甲酸乙酯熏蒸菜豆象的初步研究

本文利用广口瓶密闭熏蒸法,测定了不同浓度、时间和温度条件下甲酸乙酯对菜豆象的熏蒸效果。结果表明:选用浓度为45μL/L处理24 h或50μL/L处理12 h,均能使其成虫达到90%以上的死亡率,说明甲酸乙酯具有良好的速效性;菜豆象的熏蒸效果随熏蒸浓度的增加、温度的升高和时间的延长而逐渐增强;各虫态耐药性比较表明:甲酸乙酯浓度的高低对菜豆象各虫态耐药性影响较大,低浓度下卵的耐药性最差,而高浓度下成虫和卵的耐药性最差。     

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。     

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     

4种植物精油对米象的熏蒸活性研究

研究了辣根素、香茅醛、1,8-桉叶油素、a-蒎烯等4种植物精油对米象的熏蒸活性。结果表明,这4种精油对米象均具有较好的熏蒸效果,辣根素、香茅醛、1,8-桉叶油素和a-蒎烯对米象的LC50分别为:0.658μL/L、4.466μL/L、4.824μL/L、5.178μL/L。米象对4种精油的敏感性依次为辣根素>香茅醛>1.8-桉叶油素>a-蒎烯。     

甲酸乙酯的施药高度对仓内空间杀虫效果的影响

在储粮容量7000t的高大平房仓空仓内,设置一个高7.50 m、直径300mm的熏蒸室,分别在7.50m、5.61m、3.74m、1.87m和0.1m的高度放置试虫,先后从0.10m、3.74m和7.50m的高度施药,测定了甲酸乙酯对处于不同高度的赤拟谷盗(Tribolium castaneum(Herbst))和谷蠹(Rhyzopertha dominica(Fabricius))成虫的杀虫效果。结果为:在0.10m高度施药,甲酸乙酯对于靠近施药点的试虫可完全致死,而在1.87m及其以上高度处的害虫死亡率均显著低于施药点的死亡率。在高度3.74m处施药,施药点及其以下两种害虫的死亡率均显著大于施药点以上的害虫死亡率,3.74m及其以下的谷蠹均完全死亡,赤拟谷盗的死亡率则出现了0.1m处100%,1.87m和3.74m处则分别只有96.7%和81%。经7.50m高度施药,0.10m高度处的害虫死亡率达100%,且害虫死亡率出现自下而上递减的结果。本实验表明,作为熏蒸剂的甲酸乙酯在空间被施用后,静态条件下向上扩散且有效杀虫的高度小于2m;在高空施药后主要扩散趋势为向下运动(下沉),对施药点以下的害虫效果较好,建...     

辣根素对绿豆象不同虫态的熏蒸活性研究

利用三角瓶熏蒸法,测定了辣根素在28℃下对绿豆象不同虫态的熏蒸效果。结果表明:在28℃下,熏蒸处理24h后,辣根素对绿豆象卵、幼虫、蛹、成虫的LC50值依次为:0.071μL/L,0.618μL/L,0.576μL/L,0.115μL/L。辣根素对绿豆象的亚致死效应明显。经过辣根素熏蒸后的绿豆象幼虫、蛹,其发育总历期无论雌虫、雄虫均显著延长。在幼虫阶段经过熏蒸后,辣根素对整个种群性比影响显著;在超过0.49μL/L剂量后,其种群性比明显低于对照以及其他各个剂量处理。     

甲酸乙酯对不同磷化氢抗性水平赤拟谷盗的毒力比较

参考FAO推荐的熏蒸剂毒力测定方法,测定了甲酸乙酯对4种不同磷化氢抗性水平的赤拟谷盗(Tribolium castaneum(Herbst))品系的毒力.主要结果为甲酸乙酯对4个磷化氢抗性系数分别为1、3、170和247倍的赤拟谷盗品系的LD50值相应地为17.354L/m3、18.776L/m3、20.464L/m3和21.470 mL/m3.结果表明,不同磷化氢抗性的赤拟谷盗品系对甲酸乙酯的敏感相似,对磷化氢具有明显抗性的赤拟谷盗对甲酸乙酯未表现出抗性.     

雅脊金小蜂长翅型雌蜂对米象种群的控制作用

雅脊金小蜂Theocolax elegans（West．）是我国南方重要仓储害虫米象Sitophilus oryzae（L．）的优势天敌。为了更好地保护和利用该蜂，采用单因子方差分析和ISD多重比较，在实验室内研究了雅脊金小蜂和米象的种群数量动态，以及该蜂长翅型雌蜂对米象种群的控制作用。结果显示，在温度25℃、相对湿度65％的条件下，雅脊金小蜂和米象的世代发育历期分别约为25天和40天。按照每盒1、2、4、8、16、32、64和128头接入的寄生蜂均可定殖，并对米象种群起着控制作用。其中，接蜂64头时，即寄生蜂与米象数量比为1：6时，控制效果最好，在放蜂后第10-50天内，控制效果迭89．11％-96．47％，与其它几组试验差异显著。试验结果表明，雅脊金小蜂可以有效地控制米象的发生与危害。     

氯甲酸乙酯尾气综合利用的研究

氯甲酸乙酯生产过程中,光气过量约5％～20％,使用氯甲酸乙酯和乙醇混合物吸收尾气,通过调节反应温度、氯甲酸乙酯与乙醇配比、反应时间,吸收尾气制得的氯甲酸乙酯含量在98％以上.     

