90 as 1.08×107 μg/ml and 10 708.95 μg/ml respectively.But with the increase of dosage,the control effects of the two fungicides did not increase significantly,and their EC90 value were higher.The control effects of 58% metalaxyl·mancozeb WP and 70% metiram WDP were relatively higher with the EC50 value as 6.09 μg/ml and 8.75 μg/ml,and the EC90 as 69.98 μg/ml and 60.19 μg/ml respectively.Their regression equations were Y=4.05225+1.20831X and Y=3.55894+1.52997X respectively.25% carbendazim WP also could inhibit Phytophthora infestans.Although the extended area of hypha was great,the hypha grew weak and thin.