噻虫嗪对丽蚜小蜂寄生烟粉虱的影响

为了明确噻虫嗪对烟粉虱天敌昆虫丽蚜小蜂Encarsia formosa的影响,在室内模拟田间噻虫嗪灌根和叶面喷雾2种施药方式,研究了施药后丽蚜小蜂的直接死亡率及其寄生Q型烟粉虱的生物学参数。结果表明,经噻虫嗪叶面喷雾后,丽蚜小蜂的死亡率高达98.10%,显著高于其它处理,丽蚜小蜂对烟粉虱若虫的寄生率为5.26%,显著低于其它处理;与清水对照相比,经噻虫嗪处理后丽蚜小蜂对烟粉虱的致死率降低,且叶面喷雾处理大于灌根处理;噻虫嗪灌根和叶面喷雾处理对丽蚜小蜂的羽化率和发育历期均无显著影响,但均能显著缩短丽蚜小蜂成虫的寿命。研究表明,噻虫嗪灌根施药方式对丽蚜小蜂的死亡率及寄生率影响较小,可将噻虫嗪灌根施药方式与释放丽蚜小蜂相结合以防治烟粉虱。     

噻虫嗪种衣剂对草地贪夜蛾生命参数的影响

为明确噻虫嗪种衣剂对草地贪夜蛾Spodoptera frugiperda生长发育和繁殖能力的影响,通过室内种群生命表方法分析不同浓度0.5、1、2、4 mL/kg噻虫嗪处理下草地贪夜蛾种群的生命参数。结果表明:草地贪夜蛾幼虫历期和世代周期随着噻虫嗪浓度的增加而延长,1 mL/kg浓度处理下雄成虫寿命为15.40 d,平均单雌产卵量为888.04粒,均显著高于对照和其它浓度处理,而雌成虫产卵前期为3.88 d,显著短于对照和其它浓度处理。噻虫嗪浓度对草地贪夜蛾蛹期和雌成虫寿命无显著影响,但对蛹重有一定影响,0.5、1 mL/kg浓度处理的蛹重与对照无显著差异,2、4 mL/kg浓度处理的蛹重随浓度增加而显著降低;幼虫存活率、化蛹率和羽化率随着噻虫嗪浓度的增加而降低。0.5、1 mL/kg浓度处理后雌成虫繁殖力和最高繁殖值较对照偏高,2、4 mL/kg浓度处理则相反。0.5、1 mL/kg浓度处理的草地贪夜蛾平均世代周期、净增殖率、内禀增长率、周限增长率均与对照无显著差异;2、4 mL/kg浓度处理的平均世代周期随着噻虫嗪浓度的增加而显著增加,净增殖率、内禀增长率、周限增长率则随着浓度的增加而显著下降。表明噻虫嗪种衣剂处理在较高浓度时对当代草地贪夜蛾种群有一定的抑制作用,随着药剂在植株体内的降解,这种抑制作用逐渐降低,低浓度处理对成虫生殖能力具有一定的促进作用。     

桃蚜对有机磷和氨基甲酸酯抗性机制研究

1986—1990年对桃蚜(Myzus persicae Sulz.)抗药性的系统研究结果表明,北京地区桃蚜对乐果的抗性最高为230倍,氧乐果为185倍,马拉硫磷为32倍,喹硫磷为19倍,倍硫磷为123倍,马拉氧磷为100倍,毒死蜱为39倍,抗蚜威为245倍,灭多威为39倍,呋喃丹为84倍,对西维因没有产生明显抗性。TPP 与氧乐果、乐果混用分别增效3.2倍和12.1倍;异稻瘟净与倍硫磷、马拉硫磷混用,共毒系数分别为236和234。增效醚(Pb)使乐果和氧乐果分别增效7.1倍和6.0倍。说明桃蚜的抗药性与羧酸酯酶和多功能氧化酶(MFO)有关。在敏感种群中,β-NA 羧酸酯酶活性大于0.5(OD_(555)值/蚜·15分钟)的个体仅占1%,而在抗性种群中,这种类型的个体占78%—98%。不同抗性水平的桃蚜种群,乙酰胆碱酯酶对抑制剂敏感度的分布与其抗性水平具有明显的相关性,马拉氧磷、抗蚜威对乙酰胆碱酯酶的抑制中浓度(I_(50)),抗性种群是敏感种群的20倍和150倍。北京地区桃蚜的抗药性与磷酸酯酶和 GSH—S-转移酶没有明显的关系。     

噻虫嗪及其代谢物噻虫胺在冬枣中的残留动态研究

采用液相色谱质谱法研究了噻虫嗪及其代谢物噻虫胺在冬枣中的分析方法及动态残留量。本方法噻虫嗪和噻虫胺在冬枣中的平均回收率分别为91.4%~102.3%和90.5%~102.8%,相对标准偏差分别为1.3%~3.8%和2.8%~4.7%,样品的方法定量限为0.01mg/kg,表明所建立的方法具有良好的准确度。将所建立的方法用于冬枣田间条件下噻虫嗪及噻虫胺的残留动态分析,为农药施用技术的安全性提供可靠评价。     

噻虫嗪及其代谢物噻虫胺在枸杞中的残留消解及膳食摄入风险评估

为分析50%噻虫嗪水分散粒剂在枸杞上的残留情况, 评估其残留量对人体的膳食摄入风险, 建立了噻虫嗪及其代谢物噻虫胺在枸杞上的高效液相色谱-串联质谱检测方法, 分析枸杞中农药的最终残留量, 估算农药慢性摄入风险。结果表明, 在0.01~1.0 mg/L的范围内, 2种农药的线性关系良好, 相关系数大于0.999。在0.01、0.1、1.0 mg/kg 3个添加水平下, 平均回收率为80.7%~106.6%, 相对标准偏差为1.4%~4.6%。储藏稳定性试验结果表明, 冷冻条件下储藏11个月, 噻虫嗪和噻虫胺在枸杞中均稳定。中国居民摄入噻虫嗪和噻虫胺的慢性暴露风险分别为16.6%和3.8%, 远低于100%, 慢性膳食暴露风险低。     

噻虫嗪及其代谢物噻虫胺在茶树菇及其菌棒上的残留及消解动态

为研究噻虫嗪及其代谢物在茶树菇及其菌棒上的消解动态及最终残留量规律,以30%噻虫嗪悬浮剂为供药试剂开展田间试验,建立液相色谱-串联质谱残留检测分析方法,对茶树菇及其菌棒上噻虫嗪及其代谢物噻虫胺的消解动态规律和最终残留进行检测分析。结果表明：在0.01～0.5 mg/L和0.004～0.2 mg/L线性范围内,噻虫嗪及其代谢物噻虫胺的质量浓度与其峰面积间线性关系良好,R²均>0.999,在茶树菇和菌棒中的平均回收率为96%～103%,相对标准偏差为0.7%～4.2%。噻虫嗪在茶树菇上消解过程符合一级动力学模型,半衰期分别为1.77 d。用药后3～10 d,噻虫嗪在菌棒中的残留量主要集中在上段,噻虫胺在茶树菇和菌棒上的残留量均<定量限。30%噻虫嗪悬浮剂以有效成分0.009、 0.013 5 g a.i./m²的剂量施药2～3次,用药10 d后噻虫嗪在茶树菇中的残留量近似于欧盟规定噻虫嗪在真菌上的最大允许残留限量0.01 mg/kg。     

氯虫·噻虫嗪在芥蓝中的残留消解动态研究

对氯虫·噻虫嗪SC(300 g/L)在芥蓝中的残留消解动态进行了研究。结果表明,按照推荐剂量的2倍剂量(60mL/667m2)施药,氯虫苯甲酰胺和噻虫嗪在芥蓝中的原始沉积量分别为3.648 0 mg/kg和8.347 7 mg/kg,残留消解方程分别为Ct=4.198e-0.273 t和Ct=7.589e-0.424 6 t,半衰期分别为2.5 d和1.6 d。施药后21 d氯虫·噻虫嗪残留量降解至0.01 mg/kg以下。     