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.     

Efficacy of vaporised ethyl formate/carbon dioxide formulation against stored‐grain insects: effect of fumigant concentration,exposure time and two grain temperatures

BACKGROUND: The ethyl formate/carbon dioxide (CO₂) formulation Vapormate? is a rapid‐acting fumigant being developed for the control of stored‐grain insects. The effects have been investigated of concentration, exposure times of 1, 3, 24 and 72 h and two grain temperatures, 15 and 25 °C, on its efficacy against mixed‐stage cultures of Sitophilus oryzae (L.) Tribolium castaneum (Herbst) and strongly phosphine‐resistant Rhyzopertha dominica (F.) strain QRD569. RESULTS: High mortalities (≥92%) of mixed‐stage cultures of all three species were obtained when grain was fumigated with the formulation (193 g m^?3 ethyl formate) for 1 h. Complete control of R. dominica QRD569 and T. castaneum was achieved with 63 and 76 g m^?3 ethyl formate respectively, with exposure for 24 h, whereas mean mortality of S. oryzae was 86% under the same conditions. Mortalities of S. oryzae juvenile stages were significantly lower than adults under the conditions tested, which was due to pronounced tolerance of mid‐stage pupae to the fumigant. Reducing grain temperature from 25 to 15 °C had no effect on insect mortality. CONCLUSION: Ethyl formate/CO₂ formulation is highly effective against stored‐grain insects over a range of concentrations and exposure times. Efficacious fumigations were conducted in as little as 1 h, and a strongly phosphine‐resistant R. dominica strain was readily controlled with the fumigant. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd     

竹提取物对玉米象Sitophilus zeamais Motsch.生物活性的初步研究

研究了10种竹子提取物对玉米象种群形成的抑制作用和驱避作用。结果表明,灰水竹和短穗竹提取物对玉米象成虫的驱避效果较好,72 h驱避等级达到Ⅳ级,平均驱避率分别为77.44%和64.84%。应用索氏抽提法所得到的灰水竹提取物对玉米象成虫的驱避作用明显强于间歇振荡法所得到的提取物,驱避中浓度分别为0.9994 g/L。10 g/L的竹提取物对玉米象种群形成的抑制作用不明显,只有白纹短穗竹提取物对玉米象种群的抑制率达到50%以上。     

九种植物精油对玉米象成虫的熏蒸作用比较

采用广口瓶密闭方法,测定红桔油Citrus tangerina、柠檬叶油Citrus limonum、 红河橙油Citrus hongheensis、 山苍子油Litsea cubeba、留兰香油Mentha spicata、松节油Pinus tabulaeformis、黄樟油Cinnamonum camphora、互叶白千层油Melaleuca alternifolia、蓝桉叶油Eucalyptus globulus等9种植物精油,在熏杀浓度为16 μL/L、熏蒸时间为24、36、48及60 h条件下,对玉米象Sitophilus zeamais成虫的熏蒸活性。结果表明:黄樟油、互叶白千层油、柠檬叶油、留兰香油及松节油的熏杀效果较好,尤以黄樟油的效果最佳。黄樟油在12、24、36、48和60 h不同熏蒸时间下的LC50值分别为31.43、11.26、6.16、2.72和1.11 μL/L。可考虑将黄樟油作为磷化氢及溴甲烷的替代药物用于控制玉米象的危害。     

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     

Fumigant toxicity of volatile natural products from Korean spices and medicinal plants towards the rice weevil,Sitophilus oryzae (L)

The fumigant toxicity of various volatile constituents of essential oils extracted from sixteen Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae), was determined. The most potent toxicity was found in the essential oil from Mentha arvensis L var piperascens (LC₅₀ = 45.5 µl litre^?1 air). GC–MS analysis of essential oil from M arvensis showed it to be rich in menthol (63.2%), menthone (13.1%) and limonene (1.5%), followed in abundance by β‐pinene (0.7%), α‐pinene (0.6%) and linalool (0.2%). Treatment of S oryzae with each of these terpenes showed menthone to be most active (LC₅₀ = 12.7 µl litre^?1 air) followed by linalool (LC₅₀ = 39.2 µl litre^?1 air) and α‐pinene (LC₅₀ = 54.9 µl litre^?1 air). Studies on inhibition of acetylcholinesterase activity of S oryzae showed menthone to have a nine‐fold lower inhibitory effect than menthol, despite menthone being 8.1‐fold more toxic than menthol to the rice weevil. Different modes of toxicity of these monoterpenes towards S oryzae are discussed. © 2001 Society of Chemical Industry