气相色谱-电子捕获检测器法测定柑桔和土壤中苯丁锡的残留

建立了采用气相色谱-电子捕获检测器(GC-ECD)测定柑桔和土壤中苯丁锡残留量的分析方法。样品经乙腈提取,浓盐酸衍生化,中性氧化铝柱净化。结果表明:在0.5~5.0 mg/kg添加水平范围内,苯丁锡的平均添加回收率为92% ~98%,相对标准偏差(RSD)为5.8% ~8.7%(n=5)。方法的最小检出量(MDL)为1×10-10g,苯丁锡在桔肉、桔皮、全果和土壤4种基质中的定量限(LOQ)均为0.5 mg/kg。该方法杂质干扰少,准确性及灵敏度满足农药残留检测要求,对检测硬件要求低,适用于柑桔和土壤中苯丁锡残留的分析。消解动态试验结果表明,苯丁锡在柑桔和土壤中的消解半衰期分别为9~14 d和9~11 d,属易降解农药。     

苯丁锡·唑螨酯24%悬浮剂的高效液相色谱分析

对苯丁锡·唑螨酯24%悬浮剂测定方法进行研究。采用高效液相色谱法分析苯丁锡·唑螨酯复配制剂,使用C18反相柱和紫外可变波长检测器,以甲醇-水为流动相,流动相用磷酸调制弱酸性液体,用外标法对有效成分进行分析和定量。高效液谱分析测定苯丁锡与唑螨酯的标准偏差分别为0.17和0.11,变异系数分别为0.84%和2.62%,平均回收率分别为99.7%和99.3%。方法具有简便、快捷、精密度和准确度高的特点。     

苯丁锡防治柑桔、苹果螨类应用技术

棉花烂铃是棉花生长中后期的主要病害。生产上,调查烂铃一直采用铃面4级严重度分级计算病指的方法,直观、方便。但仅用铃面病指评价药剂的优劣,常造成误判,而用硬僵瓣重率作为评价药剂防治烂铃效果的一个指标较为科学。硬僵瓣重率是棉瓣晒干后硬僵瓣重占总棉瓣重的百分比。本文用1991、1992年试验调查结果进行了比较。     

苯丁锡防治柑桔、苹果螨类应用技术

苯丁锡是一种长效有机锡杀螨剂,防治柑桔、苹果螨类持效期可达2—3个月,且对作物安全很受农户欢迎,现将我们推广的有关技术介绍如下。1 掌握用药时间 苯丁锡属长效农药,开始活性较缓慢,喷药后1—2天仍有活螨,但基本上不能活动,食量减少,逐渐死亡。因此在螨类群体密度低时(即每叶2—3只螨)就应喷药,时间掌握好,一般施药2次就能在整个季节起到防治     

20%丙硫咪唑可湿性粉剂防治辣椒疫病试验研究

本文介绍了用20%丙硫咪唑可湿性粉剂对辣椒疫病有良好的防治效果。对辣椒有明显的增产效果。增产率为8.98%-19.57%，用商品量37.5、25、18.75g/667m^2，分别稀释2000、3000、4000倍液，防效均达84.08%，降低成本，确定用20%丙硫咪唑可湿性粉剂25g/667m^2商品量，稀释3000倍液，与72.2%普力克水剂、58%甲霜.锰锌可湿性粉剂轮换使用，可延缓抗药性的产生。     

异恶草酮气相色谱分析

论述了以邻苯二甲酸二乙酯为内标物，用HP-5色谱柱，氢火焰检测器，内标法定量气相色谱测定异恶草酮的方法。方法标准偏差为0.07，变异系数0.15%，回收率在99.3%-100.7%之间。     

再生稻纹枯病药剂防治技术改进探讨

用20％井冈霉素可溶性粉剂防治再生稻纹枯病，可有效控制纹枯病水平的扩展，始病期施药，纹枯病水平扩展防效为87.6%；始盛期施药防效为71.3%；孕穗初期施药，控制纹枯病垂直扩展防效达87％以上；用改进的防治方法对头季稻纹枯病控害效果更好，防效达91．4％。显著高于传统防治方法的防效66.9%。     

