13种植物精油和茴香脑对赤拟谷盗成虫熏蒸活性研究

在20μL/L的剂量下,测试了13种植物精油对赤拟谷盗成虫的熏蒸作用,其中以八角茴香油效果最佳,熏蒸24 h的校正死亡率达到100%,显著高于其他精油。随着熏蒸时间的延长,八角茴香油对赤拟谷盗的LC50值逐渐降低,熏蒸12 h时LC50值为13.88μL/L,熏蒸72 h时降为5.08μL/L,仅为熏蒸12 h的0.36倍。继而采用GC-MS技术对八角茴香油的主要组分进行分离鉴定,共从八角茴香油中鉴定出21种组分,其中茴香脑的相对百分含量为79.81%,为八角茴香油的主要成分。进一步测试了茴香脑对赤拟谷盗的熏蒸毒力,熏蒸12 h时LC50值为7.76μL/L,72 h时LC50值降为3.36μL/L,不同熏蒸时段茴香脑的LC50值均低于相应时段八角茴香油的LC50值,与八角茴香油相比,茴香脑对赤拟谷盗具有更强的熏蒸作用。     

辣根素对3种仓储害虫的熏蒸作用

在28℃环境温度下,利用三角瓶熏蒸法,测定了辣根素对3种仓储害虫的熏蒸毒力。结果表明,熏蒸48 h后,辣根素Ⅰ和辣根素Ⅱ对赤拟谷盗、谷蠹和玉米象成虫均具有明显的熏蒸效果。辣根素Ⅱ对3种仓储害虫的熏蒸效果均更好。辣根素Ⅰ熏蒸处理48 h后,对赤拟谷盗、谷蠹、玉米象成虫的毒力回归方程和LC50分别为:赤拟谷盗Y=-3.94+4.77X,6.68μL/L;谷蠹Y=-4.73+11.11X,2.67μL/L;玉米象Y=-4.22+7.47X,3.68μL/L。辣根素Ⅱ熏蒸处理48 h后,对赤拟谷盗、谷蠹、玉米象成虫的毒力回归方程和LC50分别为:赤拟谷盗Y=-4.17+5.65X,5.47μL/L;谷蠹Y=-1.82+5.39X,1.95μL/L;玉米象Y=-2.90+6.04X,3.02μL/L。     

氮气气调胁迫对赤拟谷盗生长发育及种群动态的影响研究

为明确不同氮气体积分数对赤拟谷盗生长发育和种群动态的影响,本文研究了在27~29 ℃、70~80% RH,氮气体积分数分别为78%（对照组）、90%、95%、98%下赤拟谷盗的发育历期、存活率、产卵量及其他生命表参数。研究结果表明,不同氮气体积分数对赤拟谷盗生长发育和繁殖具有显著影响。在78%、90%氮气体积分数下,增加氮气体积分数对赤拟谷盗卵、幼虫、蛹的发育有明显的抑制作用。赤拟谷盗每雌产卵量随着氮气体积分数的增加而显著减少;赤拟谷盗世代平均周期（T）、种群加倍时间（Dt）随着氮气体积分数的增加而增加。种群净增值率（R0）、种群趋势指数（I）、内禀增长率（rm）、周限增长率（λ）均随着氮气体积分数的增加而降低。当氮气体积分数为95%、98%时,赤拟谷盗不能完成世代发育。在相同氮气体积分数下赤拟谷盗各虫态间的发育历期差异显著。氮气气调处理对赤拟谷盗卵的孵化率、1~5龄幼虫及蛹的存活率均有显著的抑制作用,对赤拟谷盗6龄、7龄幼虫和预蛹的存活率无显著影响。     

