吡虫啉对枸杞土壤微生物群落功能多样性的影响

采用Biolog方法研究吡虫啉对枸杞土壤微生物群落功能多样性的影响。结果表明,吡虫啉3 000倍稀释液在施用后1d对土壤微生物群落功能多样性影响显著;在施用后3d对土壤微生物群落功能多样性的影响仍然十分明显,施用后5d开始减弱;即使极低浓度30 000倍稀释液的吡虫啉对枸杞土壤微生物群落多样性仍然会产生影响。施用吡虫啉后不同时间对枸杞土壤微生物群落功能多样性的影响大小为:施用后第1天第3天第5天第7天。施用吡虫啉后物种数量呈现增加趋势,个体数减少,Simpson指数无变化,Shannon指数、均匀度和Brillouin降低,未施药土壤和30 000倍稀释液处理的土壤McIntosh指数相同,3 000倍稀释液处理的McIntosh指数较低。     

Two cytochrome P450 genes are involved in imidacloprid resistance in field populations of the whitefly, Bemisia tabaci, in China

The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae), is an invasive and damaging pest of field crops worldwide. The neonicotinoid insecticide imidacloprid has been widely used to control this pest. We assessed the species composition (B vs. Q), imidacloprid resistance, and association between imidacloprid resistance and the expression of five P450 genes for 14–17 B. tabaci populations in 12 provinces in China. Fifteen of 17 populations contained only B. tabaci Q, and two populations contained both B and Q. Seven of 17 populations exhibited moderate to high resistance to imidacloprid, and eight populations exhibited low resistance to imidacloprid, compared with the most susceptible field WHHB population. In a study of 14 of the populations, resistance level was correlated with the expression of the P450 genes CYP6CM1 and CYP4C64 but not with the expression of CYP6CX1, CYP6CX4, or CYP6DZ7. This study indicates that B. tabaci Q has a wider distribution in China than previously reported. Resistance to imidacloprid in field populations of B. tabaci is associated with the increased expression of two cytochrome P450 genes (CYP6CM1 and CYP4C64).     

菠萝不同喷药期吡虫啉残留量的测定

建立一种测定菠萝果实中吡虫啉残留量的高效液相色谱法.在样品中加入乙腈作为提取溶剂,氯化钠吸水,过混合阳离子交换柱净化,残留物用流动相定容,高效液相色谱二极管检测器测定,外标法定量.结果表明,吡虫啉农药残留较高,且基本上呈现了施药后间隔期越短,农药残留越高的趋势.采前7d吡虫啉农药残留达到0.61 mg/kg,间隔期30 d至7d吡虫啉残留介于0.11～0.61 mg/kg,采前35 d吡虫啉残留量为未检出.吡虫啉的检出限为0.02 mg/kg,平均回收率在89％～102％之间,相对标准偏差小于3％.     

5%吡氯乳油防治棉花蚜虫药效试验

对5％吡氯乳油防治棉蚜的药效进行了研究。结果表明，5％吡氯乳油60ml／亩在施药后1d、3d、7d、14d的防效分别为70．9％、73．2％、70．1％、84．4％，45ml／亩在施药后1d、3d、7d、14d的防效分别为74．3％、68．8％、74．7％、85．8％，30ml／亩在施药后1d、3d、7d、14d的防效分别为70．3％、78．1％、58．4％、70．4％。5％吡氯乳油对棉蚜有较好的防治效果，持效期长达14d以上，建议田间施用剂量为30～45ml／亩。     

啶虫脒及吡虫啉对瓜蚜室内生物测定研究

瓜蚜(棉蚜)的寄主广泛,常常对瓜类、棉花、烟草等蔬菜和经济作物造成严重危害.在温室的瓜类上瓜蚜可常年繁殖危害,以成虫和若虫取食瓜类嫩叶及生长点,使叶片及生长点卷缩,老叶受害后变黄.化学防治瓜蚜是综合治理的主要措施之一,对瓜蚜种群具有很强的抑制作用.用药液浸渍法测定了啶虫脒和吡虫啉对瓜蚜的毒性,结果表明:在10～80mg/kg浓度下吡虫啉的防效54.20%～89.04%,高于啶虫脒35.45%～87.34%;用药24 h后吡虫啉对瓜蚜致死中浓度LC50为9.674mg/L、啶虫脒LC50为14.0685mg/L,吡虫啉对瓜蚜的毒性是啶虫脒的1.45倍.