昆虫病原线虫叶面用抗干燥剂的研究

从10种蒸发抑制剂、10种保湿剂和10种乳化剂中筛选昆虫病原线虫叶面用抗干燥剂配方的研究结果表明，在25℃、相对湿度（RH）50.5%小空间湿度控制器中用不同蒸发抑制剂、保湿剂和乳化剂处理线虫Steinernema carpocapsae CB-16，18h后10% CYL（是一种蒸发抑制剂，因涉及到保密，故用第一、第二和第三作者的第一个字母的组合表示）、1%羧甲基纤维素钠和0.01B03表现出较高的抗干燥能力。用这3种物质作正交试验，筛选出最佳叶面用抗干燥剂配方为：线虫悬浮液：10% CYL:1%羧甲基纤维素钠：0.02B04=110ml:10ml:1g:0.02ml。用此配方处理过的线虫，在25℃、RH0%小空间湿度控制器内5h后，线虫存活率几乎100%。用此配方作线虫叶面用抗干燥剂防治为害兰菜花的小菜蛾（Plutella xylosella L.），在29℃、RH68%，白天有强阳光照射，线虫剂量200条/ml，防效46.5%；当线虫剂量提高到5000条/ml，防效78%。     

黏虫CYP9A134基因的克隆及其解毒功能

昆虫体内的细胞色素P450酶系统在昆虫解毒过程中发挥着重要作用。本次试验通过转录组测序获得一条新的黏虫P450基因，经国际委员会命名为CYP9A134（登录号为MT990973）。该序列全长为1801 bp，开放序列长度为1596 bp，编码531个氨基酸，分子质量为61.42 kDa，等电点为4.90。在黏虫幼虫阶段用2.5%高效氯氟氰菊酯和20%氯虫苯甲酰胺诱导时该基因表达量会有不同程度上升，最高的可分别达对照组的2.6倍和6.5倍。RNA干扰后，该基因表达量最低下降了70%，以上2种杀虫剂LD₃₀杀虫效果分别提高了13%和25%；在黏虫成虫阶段用20%氯虫苯甲酰胺LD₃₀诱导时，该基因表达量最高可达7.8倍。RNA干扰后，该基因表达量最低下降了61%，LD₃₀剂量的氯虫苯甲酰胺杀虫效果提高26%。结果表明，该基因可能在杀虫剂诱导的解毒代谢过程中发挥重要作用。     

松香 ? 海藻酸钠膜剂的制备及其对褐飞虱的防控效果

为研究防控水稻褐飞虱的新型材料，以海藻酸钠和蛋白胨为水相，通过添加由菜油和松香组成的油相，优化油相和水相的比例，制备了松香 ? 海藻酸钠膜剂，并测定了其pH值、黏度、固含量、成膜时间和耐雨水冲刷等理化性质及性能指标；采用稻秆喷雾法测定了松香 ? 海藻酸钠膜剂对褐飞虱的室内阻吸活性和田间防控效果。结果表明:当海藻酸钠、蛋白胨、松香和菜油的质量分数分别为3%、8%、12.5%和10%时，松香 ? 海藻酸钠膜剂的拉丝度、黏度和延展性达到较优值，pH值在6.34~6.91之间，黏度值为108~114 Pa ? s，固含量为38.62%，具有较好的成膜性。室内阻吸活性研究发现:用稀释50倍的膜剂处理后3 d，褐飞虱体重显著降低，减重率高达92.78%，而校正死亡率仅为20%；用稀释100倍的膜剂处理后7 d，褐飞虱的校正死亡率为59.26%。田间防效试验结果表明，膜剂稀释50倍处理对褐飞虱的防控效果与20%异丙威乳油稀释1500倍处理相当，喷施7 d后防控效果分别为64.21%和64.04%。本研究结果表明，松香 ? 海藻酸钠膜剂对水稻褐飞虱具有较好的防控效果，具有潜在应用价值，为田间病虫害的防治提供了新思路。     

Fenbutatin oxide,fate in soil after extensive commercial use in Italy and Spain

The long-term fate of the acaricide, fenbutatin oxide, in soil has been investigated. Residues of the compound and its two principal metabolites have been determined in soil samples obtained from citrus orchards in Italy and Spain where the product had been applied commercially over a period of 6–10 years. The average fenbutatin oxide content in the upper 0–15 cm soil layer ranged from ? 1 mg kg^?1 to 5 mg kg^?1 in sites receiving single and double applications per year. The residues were located primarily (> 95%) in the top 0–30 cm layer and there was virtually no movement of the compound through the soil to lower depths. Below 0.5 m depths, the sites contained average concentrations of ? 0.01 mg kg^?1, the limit of determination. No significant build-up of residues was observed and the data indicate an approximate half-life in soil of just less than one year. Residues of the two metabolites, dihydroxy-bis(2-methyl-2-phenylpropyl)stan-nane and 2-methyl-2-phenylpropyl stannonic acid, were on average 11% and 16% of the fenbutatin oxide concentration, respectively. As with fenbutatin oxide, there was no significant movement through the soil to lower levels.     