北艾精油对赤拟谷盗的控制作用

为明确北艾精油对赤拟谷盗的杀虫活性,采用亚临界萃取法提取了北艾精油,用背部点滴法、滤纸药膜法和滤纸熏蒸法测定了北艾精油对赤拟谷盗不同虫态的控制作用。结果表明,北艾精油处理浓度越高,触杀效果越好,且200 μL/mL以上浓度的北艾精油对成虫和幼虫均具有很强触杀效果;北艾精油浓度和虫态显著影响了熏蒸效果,在北艾精油浓度 1 600 μL/mL以上时熏蒸死亡率达到100%,同时对幼虫熏蒸效果强于成虫;处理时间对赤拟谷盗的成虫和幼虫趋避率无显著影响,但精油浓度增加显著提高了成虫和幼虫趋避率,且在精油浓度为200 μL/mL时均达到了IV级以上水平。研究结果说明,北艾精油对赤拟谷盗具有较强的触杀、熏蒸和驱避活性。该研究结果可为利用北艾精油防治仓储害虫提供参考。     

几种植物精油对赤拟谷盗成虫的熏蒸作用

在14.7μL/L的剂量下,测试了八角茴香油、高良姜油、臭椿油、留兰香油、艾蒿油、黄樟油、薄荷油、山苍子油、辣椒油、石菖蒲油、肉豆蔻油、姜黄油、广藿香油、香茅油和芥菜油等15种植物精油对赤拟谷盗Tribolium castaneum(Herbst)成虫的熏蒸活性,结果表明八角茴香油、高良姜油、臭椿油、留兰香油、艾蒿油和黄樟油等6种植物精油对赤拟谷盗成虫具有熏蒸活性,其中八角茴香油和高良姜油的效果较好.八角茴香油对赤拟谷盗成虫的熏蒸毒力测定结果表明,当熏蒸处理24、48、72 h时,其LC50值分别为14.39、7.44、7.03μL/L.高良姜油的测定结果表明,在24、48、72 h的熏蒸处理条件下,LC50值分别为25.48、17.93、15.79μL/L.     

苦皮藤素乳油对三种储粮害虫的熏蒸作用

采用密闭熏蒸法研究了苦皮藤素乳油对储粮害虫的熏蒸作用。研究结果表明,处理24h后,苦皮藤素乳油对玉米象、赤拟谷盗和锯谷盗的LD50分别为3.606 97、2.773 78和2.048 87μg/ml;玉米象、赤拟谷盗和锯谷盗的回归方程分别为Y=3.972 64 X+2.786 68、Y=4.319 64 X+3.086 09和Y=4.095 70 X+3.724 13。三种储粮害虫对苦皮藤素乳油的敏感度由强到弱依次为锯谷盗、赤拟谷盗、玉米象。     

3种植物精油对赤拟谷盗的控制作用

采用水蒸气蒸馏的方法,从天然植物丁香、小茴香和肉桂中提取精油.并研究了3种精油对赤拟谷盗的控制作用.研究结果表明:3种植物精油对赤拟谷盗均有较强的驱避、熏蒸、触杀和种群抑制作用.其中以丁香精油的驱避和种群抑制作用最好,处理72h对赤拟谷盗的驱避率达Ⅳ级,处理7d种群抑制率达71.93%;而肉桂精油对赤拟谷盗的触杀和熏蒸作用最好,处理4d死亡率分别达73.33%和95%.     

臭椿树皮提取物对玉米象和杂拟谷盗成虫的控制作用

采用索氏提取法,利用无水乙醚作为有机溶剂提取臭椿树皮提取物,并研究其在一定浓度下对重要储粮害虫玉米象和杂拟谷盗的驱避、触杀、熏蒸和种群抑制作用.结果表明,臭椿树皮提取物对玉米象成虫的驱避作用强于对杂拟谷盗成虫的驱避作用,且随着处理时间增加驱避作用均显著下降.臭椿树皮提取物对玉米象和杂拟谷盗成虫具有较强的触杀作用和熏蒸作用,在1.5μL/cm2的处理浓度下处理72 h后触杀作用校正死亡率分别达到80.6%和88.9%,熏蒸作用校正死亡率分别为83.2%和96.8%.臭椿树皮提取物对玉米象和杂拟谷盗具有较强的种群抑制作用,对二者的当代种群抑制率均达到100%,对二者的子代种群抑制率分别达到96.2%和100%.     

