甲酸乙酯对米象不同虫态的熏蒸作用

针对储粮害虫抗药性日趋严重、粮食熏蒸剂品种越来越少的现状,采用密闭熏蒸法,系统研究甲酸乙酯（EtF）在不同条件下对米象Sitophilus oryzae（L.）卵、低龄幼虫、高龄幼虫、蛹以及成虫的致死作用.在25℃条件下以40和45μL/L的药剂浓度处理米象成虫12h,其校正死亡率分别为90.541%和99.324%;以30μL/L的浓度在19、25和31℃下处理24h,校正死亡率分别为83.108%、62%和42%,表明甲酸乙酯具有良好的速效性,且在相对低温时比在相对高温时熏蒸效果好.在20、25和30℃条件下,熏蒸处理米象成虫24h,其LC50分别为25.094、28.650和30.875μL/L;处理48 h时则分别为23.101、25.805和27.316μL/L.30g/m^3的甲酸乙酯熏蒸处理米象卵、低龄幼虫、高龄幼虫和蛹24 h,对应死亡率为96.930%、99.333%、97.768%和93.386%,表明甲酸乙酯对米象低龄幼虫的熏蒸效果最好,蛹和卵对甲酸乙酯具有较高的耐药性.     

菜豆象的截获处理

长白局于 1 999年 8月首次在进口朝鲜菜豆中截获我国一类进境植物检疫危险性害虫———菜豆象Ａｃａｎｔｈｏｓｃｅｌｉｄｅｓｏｂｔｅｃｔｕｓ(Ｓａｙ) ,并按照熏蒸灭虫方案 ,对该批 1 0 8ｔ菜豆做了熏蒸除害处理。经过对灭虫效果的监测 ,确认除害处理合格 ,准予该批菜豆入境。此次截获的菜豆象成虫是在吉林省抚松县边境贸易公司长白分公司通过长白口岸从朝鲜两江道惠山市白茂贸易会社进口的菜豆中发现的 ,其包装材料为塑料袋 ,平均从每ｋｇ菜豆中捕获菜豆象成虫 5头 ,虫口密度较大。发现疫情后 ,立即采取停止进口朝鲜菜豆、对该批朝鲜菜…     

菜豆象的生物学及防治初步研究

菜豆象Ａｃａｎｔｈｏｓｃｅｌｉｄｅｓｏｂｔｅｃｔｕｓ（Ｓａｙ）在碗町室内自然条件下每年发生７代，以老熟幼虫在豆粒内越冬。幼虫４龄，初孵幼虫的蛀入率与温、湿度有密切关系。成虫产卵对寄主豆粒有明显的选择性。寄主范围较广。室内危害深度可达１ｍ以上，为害造成的损失严重。经高温５５℃处理６０分钟、６０℃处理２０分钟、低温－１５Ｃ处理１８０分钟各虫态１００％死亡。于河沙和草木灰压盖能有效阻止成虫钻入产卵和幼虫钻入危害。草木灰拌种能有效杀死初孵幼虫。花生油、菜油和香茅油滴浸卵死亡率分别是５０．７％４４．７％和１００％；３种植物油拌种防虫的效果显著，其中以花生油的防效最佳，拌种５００天后再接虫幼虫，仍未能蛀入，且对豆类的发芽率无影响。磷化氢熏蒸，温度２６℃～２７℃、４８小时，卵、幼虫和蛹１００％死亡的浓度分别是０．７７２１ｍｇ／Ｌ、０．７６１５ｍｇ／Ｌ和１．３３４０ｍｇ／Ｌ；温度１５℃～２０℃、７２小时，卵、幼虫和蛹１００％死亡的浓度分别是０．４９８４ｍｇ／Ｌ、０．３８６０ｍｇ／Ｌ和０．７６８０ｍｇ／Ｌ。     

甲酸乙酯对三种主要仓储害虫的熏蒸作用

为明确甲酸乙酯对仓储害虫的实际控制效果,避免二氧化碳对熏蒸作用的影响,该研究利用循环熏蒸系统(FTFS),测定甲酸乙酯对米象、赤拟谷盗、谷蠹三种主要仓储害虫混合虫态的熏蒸作用.结果表明:在25℃、70%RH条件下,甲酸乙酯43.34、80.72、99.08、117.74、146.49mg/L 熏蒸处理6 h,对赤拟谷盗和谷蠹混合虫态有很好的控制作用,死亡率大于95.96%;甲酸乙酯80.72、99.08、117.74、146.49mg/L处理对米象混合虫态的杀虫效果较好.甲酸乙酯对米象蛹的杀虫效果较差.     

