嘧菌酯对扁豆纹枯病的物理作用方式及其生物动力学特性

以多菌灵和福美双为对照药剂,测定了嘧菌酯对立枯丝核菌Rhizoctonia solani的抑制活性,并用离体叶片法测定了嘧菌酯对该病原菌引起的扁豆纹枯病的物理作用方式及其生物动力学特性。嘧菌酯、多菌灵和福美双对立枯丝核菌菌丝生长的EC50值分别为0.072 4、1.134 4和1.202 6 μg/mL。施药后立即接种, 250 μg /mL嘧菌酯、500 μg /mL多菌灵和1 000 μg /mL福美双对扁豆纹枯病的保护效果分别为95.61％、99.88％和81.45％;施药3 d后再接种,嘧菌酯、多菌灵和福美双对扁豆纹枯病的保护效果分别为92.27％、100％和46.96％;接种36 h后再施药,3种药剂对扁豆纹枯病的治疗效果分别为90.40％、95.75％和61.94％。表明嘧菌酯对扁豆纹枯病具有很好的保护作用、持效性和治疗作用。在叶片基部施药后在顶部接种,嘧菌酯、多菌灵和福美双对扁豆纹枯病的防治效果分别为87.81％、42.09％和7.24％;在叶片背面施药后在正面接种,3种药剂对扁豆纹枯病的保护效果分别为87.30％、37.00％和16.15％。表明嘧菌酯在扁豆叶片中具有很好的木质部输导和跨层转移活性。

Physical Modes of Action of Azoxystrobin and Its Biokinetics for Controlling Haricot Bean Leaf Blight Caused by Rhizoctonia solani

Compared with carbendazim and thiram,the inhibitory activity of azoxystrobin to mycelial growth of Rhizoctonia solani,the pathogen of rice sheath blight,was tested in vitro,and the physical modes of action of azoxystrobin and its biokinetic properties for controlling haricot bean leaf blight caused by R.solani were evaluated by detached leaf methods.The EC50 values of azoxystrobin, carbendazim and thiram against mycelial growth of R.solani on PDA were 0.072 4 μg /mL,1.134 4 μg /mL and 1.202 6 μg /mL,respectively.When the pathogen was inoculated immediately after fungicide application,the protective efficacy of azoxystrobin (250 μg/mL),carbendazim (500 μg /mL) and thiram (1 000 μg /mL) for controlling haricot bean leaf blight were 95.61%,99.88% and 81.45%, respectively; when the pathogen was inoculated 3 days after fungicide application,the protective efficacy of azoxystrobin,carbendazim and thiram were 92.27%,100% and 46.96%,respectively; and when the fungicides were applied 36 hours after inoculation the curative efficacy of azoxystrobin,carbendazim and thiram were 90.40%,95.75% and 61.94%,respectively.These results indicated that azoxystrobin had not only very good protection and retention but also excellent curative action.When the fungicides were applied on the leaf base but the pathogen was inoculated on the untreated leaf tip,the protective efficacy of azoxystrobin,carbendazim and thiram for controlling haricot bean leaf blight were 87.81%,42.09% and 7.24%,respectively; when the fungicides were applied on the abaxial (lower) leaf surface but the pathogen was inoculated on the untreated adaxial (upper) surface,the protective efficacy of azoxystrobin,carbendazim and thiram were 87.30%,37.00% and 16.15%,respectively.It demonstrated that azoxystrobin had both excellent xylem systemic translocation and translaminar movement in haricot bean leaves.