11.1%吡虫啉缓释片剂在西瓜根区土壤的释放分布及在西瓜中的残留量分析

为了评价11.1%吡虫啉缓释片剂对西瓜蚜虫的防治效果和安全性,于2012—2013年通过田间试验于西瓜移栽时施药,研究了11.1%吡虫啉缓释片剂对西瓜蚜虫的防治效果,及其在瓜秧、果实和土壤中的残留量。结果表明:西瓜苗移栽时将11.1%吡虫啉缓释片剂(吡虫啉有效成分0.08 g/株)施入其根部下方,施药后42 d对西瓜蚜虫的防治效果为83.3%,基本可满足全生育期防治的需要。2012和2013年,11.1%吡虫啉缓释片剂在西瓜采收期(药后/移栽后60 d)的累积释放率分别为15%和32%。与吡虫啉原药处理相比,片剂中的吡虫啉在土壤中的迁移范围较小,药后30 d,施药点下方10 cm外、水平方向6 cm外的吡虫啉残留量低于0.2 mg/kg。此外,施药点下方2~4 cm处、水平方向2~4 cm处土壤中吡虫啉的残留动态基本呈单峰曲线变化,峰值均出现在药后30 d,分别为1.91和0.10 mg/kg;药后120 d分别为0.17和0.03 mg/kg。基部瓜秧中(2012年:0~30 cm;2013年:1~3节)吡虫啉的含量于药后14 d检出,其余时期均未检出;2年试验中,西瓜果实中的吡虫啉残留量均低于最低检测浓度(LOQ)0.05 mg/kg,也低于食品法典委员会(CAC)规定的西瓜中最大残留限量(MRL)0.2 mg/kg。     

树干注药对柳树叶片几种生理指标的影响

研究了4种注干液剂(吡虫啉、啶虫脒、吡虫啉·敌敌畏和敌敌畏·氧乐果)树干注射后对垂柳叶片内几种生理指标的影响。结果表明:4种药剂树干注药后均可导致垂柳叶片内可溶性总糖及纤维素含量下降,下降程度与药剂种类及注药后时间长短有关。吡虫啉对可溶性总糖含量影响最显著,药后 6 d下降了28.31%;敌敌畏·氧乐果对纤维素含量影响最显著,药后 6 d下降了19.16%。4种药剂注药后短期内均可导致叶绿素、可溶性蛋白和淀粉含量下降,但随处理时间延长其含量又明显上升。其中吡虫啉对叶绿素含量影响最显著,药后15 d升高了21.31%;敌敌畏·氧乐果对可溶性蛋白、淀粉含量影响最显著,药后15 d分别上升24.94%和 20.32%。     

吡虫啉包衣对黄瓜瓜蚜的防治效果及包衣后药剂在植株体内的分布

为探讨吡虫啉包衣对黄瓜瓜蚜的防治效果及包衣后吡虫啉在黄瓜植株体内的分布动态,以不同剂量的40%吡虫啉悬浮种衣剂包衣处理黄瓜种子,并测定了不同时间内其对瓜蚜Aphis gossypii Glover的防治效果,同时使用HPLC检测了瓜苗出土后不同时期吡虫啉在黄瓜植株各部位的分布量。结果表明,100 kg黄瓜种子用吡虫啉(有效成分)240 g、480 g和960 g的处理在瓜苗出土35 d后,瓜苗上所接瓜蚜的校正虫口减退率仍分别达到89.2%、92.0%和97.7%。经过吡虫啉包衣处理后的黄瓜种子在出苗后 3~14 d内,植株体内的吡虫啉含量逐渐增加,14 d时达到峰值后逐渐减少; 黄瓜植株不同地上部位中吡虫啉的含量不均匀,其中下部叶片药剂含量最高,其次是上部叶片,茎部最低。     

木瓜中甲拌磷农药残留分布规律

采用乙腈萃取和GC-FPD检测法,研究了甲拌磷农药在木瓜果皮、全果及果肉中的残留分布规律。结果表明,果皮中甲拌磷农药残留量最多,全果中次之,果肉中最少。喷药后10 d,果皮、全果及果肉中的残留量分别为0.084 mg/kg、0.062 mg/kg、0.045 mg/kg。随着喷药后时间的延长,果皮和全果中农药的残留量逐渐降低,果肉中甲拌磷的残留趋势为先升高后逐渐降低。     

氯氟氰虫酰胺注干剂在松树体内的残留动态

[目的]为探明氯氟氰虫酰胺注干剂在松树体内的持效时间.[方法]采用高效液相色谱法测定不同时期松树体内氯氟氰虫酰胺的含量.[结果]注干施药后5～120 d均可从样树的枝条中检测到氯氟氰虫酰胺,注药剂量为10 mL时药后15 d含量达到高峰,为16.54 mg/kg,药后120 d含量为1.24 mg/kg.[结论]松树注药5～120 d内枝条上氯氟氰虫酰胺药液浓度均高于其对松材线虫的LC50值而对松材线虫和松褐天牛等有防治抑制作用.     