外源NO对NaCl胁迫下玉米幼苗生长和渗透调节能力的影响

采用水培法,研究了50、100、200μmol·L~(-1)外源一氧化氮(NO)供体硝普钠(SNP)对盐胁迫下玉米幼苗生长和渗透调节能力的影响。结果表明,外施NO可明显缓解Na Cl胁迫对玉米幼苗生长的抑制作用,与不施SNP的处理相比,100μmol·L~(-1)SNP处理全株干重的增加幅度达到19%。外施NO降低盐胁迫下玉米幼苗叶片及根系中可溶性糖和可溶性蛋白的含量,其中叶片中可溶性糖和可溶性蛋白分别降低19.9%和7.9%,根系中可溶性糖和可溶性蛋白含量分别降低9.6%和9%。外源一氧化氮(NO)使盐胁迫下玉米幼苗根系、生长叶和成熟叶叶鞘的Na~+含量分别降低38.4%、5.1%和17.2%;同时,增加根系和成熟叶叶鞘中K~+、Ca~(2+)、Mg~(2+)含量,降低玉米幼苗各器官内的Na~+/K~+、Na~+/Ca~(2+)比值,维持盐胁迫下玉米幼苗中的离子平衡,但对成熟叶片中离子含量的影响不大。研究认为,外源NO可维持盐胁迫下玉米幼苗的碳氮代谢平衡,改善玉米幼苗离子的吸收与分配,缓解Na Cl胁迫对玉米幼苗带来的伤害,其中以100μmol·L~(-1)的SNP处理效果最明显。     

Fenpyroximate resistance in Tetranychus urticae (Acari: Tetranychidae): cross-resistance and biochemical resistance mechanisms

A field colony of the Two-spotted spider mite, Tetranychus urticae (Koch), resistant to fenpyroximate was further selected with fenpyroximate 5SC for 20 generations at a selection pressure of 30-50% mortality (designated as FR-20 strain). Resistance and cross-resistance levels of the FR-20 strain to 18 acaricides were determined using a spray method. The FR-20 strain was extremely resistant to fenpyroximate [resistance ratio (RR) 252]. The strain exhibited extremely strong positive cross-resistance to acrinathrin (RR 196), and high levels of resistance to benzoximate (RR 55) and propargite (RR 64). Moderate levels of cross-resistance (RR 11-40) to abamectin, fenbutatin oxide, fenpropathrin, pyridaben, pyridaben + bifenthrin and tebufenpyrad were observed. The FR-20 strain showed low levels of resistance (RR < 10) to azocyclotin, bromopropylate, chlorfenapyr, chlorfenapyr + bifenthrin, chlorfenapyr + pyridaben, dicofol, fenazaquin and milbemectin. Synergist experiments with different metabolic inhibitors revealed that piperonyl butoxide had the greatest effect on the efficacy of fenpyroximate, followed by iprobenfos and triphenyl phosphate. In a comparative assay with detoxifying enzymes, the FR-20 strain showed 2.5-fold higher activity in p-nitroanisole-O-demethylation, and 2.5- and 2.2-fold higher activities in alpha- and beta-naphthyl acetate hydrolysis, respectively. These results suggested that enhanced activities of both mixed-function oxidases and esterases likely contribute to the fenpyroximate resistance of the FR-20 strain of T urticae.     

甲磺隆·氯磺隆·噻吩磺隆混剂液相色谱分析

本文采用高效液相色谱法，以C18柱为固定相，甲醇＋水＋冰乙酸为流动相．用236nm紫外检测器定量测定噻吩磺隆、甲磺隆和氯磺隆混剂的含量。本方法的变异系数分别为0．80％、0．78％、1．11％；标准偏差分别为0．084、0．084、0．114；平均回收率分别为98．9％、99．2％、99．6％；线性相关系数分别为0．9996、0．9921、0．9994。     

Ph 70–23: A new acaricide and insecticide interfering with chitin deposition

PH 70–23 is a new benzoylphenylurea interfering with chitin deposition. In larvae of Spodoptera littoralis, incorporation of N-acetyl-glucosamine into chitin was equally inhibited by PH 70–23 and diflubenzuron, the first commercially available benzoylphenylurea. In contrast to diflubenzuron, which is active only against insects and eriophyid mites, PH 70–23 has the advantage of also being highly active on spider mites. The latter activity might be partly due to leaf penetration of PH 70–23. Laboratory experiments indicate PH 70–23 to have a better ovo-larvicidal activity than the commercial acaricides tested (cyhexatin, dicofol, fenbutatin oxide and tetradifon) against Tetranychus cinnabarinus, T. turkestani, T. urticae and Panonychus ulmi. A method in which eggs were deposited on residues of cyhexatin or fenbutatin oxide resulted in much lower activities than application of the spray liquid after egg deposition. Activities of PH 70–23, dicofol and tetradifon were hardly influenced by this difference in the test method. The direct contact activity of PH 70–23 on eggs of mites is influenced by the relative humidity and the age of the eggs. The total ovolarvicidal activity of PH 70–23 is only slightly positively influenced by the relative humidity, however. Ovicidal activity of PH 70–23 is also achieved by transovarial transmission. The compound does not influence the fertility of the mites. Comparison of a strain of T. urticae, resistant to dicofol, parathion and tetradifon, with a susceptible strain indicated absence of cross-resistance to PH 70–23. Compared to diflubenzuron, PH 70–23 shows an interesting shift in the spectrum of insecticidal activity.     

Laboratory studies with antifeedants against larvae of Boarmia (Ascotis) selenaria on alfalfa

The antifeedant effect of five organotin compounds (fentin acetate, fentin hydroxide, fentin chloride, cyhexatin and fenbutatin oxide) and of three other compounds known to possess antifeeding activity (guazatine triacetate, 4′-chloroacetophenone isobutyrylhydrazone and thiram) was investigated by feeding treated alfalfa to larvae of Boarmia selenaria. The three fentins and cyhexatin were highly active at 0.1 g litre^?1, the order of activity at this concentration being fentin chloride > fentin hydroxide > fentin acetate ? cyhexatin, whereas the other compounds were practically inactive at either this or a somewhat higher concentration (0.5 g litre^?1). Guazatine triacetate had a concentration-independent antifeedant effect at much higher concentrations (5–20 g litre^?1).     

H2O2、NO和Ca2+参与疫病菌激发子PB90诱导烟草气孔的关闭

 本文研究了过氧化氢(H₂O₂)、一氧化氮(NO)和Ca²⁺在棉疫病菌激发子PB90诱导烟草气孔运动中的作用。1 nmol/L激发子PB90可诱导野生型烟草Bel-W3气孔关闭,且在相同条件下该激发子诱导反义抑制抗坏血酸过氧化物酶anti-APX烟草气孔关闭的孔径比野生型的更小;进一步药理学证明,抗氧化剂DTT和NADPH氧化酶抑制剂DPI(diphenylene iodonium)、一氧化氮合酶(NOS)抑制剂L-NAME、Ca²⁺螯合剂EGTA和Ca²⁺信号途径中CaMPK Ⅱ的竞争抑制剂KN93与磷脂酶C抑制剂U73122都能抵消PB90诱导气孔关闭的效应。推测该激发子PB90通过NADPH氧化酶途径形成H₂O₂、NOS途径形成NO和Ca²⁺信号途径进而诱导气孔关闭。表明H₂O₂、NO、Ca²⁺在激发子PB90诱导气孔关闭信号传递中作为第二信使起着重要的作用。     

New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two-spotted spider mite (Tetranychus urticae) in the UK

A recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10,000 mg litre-1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross-resisted by buprofezin-resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.     

Detection of nitric oxide in plants by electron spin resonance

ABSTRACT Three methods to detect nitric oxide (NO()) are reported here. The first method was determining NO() in extracted plant tissue. NO() was trapped by spin trapping reagent containing diethyldithiocarbamate (DETC) and FeSO(4), extracted by ethyl acetate, and determined with an electron spin resonance (ESR) spectrometer. The second method was indirectly determining NO() in live wheat leaves. Seedlings were cultured in a medium containing FeSO(4), and the leaves were brushed by DETC. Then, the leaves were ground and the complex of (DETC)(2)-Fe(2+)-NO was extracted and determined with an ESR spectrometer. The third method was directly determining NO* in live wheat leaves. After treating plant materials as in the second method, part of the water in leaves was transpired, and the leaf disks were inserted directly into quartz tubes to determine NO() with an ESR spectrometer. The NO() scavenger 2-phenyl-4,4,5,5,-tetramethylimidazoline- 1-oxyl 3-oxide (PTIO) decreased NO() signal detected either by an indirect or a direct method. This result indicates that both methods could detect NO() in the live plant. Using the first methods, we detected NO() change in wheat infected by Puccinia striiformis race CY22-2 pathogen (incompatible interaction) at different inoculation times, and it was found that the NO() content dramatically increased at 24 h postinoculation, quickly decreased at 48 h, and increased again at 96 h.