Studies on Stimulating Effect of Two Selective Insecticides on the Numbers of Laid Egg by Yellow Rice Borer,Tryporyza incertulas (Walker) and Their Effects on Biochemistry of Rice Plants

Buprofezin and imidacloprid are selective insecticides against Homoptera insects. This paper in-vestigated stimulating effect of the two insecticides on the number of laid eggs by yellow rice borer, Tryporyzaincertulas (Walker) of three generations in 2001 -2002. The results showed that the reproductive rate of emer-gence months during the larvae feeding on the rice plants of Xiushui63 treated with the two insecticides was sig-nificantly higher than that of control, indicating that the numbers of laid eggs by the borer was stimulated fol-lowing buprofezin and imidacloprid applications. However, there was no such effect for the larvae feeding onrice variety Zhendao2 which showed moderate resistance to the insect. In addition, the incidence of stimulatingegg laid for the first instar treated with the two insecticides was greater than that for the third instar. Bio-chemical tests showed that oxalic acid concentration declined, and photosynthetic rate of rice leaves followingthe two insecticide applications declined significantly compared to control, whereas reducing sugar concentra-tion increased significantly for all other treatments of two varieties except Xiushui63 treated with buprofezin.The level of glutathione-S-transferase varied with rice variety and insecticide.     

Control of maize pests with imidacloprid seed dressing treatment in Catalonia (NE Iberian Peninsula) under traditional crop conditions

The effects of treating maize seed with imidacloprid to prevent damage by soil pests, aphids, leafhoppers and the first generation of corn borers was evaluated in the field by comparing treated with untreated commercial plots in a 5-year study in Catalonia (NE Iberian Peninsula). The treatment reduced the incidence of cutworms (Agrotis segetum), wireworms (Agriotes lineatus), the first generation of the corn borer Sesamia nonagrioides and leafhoppers (Zyginidia scutellaris). However, treated plots were attacked significantly more by Ostrinia nubilalis. The treatment was effective in reducing aphid densities from maize emergence to mid June. What happened later depended on the relative abundance of aphid species. Rhopalosiphum padi seems to be more sensitive than Metopolophium dirhodum whose population can be enhanced after flowering in plots treated with imidacloprid. The treatment did not avoid aphid alate colonisation and MDMV infection was not prevented. The greater damage on untreated plants caused by wireworms, cutworms and the first generation of S. nonagrioides, and the densities achieved by aphids, was insufficient to produce yield differences between treatments, and only leafhopper damage led to economic damage. Imidacloprid favours the attack of the European corn borer, thus masking the potential increase in yield.     

吡虫啉对链格孢菌生长和繁殖的影响

为了探究杀虫剂吡虫啉是否能直接作用于植物病原菌,通过将其添加至培养基中培养链格孢菌,然后定期测量菌落生长直径、显微观察菌丝生长形态和检测分生孢子的产生,结果显示链格孢菌在添加吡虫啉培养时菌丝生长变慢、菌丝形态纤细,且产孢子较少。这些结果表明吡虫啉对链格孢菌的生长和繁殖均有抑制作用,为其以后用于植物抗病提供一定理论基础。     

Understanding the dynamics of neonicotinoid activity in the management of Bemisia tabaci whiteflies on poinsettias

The relative efficacies of registered label rates for foliar and soil drench treatments of imidacloprid and dinotefuran at preventing the establishment of Bemisia tabaci B biotype whitefly populations on newly infested poinsettia plants were evaluated. Pesticide levels within and on plant leaves were monitored for 10 weeks by ELISA and LC/MS in an effort to better understand the dynamics of neonicotinoid activity against this insect and to estimate insecticide concentrations needed to kill the nymphal and adult stages. While all treatments proved equally effective as a remedial measure for the control of the resident adult populations, thereby accomplishing the objective of foliar contact treatments, the dinotefuran soil drench application was the only treatment that provided multi-generational control of Bemisia populations.     

吡虫啉在宁夏甘草及对应根际土壤中的残留及消解动态研究

【目的】研究吡虫啉在宁夏甘草及对应根际土壤中的残留及消解动态,为甘草规范化种植中吡虫啉安全使用标准的制定提供科学依据。【方法】采用灌根法,将10%吡虫啉可湿性粉剂依推荐剂量设1次和2次施药处理,于施药后不同时间采样,样品经盐酸溶液和甲醇提取及氯化钠溶液和二氯甲烷净化后,采用AgilentHPLC-1100高效液相色谱仪进行检测,对吡虫啉在甘草根部及其根际土壤中的添加回收率、残留动态进行分析。【结果】在设定的色谱条件下,样品的最低检出量为7.49×10-10g,最低检出浓度为3.75μg/kg。标准品不同进样量的测定结果表明,进样量为0.1～10μg/mL时,吡虫啉峰面积与进样量之间有良好的线性关系。甘草中吡虫啉的添加回收率为75.4%～90.4%,相对差标准为7.01%～8.13%,甘草对应根际土壤中吡虫啉的添加回收率为82.7%～93.6%,相对差标准为3.97%～5.11%,符合农药残留分析要求。残留检测结果表明,吡虫啉在甘草及对应根际土壤中的残留消解完全符合一级反应动力学方程式,其半衰期分别为5.44和5.63d;吡虫啉1次施药60d后,甘草中的残留低于最低检测浓度,土壤中的残留仅为0.009mg/kg;2次施药后53d,甘草中的残留量为0.013mg/kg,土壤中的残留量为0.095mg/kg。【结论】依据欧盟制定的"未纳入标准的农药均不得检出"的规定,建议10%吡虫啉可湿性粉剂在甘草上宜采用1次施药,且施药期距采收期的间隔时间不得少于60d。     

Lethal and sublethal effects of buprofezin and imidacloprid on Bemisia tabaci (Hemiptera: Aleyrodidae)

The sweetpotato whitefly, Bemisia tabaci (Gennadius), has become a major threat to agriculture worldwide. The development of insecticide resistance in B. tabaci has necessitated the exploration of new management tactics. The toxicity of imidacloprid and buprofezin to various life stages of B. tabaci was determined in the laboratory. Also, the sublethal effects of both insecticides were studied on demographic and biological parameters of B. tabaci. Both insecticides were very toxic against first stage larvae of the pest with LC₅₀ values of 1.0 and 19.3 ppm for buprofezin and imidacloprid, respectively. Toxicities decreased between successive stages (LC₅₀ values ranging from 1.0 to 2854.0 ppm). The LC₅₀ values of imidacloprid for adult males, females and eggs were 11.8, 71.6 and 151.0 ppm, respectively. Buprofezin had no significant effect on adults and eggs. The sublethal concentration of imidacloprid had no significant effect on demographic and biological parameters of B. tabaci but the maximal value for the mean generation time (T) (18.8 day) was observed in imidacloprid treatment. Buprofezin significantly decreased stable population and biological parameters of B. tabaci except it did not decrease the rate of population increase or the sex ratio of offspring.     

落叶松球蚜病防治试验

对使用溴氰菊酯(敌敌畏)、吡虫啉、氧化乐果和烟雾来防治落叶松球蚜的效果进行了试验,试验以不同稀释倍数进行,结果表明吡虫啉对落叶松球蚜防治效果最好,最佳喷施液为1100倍液;按DDVP:桐油:柴油:=1:1:10配制的油烟剂杀球蚜效果也不错,但是DDVP毒性大,残留期长,不推荐使用。     

两种施药方式下吡虫啉在烟草植株的吸收传导分布研究

[目的]比较喷雾和灌根施药方式下吡虫啉在烟草植株的吸收传导分布规律.[方法]进行温室盆栽试验,采用液相色谱-质谱联用方法测定施药不同时间烟草根、茎、上部叶、中部叶、下部叶中吡虫啉含量.[结果]灌根施药方式下吡虫啉能被烟草根部吸收并转运至植株各个部位,而喷雾施药在烟草叶片上原始沉积量较大,通过内吸作用传导至烟草其他部位的含量较低.[结论]灌根施药在烟草植株内输导分布更加均匀,持效期更好,喷雾施药能较好的作用于叶片部位,速效性更好.     

不同剂型吡虫啉的杀蚜活性比较

拟明确吡虫啉剂型与生物活性的关系,以期获得高效、安全环保及应用范围广的制剂产品,进而为其正确合理使用提供依据。以吡虫啉5种剂型制剂为供试药剂,萝卜蚜、苹果黄蚜、烟蚜和麦长管蚜等4种不同属蚜虫为试虫,分别采用浸虫浸叶和常量喷雾进行室内与田间生物活性比较。室内试验表明,乳油、微乳剂、可溶性液剂、悬浮剂及可湿性粉剂24h的LC50分别为6.15~17.54、7.38~18.44、8.71~20.59、8.62~20.72和20.97~29.49mg/L;田间试验表明,有效成分为30g/hm2时,乳油、微乳剂、悬浮剂及可溶性液剂对苹果黄蚜速效性好、持效期长、防效相当,7d仍在94%以上,而可湿性粉剂防效较差,药后7d为84.01%。可见,悬浮剂与乳油、微乳剂及可溶性液剂的生物活性基本相当,而可湿性粉剂活性最低。然而,从安全、环保及生产成本等综合考虑,推荐在生产应用中应以吡虫啉悬浮剂为主。     

Comparison of the activity of selamectin, imidacloprid and fipronil for the treatment of cats infested experimentally with Ctenocephalides felis felis and Ctenocephalides felis strongylus

Twenty adult, domestic short hair cats were randomly allocated into four groups of five cats and housed in separated cages. Each cat was infested with 25 fleas Ctenocephalides felis felis and 25 Ctenocephalides felis strongylus and 2 days later (day 0) the cats in group 1, 2 and 3 received a spot on application of selamectin, imidacloprid or fipronil, respectively, while the cats in group four were not treated. The cats were combed 48 h later, the fleas were removed, counted and their subspecies were determined. All the cats were reinfested with the same number of the two subspecies of fleas on days 7, 14, 21, 29 and 35. The efficacy of each treatment was calculated 48 h after each infestation. The mean number of fleas on the control cats was 16.4 C. f. felis and 13.4 C. f. strongylus. The three treatments were effective for the first 31 days for C. f. felis and for the full 37 days for C. f. strongylus. Over the first 31 days, the efficacy of selamectin ranged from 89 to 100% and 85 to 100% against C. f. felis and C. f. strongylus, respectively, the efficacy of imidacloprid ranged from 76 to 100% and 92 to 100% and the efficacy of fipronil ranged from 98 to 100% and 97 to 100% against C. f. felis and C. f. strongylus. There were no significant differences between the control of C. f. felis and C. f. strongylus by the three products.