甲酸乙酯对面粉中赤拟谷盗的熏蒸效果

本文研究了甲酸乙酯对面粉中赤拟谷盗不同虫态的熏蒸作用。通过对熏蒸期间熏蒸剂浓度检测,计算浓度时间乘积(CT)计算不同时间下甲酸乙酯对赤拟谷盗各虫态达到99%控制的处理指标(Lct_(99))。结果表明甲酸乙酯熏蒸能有效防治面粉中的赤拟谷盗各虫态,赤拟谷盗不同虫态对甲酸乙酯的敏感性由强到弱依次为:卵>低龄幼虫>成虫>高龄幼虫>蛹。在23℃条件下处理6h和12h对面粉中赤拟谷盗的Lct_(99)分别为448.42和599.34mg·h/L     

船检中截获菜豆象

20 0 1年 1 2月 3日 ,蛇口出入境检验检疫局妈湾办事处检疫人员对一艘希腊籍船舶食品仓豆类的检疫中 ,发现一种马来西亚产的白支豆 (约 2 0ｋｇ)有豆象危害 ,经剖开豆粒 ,内有豆象成虫 ,经深圳动植食检测中心植检实验室鉴定为我国禁止进境的一类危险性害虫———菜豆象Ａｃａｎ     

磷化铝对菜豆象熏蒸杀虫效果初报

磷化铝是熏蒸灭虫处理的常用药剂。为了探索磷化铝熏蒸豆类对杀死菜豆象的有效剂量,笔者在室内条件下,用菜豆作寄主饲养截获得菜豆象供做试验材料进行熏蒸试验,现将所得结果报告如下。     

菜豆象对寄主选择性的观察

本文就菜豆象的寄主进行了试验研究。经多次试验结果,受菜豆象为害的豆类有,菜豆属、豇豆及其变种、赤豆、小豆、鹰咀豆、蚕豆、木豆等。在上述这些豆类中,菜豆象最嗜食的是菜豆属中的大菜豆、芸豆、不同品种的菜豆以及长豇豆、短豇豆、白皮豇豆等。至于对菜豆属中的利马豆,有的种能为害,有的种却不为害。菜豆象不为害的豆类是各种饭豆、豌豆、扁豆、洋刀豆以及不同品种的大豆。试验结果表明,针对菜豆象的检疫检验,按照其对寄主的选择性来区分应检的对象豆类和免检的对象豆类,这对提高检查工效与提高检出率具有实际意义。     

不同寄主对菜豆象发育和繁殖的影响

为探究不同寄主对菜豆象发育和繁殖的影响,本文选用7种豆类饲喂菜豆象,观察发育历期、存活率和繁殖力等。结果表明菜豆象在7种豆类上均能产卵,但不同豆类上卵孵化率存在差异。其中菜豆上卵孵化率最高为65.65%,红豆上最低为59.56%。幼虫仅在白芸豆、菜豆、饭豆、红豆和绿豆上蛀入危害,以菜豆上菜豆象的世代存活率最高为61.22%,绿豆上最低为46.15%。菜豆上菜豆象全世代发育历期最短为45.83 d,单雌产卵量较大为52.90粒,净增殖率值和内禀增长率值均较大分别为45.84和0.08,各生殖力生命表参数比较结果显示菜豆生殖力生命表参数优于绿豆和红豆,白芸豆和饭豆与其相类似。说明菜豆象在这3种豆类上发育较快,繁殖力较强,存活率较高。菜豆象在黄豆和黑豆上并未见其完成生活史,初步推断在这2种豆类上菜豆象无法正常发育生存。     

The relationship between the chemical composition of three essential oils and their insecticidal activity against Acanthoscelides obtectus (Say)

The chemical composition of the essential oils isolated from various parts of three Greek aromatic plants (Lavandula hybrida Rev, Rosmarinus officinalis L and Eucalyptus globulus Labill) collected at different seasons was determined by GC/MS analysis. The insecticidal action of these oils and of their main constituents on Acanthoscelides obtectus (Say) adults was evaluated and their LC50 values were estimated. All essential oils tested exhibited strong activity against A. obtectus adults, with varying LC50 values depending on insect sex and the composition of the essential oils. A correlation between total oxygenated monoterpenoid content and activity was observed, with oxygenated compounds exhibiting higher activity than hydrocarbons. Among the main constituents, only linalyl and terpinyl acetate were not active against A. obtectus, while all the others exhibited insecticidal activity against both male and female adults, with LC50 values ranging from 0.8 to 47.1 mg litre(-1) air. An attempt to correlate the insecticidal activity to the monoterpenoid's structure is presented, and the difference in sensitivity between male and female individuals is also explored.     