不同施药方式下噻虫嗪和噻虫胺对韭菜迟眼蕈蚊的防治效果

为提高田间韭菜养根期噻虫嗪和噻虫胺对韭菜迟眼蕈蚊的防治效果,通过喷淋和灌溉施药方式研究了噻虫嗪和噻虫胺在土壤中的分布情况、喷淋施药后在田间的移动性以及对韭蛆的防治效果和对韭菜生长指标的影响。结果表明,喷淋施药比灌溉施药利于药液到达地下靶标位置,且药剂浓度随着土壤深度增加而减小;喷淋施药后药剂在韭菜根部土壤中的浓度明显高于其在行间土壤中的浓度;施药后120 d与7 d相比,药剂在垂直方向上出现下移,在水平方向上随水流方向移动;12 kg(a.i.)/hm2噻虫嗪和3、6 kg(a.i.)/hm2噻虫胺喷淋施药后对韭菜迟眼蕈蚊的防治效果在80%以上,且均可维持120 d以上,并对韭菜生长有促进作用。因此,利用噻虫嗪和噻虫胺喷淋施药防治韭菜养根期的韭菜迟眼蕈蚊是可行的。     

0.15%噻虫嗪药肥混剂对甘蔗害虫的防控效果

采用0.15%噻虫嗪药肥混剂对甘蔗害虫进行防效试验。结果显示:0.15%噻虫嗪药肥在甘蔗新种时,直接撒施于甘蔗植沟中,对甘蔗螟虫和蓟马均有较好的防治效果,用于防治螟虫时使用剂量与防治效果之间存在正相关,即防治效果随使用剂量的增加而提高,而用于防治蓟马时不同的使用剂量防效差异不大。0.15%噻虫嗪药肥在甘蔗上推荐用量为600~900 ai g/ha。     

噻虫嗪种子处理对冬小麦黑森瘿蚊的防治效果

黑森瘿蚊(Mayetiola destructor(Say))是我国重要的检疫性害虫,近年在新疆博尔塔拉州局部暴发。田间试验了30%噻虫嗪WS拌种处理新冬18号小麦种子对黑森瘿蚊的防效及其对出苗率和产量的影响。结果表明,每100 kg种子分别用30%噻虫嗪WS 100 m L、200 m L、300 m L 3种剂量拌种处理后对黑森瘿蚊的防效分别为77.99%~78.35%、81.79%~100%、92.23%~100%;拌种处理可显著提高小麦产量,且不会降低田间出苗率,300 m L/100 kg种子处理可显著提高出苗率。建议生产中采用30%噻虫嗪WS 300 m L/100 kg种子进行处理防治黑森瘿蚊。     

桃蚜高效氯氰菊酯抗药性与乙酰胆碱酯酶的关系

于室内对桃蚜进行高效氯氰菊酯抗药性筛选,选育至10代后抗性倍数增长到49.9倍。生化分析表明,抗性品系乙酰胆碱酯酶(AChE)活性均显著高于敏感品系。比较两个品系乙酰胆碱酶活性个体频率分布发现,更多的桃蚜个体向酶活性高的区域分布。酶动力学测定结果显示,抗性桃蚜酯酶对底物的Vmax、Km显著大于敏感品系。     

Comparative analysis of neonicotinoid binding to insect membranes: II. An unusual high affinity site for [3H]thiamethoxam in Myzus persicae and Aphis craccivora

Neonicotinoids represent a class of insect-selective ligands of nicotinic acetylcholine receptors. Imidacloprid, the first commercially used neonicotinoid insecticide, has been studied on neuronal preparations from many insects to date. Here we report first intrinsic binding data of thiamethoxam, using membranes from Myzus persicae Sulzer and Aphis craccivora Koch. In both aphids, specific binding of [3H]thiamethoxam was sensitive to temperature, while the absolute level of non-specific binding was not affected. In M persicae, binding capacity (Bmax) for [3H]thiamethoxam was ca 450 fmol mg(-1) of protein at 22 degrees C and ca 700 fmol mg(-1) of protein at 2 degrees C. The negative effect of increased temperature was reversible and hence not due to some destructive process. The affinity for [3H]thiamethoxam was less affected by temperature: Kd was ca 11 nM at 2 degrees C and ca 15 nM at 22 degrees C. The membranes also lost binding sites for [3H]thiamethoxam during prolonged storage at room temperature, and upon freezing and thawing. In A craccivora, [3H]thiamethoxam was bound with a capacity of ca 1000 fmol mg(-1) protein and an affinity of ca 90 nM, as measured at 2 degrees C. Overall, the in vitro temperature sensitivity of [3H]thiamethoxam binding was in obvious contrast to the behaviour of [3H]imidacloprid studied in parallel. Moreover, the binding of [3H]thiamethoxam was inhibited by imidacloprid in a non-competitive mode, as shown with M persicae. In our view, these differences demonstrate that thiamethoxam and imidacloprid, which represent different structural sub-classes of neonicotinoids, do not share the same binding site or mode. This holds also for other neonicotinoids, as we report in a companion article.     