磷化氢对六种甲虫的抗性品系和敏感品系的发育未成熟的毒力与防治关系

<正> 试验用谷象、米象、谷蠹、锈赤扁谷盗、锯谷盗和赤拟谷盗6个品种甲虫的13个品系(有的叫小种)的各个发育期,在15℃和25℃温度下,置于密闭的熏蒸箱内熏蒸。其中已知7个品系的成虫对磷化氢抗性。结果发现除抗品系的成虫具有抗性外,其发育未成熟期即卵、幼虫、和蛹也具有抗性,在抗性品系甲虫的整个生活史中,抗性最大的是蛹。锯谷盗、赤拟谷盗、锈赤扁谷盗和谷蠹的敏感品系各发育期,在15℃和25℃温度下,密闭4天,可以控制,虽然其中后两者在15℃时的磷化氢剂量要高达2克/米~3,但相     

千里香杜鹃提取物对赤拟谷盗、烟草甲和马铃薯茎线虫的防治作用

本文以千里香杜鹃枝、叶为实验材料，石油醚、甲醇、95%乙醇为提取剂，采用热浸法得到提取物，测试提取物对赤拟谷盗和烟草甲的触杀、熏蒸和拒食活性以及其对马铃薯茎线虫的毒杀活性，以此初步筛选出对赤拟谷盗、烟草甲和马铃薯茎线虫具有较好抗虫活性的提取物。结果表明：千里香杜鹃叶95%乙醇提取物对赤拟谷盗、烟草甲和马铃薯茎线虫具有明显杀虫活性(LD50分别为15.32、16.18 μg/头；LC50=0.78 mg/mL)；对赤拟谷盗具有明显拒食活性，在质量浓度（2 mg/mL）测试条件下，拒食率为78.17%。各提取物对赤拟谷盗和烟草甲无明显熏蒸活性。综上，千里香杜鹃叶95%乙醇提取物对赤拟谷盗、烟草甲和马铃薯茎线虫具有一定防治作用。     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

Mind the (yield) gap(s)

This paper explores the origin of the notion of ??yield gap?? and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: ??mind the (yield) gap(s)??, for they are seldom what they appear.     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.     

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (M?ssbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). M?ssbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O.     

表没食子儿茶素没食子酸酯的甲基化分子修饰

研究表没食子儿茶素没食子酸酯(EGCG)的甲基化分子修饰。以碘甲烷作为甲基供体,采用化学合成方法研究EGCG 的甲基化分子修饰,并通过HPLC-MS 和NMR 等对反应产物进行结构鉴定。结果表明：采用化学合成方法能有效完成EGCG 的甲基化分子修饰,并分离鉴定出5 个EGCG 甲基化衍生物,分别为4″-Me-EGCG、4′,4″-di-Me-EGCG、5,3′,4′,5′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,5′,3″,4″,5″-octa-Me-EGCG。     

优质农业生产管理指导手册(二)

4病虫害综合防治 病虫害综合防治(IPM)是烟叶生产的一项系统体系,利用病虫害预测预报系统,提供最好的病虫害综合防治决策,重点是协调应用一切可行的办法.病虫害综合防治并不意味着完全排除使用农药,而是在使用其它办法不能使病虫害的种群数保持在可接受的范围时适当使用农药.施用农药的地方应确保安全,并遵守一切法律法规.     

优质农业生产管理指导手册(三)

7 烘烤（调制）和烤房管理 烟叶的正确烘烤和烤房管理对优化烟叶的产量、质量和产值来说是非常关键的因素。烟叶烘烤是保持烟叶产量、质量的最后一道环节。烟叶质量会因烘烤不当而降低，而正确进行烘烤能确保烟叶质量的稳定。然而，若将劣质的鲜烟叶或烟株放入烤房，则不可能提高最终的烟叶质量。     

Attractancy of diethyl ether extracts of Arachis hypogaea (Linnaeus) (Papilionaceae), Citrullus lanatus (Thunberg) (Cucurbitaceae) and Irvingia gabonensis var. excelsa (Baillon) (Irvingiaceae) to Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae)

Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group.

Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.