甲酸乙酯对米象乙酰胆碱酯酶和羧酸酯酶的影响

报道了甲酸乙酯对米象[Sitophilus oryzae(Linnaeus)]乙酰胆碱酯酶(AChE)和羧酸酯酶(CarE)的活性影响,甲酸乙酯对米象表现出很高的毒力,25℃下熏蒸处理24 h的LC₅₀为28.65μL/L。亚致死剂量的甲酸乙酯可以使米象成虫体内AChE的比活力显著下降,用20μL/L的浓度处理24 h,AChE的比活力由15.684 nmol/mg.min下降至9.530 nmol/mg.min;酶动力学研究表明,甲酸乙酯可使米象成虫体内AChE的K_m值明显增加。对于羧酸酯酶,在活体条件下表现为先抑制后激活的规律,离体条件下则主要表现为抑制作用,且随着药剂浓度的增大抑制率也增大。     

Improved efficacy of ethyl formate against stored grain insects by combination with carbon dioxide in a 'dynamic' application

Ethyl formate is being evaluated as a fumigant for stored grain as it is a potential alternative to the ozone-depleting fumigant methyl bromide and to phosphine, which is under pressure owing to the development of strong resistance in stored grain insects. However, use of ethyl formate faces significant challenges, such as poor penetration through grain, significant losses to grain sorption, high concentrations of fumigant required to control insects, and flammability risks, which have limited its further development. In this study it was found that the combination of carbon dioxide (5-20%) with ethyl formate significantly enhanced efficacy of the fumigant against external living stages of the rice weevil, Sitophilus oryzae (L.), the lesser grain borer, Rhyzopertha dominica F., and the flour beetle, Tribolium castaneum (Herbst). Dynamic application of ethyl formate and carbon dioxide mixture (100 mg litre-1 ethyl formate, 20% CO2) pumped through a model silo containing wheat (50 kg) for one gas exchange was also investigated. A flow rate of 6 litres min-1 gave a relatively even distribution of fumigant throughout the grain column and similar mortality levels among cultures of S. oryzae and T. castaneum placed at three positions, the top, middle and bottom of the column. Mortality of 99.8% of mixed stage cultures of T. castaneum and 95.1% of S. oryzae was achieved in 3 h exposures to 111 and 185 mg ethyl formate h litre-1 respectively applied by the dynamic method. It is concluded that the combination of carbon dioxide with ethyl formate and dynamic application enhances distribution and efficacy of the fumigant against stored grain insects.     

Modelling the kinetics of ethyl formate sorption by wheat using batch experiments

BACKGROUND: Ethyl formate formulations are being considered to replace methyl bromide for fast grain disinfestation. Grain adsorbs ethyl formate rapidly, which can result in inadequate fumigation concentrations and unacceptable grain residues. A model of ethyl formate sorption kinetics will enable fumigation approaches to be determined that meet disinfestation and food safety requirements. RESULTS: This paper identifies all mass transport processes involved in ethyl formate sorption by wheat from published and experimental evidence. The model accounts for reaction losses of ethyl formate in air and grain using first‐order kinetics, transport in the gas and solid phases with linear mass transfer coefficients and uses a linear partition relationship representation of sorption equilibrium. Batch experimental data were measured to determine model coefficients. Novel gaseous breakdown data for ethyl formate in air were measured, and first‐order kinetics was demonstrated, although the specific reactions involved were not identified. CONCLUSION: The model predicts air and grain fumigant concentrations relevant for grain disinfestation and food residue contamination successfully. The form of the model should be applicable to all fumigant–grain systems, as it accounts for the diffusion and reaction influences known to occur with all modern fumigants under concentration and exposure conditions relevant to industry. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd.     

Field evaluation of vaporised ethyl formate and carbon dioxide for fumigation of stored wheat

BACKGROUND: Vapormate? is a cylinderised non‐flammable mixture of ethyl formate (16.7% by weight) and carbon dioxide (CO₂) that has been developed as a rapid fumigant of stored grain. Four field trials were undertaken on wheat in 50 t farm silos to demonstrate the feasibility of dynamic application. To assess treatment efficacy, each trial tested mixed stages of Rhyzopertha dominica F. (>11 000), Tribolium castaneum (Herbst.) (>1500) and Sitophilus oryzae (L.) (>13 000) in mesh cages positioned through the centre of the grain bulk and on the grain surface. Ethyl formate and CO₂ concentrations were measured in the silo during fumigation and in ambient air outside the 6 m fumigation zone. Application rates of 420, 660 and 940 g m^?3 of ethyl formate/CO₂ formulation and exposure times of 24, 3 and 72 h, respectively, were examined using wheat of 10.4–11.7% moisture content and grain temperatures between 2 and 32 °C. RESULTS: All life stages of R. dominica and T. castaneum were fully controlled under all conditions tested, and mortality of all life stages of S. oryzae was greater than 98%. CONCLUSION: Dynamic application of vaporised ethyl formate and CO₂ to 50 t silos proved safe to operators and rapidly effective against stored‐grain insects on cold to warm grain. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd