Effect of spray volume of two organophosphate pesticides on coverage and on mortality of California red scale Aonidiella aurantii (Maskell)

A trial under laboratory conditions was carried out to study the possibility of decreasing the delivered dose of organophosphate insecticides without affecting their efficacy against California red scale (CRS), Aonidiella aurantii (Maskell), by reducing the volume of water used whilst maintaining the concentration of pesticide. In order to establish an optimal application volume, the coverage and the efficacy against different stages of development of CRS of two commercial organophosphate pesticides (chlorpyrifos 750 g kg⁻¹ WG [Dursban^® 75 WG] and chlorpyrifos-methyl 224 g l⁻¹ EC [Reldan^® E]) at four volumes of water (1, 2, 3 and 4 ml) were compared. Results showed that in general Chlorpyrifos-methyl-based product (CMBP) provided greater coverage and impact size, but did not achieve the highest efficacy. The minimum-deposited volume (1.01 μl/cm²) produced 11% coverage with Chlorpyrifos-based product (CBP) and 22% with CMBP, reaching the highest efficacies (around 89-95%) against the youngest stages (N1 and N2 stages) with both products. To attain similar efficacy with males (prepupal and pupa stages), twice the volume (2.03 μl/cm²) of the CBP was required, producing 28% coverage. The CMBP required higher deposited volumes (3.41 μl/cm²) and higher coverage (51%). The maximum efficacy in the control of adult females (third instar and gravid female stages) was 70% with both pesticides. This level was attained with 3.41 μl/cm² of CBP (36% coverage) and 4.72 μl/cm² of CMBP (62% coverage). The research shows that greater coverage does not result in greater efficacy, so it would be possible to reduce the spray volume in field conditions. Further research will be carried out in order to check these results under real field conditions.     

重离子诱变鞘氨醇单胞菌选育毒死蜱高效降解菌株及应用

从青藏高原牦牛粪中分离出1株可降解毒死蜱的细菌,经形态和16SrDNA序列分析,鉴定其为鞘氨醇单胞菌属(Sphingomonas sp.)细菌。对其进行重离子诱变并筛选出菌株Sph-25-T1,该菌株对100mg.L-1毒死蜱的72h降解率达98.44%,比出发菌株提高27.37%。对Sph-25-T1进行传代培养,第5代时其对毒死蜱的降解率依然保持在90%以上。以喷洒毒死蜱1周后的不同土壤浸出液或蔬菜叶片做培养基时,Sph-25-T1对毒死蜱的降解率达到29.68%～78.40%。     

阿维菌素·毒死蜱对草鱼的毒性效应研究

[目的]探讨阿维菌素、毒死蜱2种药物对草鱼的毒性效应及相互关系。[方法]以健康活泼的草鱼为试验对象,用阿维菌素、毒死蜱分别对其进行单一药物的急性毒性和2种药物组合和联合毒性试验。[结果]阿维菌素、毒死蜱、2种药物混合对草鱼24、48、72、96h的LC50分别为：阿维菌素0.54、0.49、0.17、0.10 mg/L;毒死蜱0.29、0.21、0.12、0.05 mg/L;阿维菌素与毒死蜱混合药1.22、1.08、0.99、0.86 mg/L;其对草鱼的安全浓度（SC）分别为：0.010、0.005、0.086 mg/L。药物的毒性大小依次为：毒死蜱〉阿维菌素〉混合药。[结论]阿维菌素和毒死蜱混合药的不同浓度对草鱼的生长有显著影响,浓度越高毒性作用越大,低毒性强度的阿维菌素对毒死蜱具缓解作用。     

蔬菜中毒死蜱·三唑磷残留检测质量控制图的绘制及应用

为准确、可靠地检测蔬菜中毒死蜱、三唑磷残留,采用NY/T 761—2008《蔬菜和水果中有机磷、有机氯、拟除虫菊酯和氨基甲酸酯类农药多残留检测方法》,每7 d对同一质量浓度质控样品平行测定2~3次,统计20组有效数据,通过计算平均值、标准偏差得出上下控制限、警告限和辅助线,绘制出由实验室人员检测技术水平、试剂、设备、分析方法和环境因素条件下的质量控制图。该质量控制图不仅可用于实际检测过程中对检测结果进行监控,还可为实验室人员技术能力确认、实验室间比对和能力验证等分析质量控制行为提供判定依据。     

储藏和加工方式对稻谷中毒死蜱和三唑磷残留量的影响

[目的]了解稻谷加工方式和储藏方式对稻米中毒死蜱和三唑磷残留动态的影响机制。[方法]采用液相色谱-三重四极杆质谱法同时检测稻米中的毒死蜱及其代谢物3,5,6-三氯-2-吡啶酚(3,5,6-Trichloro-2-pyridinol,TCP)和三唑磷残留,分析碾磨、蒸煮、发芽加工以及储藏温度(37和4℃)对毒死蜱和三唑磷残留量的影响。[结果]毒死蜱及其代谢物TCP、三唑磷等农药残留多数分布在米糠层;短时间的蒸煮无法明显降低稻谷中毒死蜱的残留量;发芽稻谷中毒死蜱及其代谢物TCP、三唑磷的残留量显著低于未发芽稻谷;在37℃储藏条件下,毒死蜱的降解方程为C=0.899e~(-0.005t)(R~2=0.855 6),半衰期为138.6 d;三唑磷降解方程C=0.768e-0.009t(R~2=0.822 8),半衰期77.0 d,近似满足一级动力学模型方程;在4℃低温储藏条件下,稻谷中毒死蜱和三唑磷的残留量变化不大。[结论]碾磨和发芽加工有利于降低稻谷的农药残留量,低温储藏稻谷不利于残留农药的降解。研究可为稻米加工过程的风险评估以及开发稻米中农药残留的消解技术提供参考。     

毒死蜱降解菌的筛选及其特性的研究

［目的］筛选对毒死蜱具有良好降解作用的菌株,为利用微生物进行有机磷农药土壤修复提供理论依据。［方法］采用富集分离法从喷施毒死蜱的土壤中分离出4株对毒死蜱有良好降解作用的菌株,经复筛最终得到1株能够高效降解毒死蜱农药的微生物菌株D12,在充分供氧的条件下,研究菌株降解毒死蜱的降解过程、生长条件及其影响因素,并在纯培养的条件下测定该菌株对毒死蜱的降解效果。［结果］当接种量为菌浓度OD560=0.179,最适pH值为7.0,温度为30 ℃,毒死蜱浓度为100 mg/L时,该菌株D12培养6 d后的降解率达到50.4％。该菌生长的最佳毒死蜱浓度为1000 mg/L,对毒死蜱的最大耐受浓度为3 000 mg/L。［结论］试验筛选的菌株D12在基础培养基中对毒死蜱有较强的降解能力。     

不同环境温度下家蚕对毒死蜱的敏感性差异

基于高效、安全使用有机磷杀虫剂毒死蜱防治桑园害虫的目的,研究了家蚕在不同环境温度下对毒死蜱的敏感性变化。在不同温度环境中,家蚕对毒死蜱的敏感性差异变化达到极显著水平,毒死蜱对家蚕毒力的温度效应趋势模式为Y=4.083 3X4-51.582 9X3+234.664 7X2-452.663 2X+345.948。毒力的温度效应在17~21℃和29~33℃2个区域显著增强,其中低温区域温度变化对家蚕敏感性的影响大于高温区域;低温(17℃)和高温(33℃)下,家蚕对毒死蜱的敏感性增强,尤以低温(17℃)最强,校正死亡率达75.5%。     

毒死蜱不同施药方式对黄曲条跳甲的敏感性检测

本实验以黄曲条跳甲为试虫,以毒死蜱和啶虫脒为实验药剂,分别采用浸叶法和浸虫法测定了毒死蜱和啶虫脒单剂及相关混配对黄曲条跳甲的毒力。试验结果显示,毒死蜱和啶虫脒对黄曲条跳甲的浸叶LC50值分别为53．81、268．03mg／L。啶虫脒和毒死蜱按浓度比1：4混配、1：8混配浸叶LC50值分别为58．14、41．71mg／L,浸虫法结果显示啶虫脒和毒死蜱按浓度比1：4混配、1：8混配稀释4000倍液校正死亡率分别为23．3％、26．7％。     

Genistein and daidzein reduced chlorpyrifos induced damage in PC12 cell

The present study preliminarily evaluated neurotoxicity injuries induced by chlorpyrifos in PC12 ​cell, which were used as a model for nervous cell system. In cultured PC12 ​cell, application of soy isoflavones (genistein, daidzein, monomer and mixture) significantly reduced chlorpyrifos induced toxicity, a widely used pesticide, and resulted in a better cell survival rate. Treatments with isoflavones reduced malondialdehyde content, reactive oxygengeneration and acetylcholine level in medium, and maintained mitochondrial membrane potential integrity. Daidzein enhanced endogenous antioxidant system in PC12 ​cell with an increasing in superoxide dismutase per-unit activity. Genistein reduced acetylcholine content in the medium. Daidzein and genistein showed different effects, and their combined effect were greater than individual. In conclusion, soy isoflavones as an antioxidant and neuroprotectant, enhanced choline metabolism, which effectively mitigated disadvantageous influence of PC12 ​cell caused by chlorpyrifos.     

毒死蜱在枸杞果实中的残留动态研究

采用气相色谱法研究了40%毒死蜱乳油在枸杞果实内的残留动态和最终残留量.残留动态试验表明,毒死蜱在枸杞果实内消解较快,半衰期为2.87～3.15 d.在使用浓度800倍、施药2次的情况下,最后一次施药距收获间隔期7 d,枸杞果实内的残留量为0.225 mg/kg.