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.     

噻虫啉、高效氯氰菊脂防治竹卵圆蝽试验

对2.0％噻虫啉触破式微胶囊和2.5％高效氯氟氰菊酯对竹卵圆蝽的毒杀效果进行试验,结果表明:2.0％噻虫啉触破式微胶囊水悬剂200倍液和2.5％高效氯氟氰菊酯触破式微胶囊水悬剂200倍液对竹卵圆蝽的毒杀活性均较高,校正死亡率分别达到88.9％和92.8％;施药2、7、30d后虫口密度最高分别下降了94.3％和93.0％;大田试验结果表明,施药30d后虫口密度显著下降,下降率分别达90.0％和91.9％.     

噻虫啉微胶囊粉剂防治松褐天牛药效试验

通过不同浓度的噻虫啉微胶囊粉剂防治松褐天牛药效试验,结果表明,噻虫啉微胶囊粉剂对松褐天牛有很好的防治效果.0.5％、1％、2％噻虫啉微胶囊粉剂（7.5 kg/hm^2）防治松褐天牛,药后35 d效果分别为64.26％、86.60％、86.94％,1％噻虫啉微胶囊粉剂对松褐天牛防效远高于0.5％噻虫啉微胶囊粉剂的防治效果,与2％噻虫啉微胶囊粉剂的防治效果差异不显著,建议用1％噻虫啉微胶囊粉剂7.5 kg/hm2防治松褐天牛.     

Pyrethroid resistance and thiacloprid baseline susceptibility of European populations of Meligethes aeneus (Coleoptera: Nitidulidae) collected in winter oilseed rape

BACKGROUND: Pollen beetle, Meligethes aeneus F. (Coleoptera: Nitidulidae), is a major pest in European winter oilseed rape. Recently, control failures with pyrethroid insecticides commonly used to control this pest have been reported in many European countries. For resistance management purposes, the neonicotinoid insecticide thiacloprid was widely introduced as a new mode of action for pollen beetle control. RESULTS: A number of pollen beetle populations collected in Germany, France, Austria, Great Britain, Sweden, Denmark, Finland, Poland, Czech Republic and Ukraine were tested for pyrethroid resistance using lambda‐cyhalothrin‐coated glass vials (adult vial test). Most of the populations tested exhibited substantial levels of resistance to lambda‐cyhalothrin, and resistance ratios ranged from < 10 to > 2000. A similar resistance monitoring bioassay for the neonicotinoid insecticide thiacloprid was developed and validated by assessing baseline susceptibility data for 88 European pollen beetle populations. A variation of less than fivefold in response to thiacloprid was detected. The thiacloprid adult vial bioassay is based on glass vials coated with an oil‐dispersion‐based formulation of thiacloprid, resulting in a much better bioavailability compared with technical material. Analytical measurements revealed a > 56 and 28 day stability of thiacloprid and lambda‐cyhalothrin in coated glass vials at room temperature, respectively. No cross‐resistance between thiacloprid and lambda‐cyhalothrin based on log‐dose probit–mortality data was detected. CONCLUSION: Pyrethroid resistance in many European populations of M. aeneus was confirmed, whereas all populations are susceptible to thiacloprid when tested in a newly designed and validated monitoring bioassay based on glass vials coated with oil‐dispersion‐formulated thiacloprid. Based on the homogeneous results, it is concluded that thiacloprid could be an important chemical tool for pollen beetle resistance management strategies in European winter oilseed rape. Copyright © 2011 Society of Chemical Industry     

噻虫啉拌种对玉米幼苗生理生化指标的影响

旨在明确噻虫啉悬浮种衣剂拌种对玉米幼苗生长、玉米幼苗叶片保护酶和根系活力的影响。通过室内盆栽法,以噻虫啉浓度为2、4、5、6、8 g/kg(种子)拌种,测定玉米幼苗三叶一心期的生长指标(株高、根长、茎粗、须根数和鲜重)、根系活力和叶片保护酶。结果表明:噻虫啉拌种能显著提高玉米幼苗的各生长指标、叶片保护酶活性和根系活力,随着噻虫啉浓度的增加呈现出先升高后降低的趋势,且浓度为4~5 g/kg(种子)拌种处理大于吡虫啉处理,8 g/kg(种子)处理对玉米植株的生长已经有了轻微的抑制作用,但叶片保护酶活性和根系活力值仍高于空白对照处理。研究结果表明:合适剂量的噻虫啉拌种处理可以显著促进玉米幼苗的生长。     

Effect of seven new orchard pesticides on Galendromus occidentalis in laboratory studies

BACKGROUND: Biological control of phytophagous mites in orchards requires that pesticides used to manage other arthropod pests or diseases are harmless to predacious mites, as these are essential to keep phytophagous mites at non‐injurious population levels. This study evaluates the possible toxic attributes of acetamiprid, imidacloprid, thiacloprid, thiamethoxam, spirodiclofen, spinosad and methoxyfenoxide currently used in western Canadian orchards. RESULTS: None of these pesticides has any ovicidal properties against Galendromus occidentalis (Nesbitt). Imidacloprid and acetamiprid were highly toxic to the adults and reduced fecundity significantly. Thiamethoxam and spirodiclofen were non‐toxic to adults, but they slightly reduced fecundity. Thiacloprid, spinosad and methoxyfenoxide were harmless to adults and had no effect on fecundity. All compounds showed some repellence at 24 h intervals for 72 h. CONCLUSIONS: Imidacloprid and acetamiprid are incompatible with IPM programs because they are toxic to adults and negatively affect fecundity. Thiamethoxam and spirodiclofen need further field evaluation to determine if they are compatible with IPM programs because they slightly reduced fecundity. Thiacloprid, spinosad and methoxyfenoxide are harmless to adults, but they are slightly repellent. Therefore, with the exception of imidacloprid and acetamiprid, all these compounds should be field tested for compatibility in an IPM program. © Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture and Agri‐Food Canada. Published by John Wiley & Sons, Ltd