吡虫啉和噻虫嗪对苜蓿盲蝽的防治效果及其在苜蓿中的残留

为了评价新烟碱类杀虫剂吡虫啉和噻虫嗪对苜蓿盲蝽的防治效果及安全性,采用田间喷雾法测定了20%吡虫啉可溶液剂(SL)和30%噻虫嗪悬浮剂(SC)对苜蓿盲蝽的防治效果,使用超高效液相色谱-串联质谱法(UPLC-MS/MS)测定了施药1、2、3次后(间隔7 d),药剂在苜蓿中的残留情况。结果表明,当吡虫啉和噻虫嗪在施药剂量分别为25.02 g/hm²和18.00 g/hm²时,药后3～7 d对苜蓿盲蝽的防治效果分别为80.01%～82.01%和77.54%～83.29%。吡虫啉和噻虫嗪连续施药3次后,在苜蓿中的最终残留量分别为1.90 mg/kg和0.08 mg/kg,吡虫啉已超过我国食品安全国家标准GB 2763-2021规定的果蔬中的最大残留限量(0.5 mg/kg)。因此建议每茬苜蓿生长期,可选用吡虫啉和噻虫嗪防治苜蓿盲蝽,吡虫啉和噻虫嗪喷施次数分别不宜超过2次和3次。     

吡虫啉在韭菜中的残留和消解动态规律研究

采用液相色谱串联质谱法测定了吡虫啉在韭菜(露天)和韭菜(保护地)中的残留消解动态和最终残留量。本方法的回收率为90.6%~103.7%,相对标准偏差为1.7%~3.3%,样品的最小检出浓度为0.01mg/kg。结果表明:吡虫啉在韭菜上残留量随时间的变化均符合一级反应动力学方程:Ct=Co×e-kt。吡虫啉在韭菜上的半衰期分别为:11.5d(露天)和10.9d(保护地)。所测得的韭菜样品中吡虫啉的最终残留量的最大值为0.34mg/kg(保护地)和0.19mg/kg(露天),均低于我国规定的吡虫啉在韭菜上的残留限量值1mg/kg。     

吡虫啉微囊种衣剂在小麦田中的剂量动态及对蚜虫防效研究

采用超高效液相色谱—串联质谱测定了吡虫啉微囊悬浮种衣剂在土壤和小麦植株组织内的剂量动态及对拔节期、灌浆期小麦蚜虫的防治效果。试验结果表明,微囊化剂型可以显著延缓吡虫啉在小麦根际土壤中的降解。种子包衣处理相同有效成分用量4 g/kg,小麦播种后175 d,微囊悬浮种衣剂处理区小麦根际土壤与小麦组织内的吡虫啉含量分别为0.80 mg/kg和0.099 mg/kg,均分别显著高于吡虫啉常规剂型处理区(0.21 mg/kg、0.035 mg/kg)。吡虫啉微囊悬浮种衣剂有效成分用量2、4 g/kg种子处理,对小麦拔节期蚜虫(药后175 d)的防效分别为92.46%、95.32%,对小麦灌浆期蚜虫(药后205 d)的防效分别为84.00%、85.07%;相同有效成分用量下,吡虫啉悬浮种衣剂处理区对小麦拔节期蚜虫的防效分别为78.01%、85.01%,对小麦灌浆期蚜虫防效分别为60.10%、65.47%;相同用量下比常规种衣剂对小麦拔节期和灌浆期蚜虫防效分别提高10%和20%。     

棉铃虫为害核桃树调查初报

2017年,在新疆维吾尔自治区阿克苏地区首次发现棉铃虫(Helicoverpa armigera)幼虫为害核桃树。棉铃虫幼虫主要为害核桃幼果,还能蛀食花序、幼嫩枝条及叶片。6月份,幼果被害率平均为5.92%。其中,果仁被害率达1.75%,其余仅为果皮与果肉部分受害;7月份,幼果被害率和果仁被害率分别为4.00%和1.00%。     

毒死蜱在梨果实不同部位的残留及消解动态

为探明毒死蜱在梨果实不同部位的残留及消解规律,以20 a生鸭梨（Pyrus bretschneideri Rehd.cv.Yali）为试材,于果实生长期在套袋后向整株喷施48%毒死蜱乳油500倍液（有效成分960 mg/L）,分析毒死蜱向果实中的运输及分配规律;于果实成熟期在采收前向果面喷施48%毒死蜱乳油1 000倍液（有效成分480 mg/L）,分析采后毒死蜱在梨果实不同组织中的分布特征。采用乙腈萃取和GC-NPD检测方法,测定不同处理试材中的毒死蜱含量。结果表明,在果实套袋情况下,整株喷施毒死蜱后72 h内果实不同部位（果心除外）毒死蜱含量均呈现先逐渐上升而后下降趋势,其中果柄、果皮和果梗洼中毒死蜱最高含量值及其出现的时间分别为6.66 mg/kg（12 h）、2.42 mg/kg（24 h）和0.09 mg/kg（12 h）,表明套袋果实毒死蜱来源于枝叶运输,经果柄进入果实后易向果皮累积;而未套袋果施药后24和72 h果皮中毒死蜱含量分别为套袋果的12.56和7.29倍,表明套袋可有效降低果实中毒死蜱的残留量。于果实成熟期向果面喷施毒死蜱后7、14和25 d,果皮中毒死蜱残留量分别为15.54、13.70和12.81 mg/kg,占全果含量的100%,而果肉中毒死蜱残留量低于本检测方法的最低检出浓度（0.05 mg/kg）,因此果皮为果实中毒死蜱主要残留部位,且贮藏期果皮中毒死蜱不易向果肉扩散。     

Spatial and temporal distribution of trunk-injected (14) C-imidacloprid in Fraxinus trees

BACKGROUND: Since the discovery of Agrilus planipennis Fairmaire (emerald ash borer) in 2002, researchers have tested several methods of chemical control. Soil drench or trunk injection products containing imidacloprid are commonly used to control adults. However, efficacy can be highly variable and may be due to uneven translocation of systemic insecticides. The purpose of this study was to determine whether sectored xylem anatomy might influence imidacloprid distribution in tree crowns. RESULTS: Imidacloprid equivalent concentrations were higher in leaves from branches in the plane of the injection point (0°) than in leaves from branches on the opposite side of the injection point (180°). Leaves from branches 90° to the right of injection points had higher imidacloprid equivalent concentrations than leaves from branches 90° to the left of injection points. Leaves and shoots had higher imidacloprid equivalent concentrations than roots and trunk cores, indicating that imidacloprid moves primarily through the xylem. CONCLUSION: Imidacloprid equivalent concentration in leaves varied over time and in relation to injection points. It is concluded that ash trees have sectored ‘zigzag’ xylem architecture patterns consistent with sectored flow distribution. This could lead to variable distribution of imidacloprid in tree crowns and therefore to variable control of A. planipennis. Copyright © 2012 Society of Chemical Industry     

喷雾和灌根施药后吡虫啉在草莓植株中的分布及其对草莓蚜虫的防效

采用喷雾和灌根两种施药方法,设置高、低两个浓度,测定吡虫啉在草莓植株中的分布及对草莓蚜虫的防效。结果表明,喷雾处理区,草莓叶片中吡虫啉初始沉积量高于茎,叶片中持留的吡虫啉消解较快,而茎中消解较慢;灌根处理区,叶片中吡虫啉积累量于药后7 d达到最大值,之后缓慢减少,茎中吡虫啉持留量在药后1~28 d相对稳定。随着时间推移,不同施药方法对蚜虫的防效不同。喷雾法短期防效(7 d内)优于灌根法,但持效期较短。灌根施药法速效性较差,但持效期长,药后7~28 d防效保持在70%以上。同时,随着施药浓度的增加,灌根法的速效性有良好的提升。     

Uptake, translocation and bioavailability of imidacloprid in several hop varieties

The neonicotinoid insecticide imidacloprid is the most important insecticide in hop cultivation in Germany. A laboratory study was undertaken to investigate its systemic properties and translaminar bioavailability in hop leaves. Radiolabelled [methylene-14C]imidacloprid was applied either alone or in combination with different additives onto leaves of several hop varieties. Uptake and translocation were evaluated 1 and 7 days after foliar application under greenhouse conditions. The uptake of imidacloprid into hop leaves was most pronounced in the first 24 h after application and only negligible amounts were taken up after this period. Significant differences in the quantitative uptake occurred when imidacloprid was combined with additives, such as Amulsol, Genapol C-100, Hasten and LI 700. The uptake of imidacloprid applied without additives was less than 10% 7 days after application, whereas the combination with LI 700 provided 70-80% uptake. Genapol C-100 and Amulsol induced considerable phytotoxicity at the application site. Comparing hop varieties revealed differences up to twofold in foliar penetration of imidacloprid. The translaminar and acropetal bioavailability of imidacloprid foliarly applied to hop leaves was determined by a laboratory bioassay using the damson hop aphid, Phorodon humuli (Schrank). Significantly higher mortality was observed with laboratory formulations containing imidacloprid and the additive LI 700. In contrast to these results from systemic tests, contact mortality at the application site was constantly high over the testing period of 7 days, highlighting the importance of this mode of entry for aphid intoxication.     

吡虫啉在生菜中的吸收迁移及转化行为

为了探究吡虫啉在植物中的吸收转运规律,本研究选择生菜为研究对象,将其在含有1 mg/kg吡虫啉的水培液中持续暴露120 h,利用超高效液相色谱-三重四极杆质谱检测吡虫啉及其5种代谢物在生菜不同部位动态吸收变化和转运分布规律.结果表明,吡虫啉在叶部富集程度明显高于根部,当达到吸收稳定状态时,吡虫啉在叶部富集程度约为根部的...     

几种药剂对吐伦球坚蚧的毒力及田间防效

为确定防治吐伦球坚蚧效果好的药剂及最佳防治时机,对吐伦球坚蚧越冬、越夏若虫进行了室内毒力测定及田间防效试验.室内毒力测定结果表明,5％啶虫脒乳油对越冬、越夏若虫活性最高,LC50分别为31.268 mg/L和22.056mg/L.田间喷雾试验,14.6％噻虫嗪+9.4％高效氯氟氰菊酯悬浮剂对越夏若虫防效达99％以上.5％啶虫脒乳油对越冬若虫防效为98.76％.注干试验,25％噻虫嗪水分散粒剂200倍液和20％吡虫啉乳油50倍液注干15 d后,对涌散期若虫防效为90.46％和94.16％;对越夏固定期若虫防效为92.51％和82.57％.以5％啶虫脒乳油和20％吡虫啉乳油对越冬若虫进行喷雾,防治效果与防治时机最佳.     

Evaluation of neonicotinoid, organophosphate and avermectin trunk injections for the management of avocado thrips in California avocado groves

BACKGROUND: Trunk injections of systemic insecticides were evaluated for the management of avocado thrips. Insecticide residues were quantified in leaves to determine when after treatment, and for how long, toxic concentrations of the insecticides were present. Residues in fruit were quantified to determine whether trunk injection of insecticides might present a greater risk than traditional application methods for contaminating fruit. RESULTS: Residues of imidacloprid and dinotefuran were at least tenfold higher in leaves when trees were treated via trunk injection compared with soil application. Dinotefuran uptake was more rapid than imidacloprid, and no residues were detected within fruit. Acephate was also mobilized very rapidly and gave good control of thrips in bioassays; however, residues of acephate and its insecticidal metabolite methamidophos were detected in the fruit for up to 4 weeks after injection. Avermectin uptake was very slow, and it was ineffective against avocado thrips. CONCLUSIONS: Trunk injections of acephate and dinotefuran permitted rapid uptake into avocados, and they are strong candidates as control methods for avocado thrips. However, residues of organophosphates in fruit could necessitate increased preharvest intervals. Residues of neonicotinoids were below detection limits in fruit, suggesting that neonicotinoids may be the more suitable control option of the two chemical classes. Copyright © 2012 Society of Chemical Industry     

灭多威和吡虫啉对棉苗缩合单宁含量的影响

为明确常用杀虫剂对棉花抗虫性的影响,研究了灭多威和吡虫啉营养液处理对棉苗中抗虫次生物质缩合单宁含量的影响。结果表明,25mg/L灭多威处理3叶期棉苗后第6、9、12和15天,50mg/L灭多威处理棉苗后第6天和第15天,棉叶中缩合单宁含量均显著增加,其中25mg/L灭多威处理棉苗15天,棉叶中缩合单宁的含量较对照增加74%。50mg/L吡虫啉处理棉苗后第2天,棉叶中缩合单宁含量与对照相比增加了45%,而吡虫啉的其它处理浓度和处理时间未对棉苗缩合单宁含量产生显著影响。杀虫剂对棉苗缩合单宁含量的影响与杀虫剂本身的性质密切相关,其中灭多威对棉苗缩合单宁含量影响较大,而吡虫啉影响则较小。此外,杀虫剂对棉苗缩合单宁含量的影响还具有一定的剂量效应与时间效应。