兰州市桃蚜抗药性监测及治理对策研究

以甘肃省宕昌县桃蚜为敏感种群,测定了兰州、永登等地桃蚜对6种杀虫剂抗药性。结果表明兰州市安宁区桃蚜对溴氰菊酯已产生低水平抗性(6.84倍),对氰戊菊酯则处于耐药力增高或敏感性降低阶段,对灭多威、敌敌畏、氧乐果和乐果已显示出早期抗性;永登县桃蚜对溴氰菊酯和氰戊菊酯处于敏感性降低阶段,对灭多威、敌敌畏、氧乐果和乐果仍属敏感阶段;皋兰县和榆中县桃蚜对上述6种杀虫剂则处于敏感阶段。用酶抑制剂进行增效作用测定结果显示,兰州地区桃蚜的抗药性与羧酸酯酶和多功能氧化酶有关。针对兰州市桃蚜的抗药性现状和抗性机制,提出了以建立抗性监测制度、合理用药为主的抗性治理对策。     

桃蚜敏感种群的筛选及其抗药性演化的研究

采用微量毛细管点滴法筛选出比河北廊坊桃蚜相对敏感种群更为敏感的甘肃宕昌桃蚜种群,建立了18种杀虫剂对桃蚜敏感种群的毒力基线,可作为今后国内各地监测桃蚜抗药性水平的敏感基线。用氧乐果、氰戊菊酯及其氧乐果+氰戊菊酯对桃蚜敏感种群进行抗性选育,汰选20次时桃蚜对混剂氧乐果+氰戊菊酯只产生4.85倍的抗药性,比氧乐果单剂(7.39倍)抗性发展速度幔,尤其比氰戊菊酯单剂(87.21倍)更慢,表明桃蚜易对菊酯类药剂产生抗药性,混剂可以延缓产生抗药性。     

Correlated responses to neonicotinoid insecticides in clones of the peach-potato aphid, Myzus persicae (Hemiptera: Aphididae)

BACKGROUND: Although there are still no confirmed reports of strong resistance to neonicotinoid insecticides in aphids, the peach-potato aphid (Myzus persicae Sulzer) shows variation in response, with some clones exhibiting up to tenfold resistance to imidacloprid. Five clones varying in response to imidacloprid were tested with four other neonicotinoid molecules to investigate the extent of cross-resistance.RESULTS: All four compounds-thiamethoxam, thiacloprid, clothianidin and dinotefuran-were cross-resisted, with ED(50) values ranked in the same order as for imidacloprid. Resistance factors ranged up to 11 for imidacloprid, 18 for thiamethoxam, 13 for thiacloprid, 100 for clothianidin and 6 for dinotefuran.CONCLUSION: This variation in response does not appear to be sufficient to compromise the field performance of neonicotinoids aimed at controlling aphids. However, it highlights the need for careful vigilance and stewardship in all M. persicae populations, and a need to consider neonicotinoids as a single cross-resisted group for management purposes.     

Uncommon associations in target resistance among French populations of Myzus persicae from oilseed rape crops

Within the framework of a molecular exploration of target resistance in populations of Myzus persicae on oilseed rapes in France, (1) the S431F mutation (coding gene ace2), although previously reckoned to be rare, revealed to be frequent, (2) M918L (phenotypically characterised) and L932F (both on para) were found for the first time in M. persicae, and (3) a linkage was revealed between M918L and S431F. While until recently populations developing on French oilseed rapes were dominated by genotypes possessing pyrethroid target resistance and esterase overproduction, to date a different type of dominating genotype, equipped with carbamate and pyrethroid target resistance, seems to be invading such fields.