新烟碱类杀虫剂秋季施药防治拱棚菜田韭菜迟眼蕈蚊

Applying Neonicotinoid Insecticides in Autumn to Control Bradysia odoriphaga in Plastic-tunnel Cultivations

为明确新烟碱类杀虫剂秋季施药对设施韭菜田韭菜迟眼蕈蚊Bradysia odoriphaga的控制作用,采用韭菜行内喷淋施药方式比较了噻虫胺、噻虫嗪、吡虫啉和辛硫磷对韭菜迟眼蕈蚊幼虫和成虫的防治效果和对韭菜产量的影响,并测定了韭菜中的农药残留量。结果表明噻虫胺和吡虫啉1.5、3 kg(有效成分)/hm^2,噻虫嗪3、6 kg(有效成分)/hm^2处理对韭菜迟眼蕈蚊幼虫药后82 d的防效多数高于80%,显著高于辛硫磷6 kg(有效成分)/hm^2处理。药后145 d各处理防效普遍降低,其中噻虫胺1.5、3 kg(有效成分)/hm^2防效为69.23%和75.06%,噻虫嗪3、6 kg(有效成分)/hm^2防效为69.22%和71.39%,吡虫啉1.5、3 kg(有效成分)/hm^2防效为58.45%和69.23%,对照药剂辛硫磷6 kg(有效成分)/hm^2防效仅为31.77%。各药剂处理对韭菜迟眼蕈蚊成虫的防效与幼虫相似。噻虫胺、噻虫嗪和吡虫啉处理韭菜鲜重显著高于辛硫磷和空白对照处理。收获期,各药剂处理韭菜中药剂残留量均<0.01 mg/kg。新烟碱类杀虫剂秋季施药防治韭菜迟眼蕈蚊是可行的,噻虫胺3 kg(有效成分)/hm^2的防效较高且残留风险低。

To determine the efficacy of clothianidin, thiamethoxam, imidacloprid and phoxim in controlling Bradysia odoriphaga, the insecticides were drip-drenched in the line of leek in autumn in plastic-ttmnels which cultivate Chinese chive. Their effects on the fresh weight of Chinese chive and relevant residues in the Chinese chive were also investigated. The results showed that clothianidin and imidacloprid at the rates of 1.5 and 3 kg a.i./ha, thiamethoxam at the rates of 3 and 6 kg a.i,/ha can reduce the abundance of B. odoriphaga larvae approximately by 80% on the 82th day after treatment （DAT）, which was significantly higher than that of phoxim 6 kg a.i./ha. 145 DAT, all the control effects dramatically decreased. The efficacies of clothianidin and imidaeloprid at the rates of 1.5 and 3 kg a.i./ha were 69.23 and 75.06%, and 69.22 and 71.39%, whereas that of thiamethoxam at the rates of 3 and 6 kg a.i./ha were 58.45 and 69.23%, respectively. However, that of the reference insecticide phoxim was only 31.77%. The efficacy of each concentration of insecticides in controlling B. Odoriphaga adults was similar to that of the larvae. The fresh weights of Chinese chive for clothianidin, thiamethoxam and im.idacloprid treatments were all significantly higher than that of phoxim and untreated control. The residues in Chinese chive of all treatments were lower than 0.01 mg/kg when harvest. In conclusion, applying neonicotinoid insecticides in autumn was feasible to control B. odoriphaga although different treatments differed in efficacy. Applying clothianidin at the rate of 3 kg a.i./ha was recommended owing to its low residual risk and favorable efficacy.