防治糜子丝黑穗病的杀菌剂筛选及田间防治效果研究

为筛选防治糜子丝黑穗病的高效药剂,采用琼脂平板孢子萌芽法测定了6种杀菌剂对糜子丝黑穗病菌的室内毒力,并通过两年田间小区试验评价了杀菌剂对糜子丝黑穗病的药效及糜子植株生长的影响。室内毒力测定结果表明,戊唑醇对丝黑穗病菌的毒力最强,EC50值为0.1127μg/mL,其次为烯唑醇、苯醚甲环唑、甲基硫菌灵和多菌灵,EC50值分别为1.0634,6.1775,12.4969和54.4021μg/mL,福美双的毒力最弱,EC50值为1169.6448μg/mL。药剂处理与对照相比,发芽率均有显著降低,随浓度的增高,种子活力下降,其中烯唑醇对种子萌发抑制作用最大,发芽率和发芽势均最小。田间药效试验结果与室内毒力测定结果一致,戊唑醇防效最好,其次为烯唑醇、甲基硫菌灵、多菌灵,苯醚甲环唑仅在浓度高时防效较好,福美双防治效果最差。植株生长影响评价结果表明,多菌灵显著降低主茎倒二叶面积、主茎倒三叶面积、叶干重和分蘖数。与对照相比,各药剂处理下的单株粒重均有不同程度的减少,但产量均增加,其中戊唑醇处理下的产量两年均最高,而福美双在2014年没有显著增产效果。因此,在6种供试药剂中,戊唑醇能以最低浓度获得最好的防治效果,可在实际生产中推广利用。

Efficacy of fungicides for control of head smut (Sporisorium destruens)in broomcorn millet

Six fungicides potentially useful for control head smut in broomcorn millet (Panicum miliaceum ) were assessed for toxicity and field efficacy against Sporisorium destruens by assessing teliospore germination on agar medium in a laboratory and the growth of broomcorn millet in the field over two seasons.The results of laboratory toxicity tests showed that tebuconazole exhibited the greatest inhibition of S .destruens ,with the EC50 (median effective concentration)value of 0.1127 μg/mL,followed by diniconazole,difenoconazole,thio-phanate-methyl and carbendazim with the EC50 values of 1.0634,6.1775,12.4969 and 54.4021 μg/mL,re-spectively.Thiram showed the lowest toxicity with the EC50 value of 1169.6448 μg/mL.Compared with the control (no fungicide),fungicide treatments significantly decreased the germination rate and vigor of broom-corn millet seeds.Diniconazole reduced germination and vigor the most.The results of field efficacy trials were similar;tebuconazole had the best control efficacy,followed by diniconazole,thiophanate-methyl and carbenda-zim.The control efficacy of difenoconazole was good only at high concentration.Thiram had the poorest con-trol efficacy.Carbendazim significantly reduced the area of the second and the third leaf,dry weight of leaves and the number of tillers.Compared with the control,all fungicide treatments reduced grain weight but in-creased the grain yield.Broomcorn millet yields following tebuconazole application were the highest in both years,while thiram didn’t significantly increase yield in 2014.In summary,tebuconazole produced the best control efficacy at the lowest application rate and could be used for broomcorn millet production.