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。     

12种植物精油对两种仓储害虫熏蒸活性的研究

采用水蒸气蒸馏法提取12种香料植物精油,密闭容器熏蒸法测定精油对赤拟谷盗和花斑皮蠹的熏蒸活性,为仓储害虫的生物防治提供依据。结果表明:精油熏蒸处理24 h后,在3个筛选浓度(166.67、33.33、6.67μL/L)下,5种植物精油(大蒜、花椒、小茴香、肉桂和八角茴香)对赤拟谷盗表现出较好的熏蒸活性,在高浓度(166.67、33.33μL/L)时,熏蒸致死率达到90%,在低浓度6.67μL/L时,致死率依然在60%以上;5种精油对赤拟谷盗的LC_(50)分别为0.71、1.15、1.39、1.58、1.73 mg/L。4种植物精油(大蒜、肉桂、小茴香和八角茴香)对花斑皮蠹的熏蒸活性最好,在高浓度(166.67μL/L、33.33μL/L)时,致死率高达100%,在低浓度(6.67μL/L)时,致死率均在80%以上;4种精油的LC_(50)分别为0.41、1.03、2.92、3.28 mg/L。12种植物精油中,大蒜精油对两种仓储害虫的熏蒸活性最好,且大蒜精油资源丰富,原料易得,对人类安全无毒,可成为理想的绿色环保仓储害虫熏蒸剂。     

辣椒素对储粮害虫防治效果研究

以2%辣椒素乙醇溶液均匀喷雾添加于糙米,研究辣椒素对储粮害虫玉米象和赤拟谷盗的拒食和增殖作用。结果表明:辣椒素添加量为4,2g/kg.糙米时,玉米象和赤拟谷盗表现出明显的拒食现象,30d内糙米的因虫损失率,玉米象两个浓度处理组仅为空白对照的26.4%和35.4%;赤拟谷盗处理组仅为空白对照的24.8%和30.6%;辣椒素的添加剂量为0.5g/kg.糙米时,玉米象组、赤拟谷盗组增殖数量分别为空白组的9.23%,26.1%;辣椒素的添加剂量为2g/kg.糙米时,玉米象组存活数仅1头,赤拟谷盗存活数为0。辣椒素的添加使玉米象和赤拟谷盗的增殖受到了明显抑制。     

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.     

土荆芥挥发油对玉米象和赤拟谷盗的熏蒸、触杀与驱避活性

研究土荆芥挥发油的化学成分及对玉米象和赤拟谷盗的熏蒸、触杀与驱避活性。用水蒸气蒸馏的方法提取土荆芥挥发油,气相-质谱法分析挥发油的化学成分;用密闭熏蒸法、点滴法与滤纸扩散法对玉米象和赤拟谷盗的熏蒸、触杀与驱避活性进行了测定。从土荆芥挥发油中共检出96种化合物,相对含量较高的有：（+）-4-蒈烯（36.136%）、2-蒈烯（23.897%）、邻伞花烃（10.992%）、驱蛔素环氧化物（9.047%）,驱蛔素（4.882%）等。土荆芥挥发油对玉米象和赤拟谷盗熏蒸活性LC50 值分别为1.35 mg/L和2.83 mg/L;对玉米象和赤拟谷盗的触杀活性LD50值分别为16.80 μg/头和29.35 μg/头;当浓度为58.975 ??g/cm2时,处理2 h和4 h,土荆芥挥发油对玉米象的驱避率分别为45%和47%,对赤拟谷盗的驱避率分别为76 %和80 %。土荆芥挥发油对玉米象和赤拟谷盗两种仓储害虫均有良好的熏蒸、触杀与驱避活性,可望从土荆芥挥发油中发现对两种仓储害虫具有良好生物活性的化合物。     

辽宁地区储粮害虫对磷化氢抗性测定及对策研究

运用联合国粮农组织(FAO)1975年推荐的测定储粮害虫磷化氢抗性的方法,对采自辽宁大连地区的玉米象和赤拟谷盗等2个品种7个品系的储粮害虫进行了抗性测定.试验结果表明,大连地区玉米象和赤拟谷盗均为低抗品系.通过对试验结果进行分析,提出延缓害虫对磷化氢抗性发展的相应对策,为今后科学防治储粮害虫提供了一定的参考依据.     

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%.     

多杀菌素纳米水剂防治两种储粮害虫的应用研究

采用拌粮法对已感染锯谷盗和锈赤扁谷盗的稻谷原粮进行处理,以明确多杀菌素新剂型对两种储粮害虫的杀虫效果。实验结果表明,锯谷盗对多杀菌素纳米水剂的敏感性低于锈赤扁谷盗,供试药剂对锯谷盗和锈赤扁谷盗的最高校正死亡率分别为71.70%和90.29%。测定了不同浓度的多杀菌素纳米水剂与甲基嘧啶磷乳油复配防治效果,结果表明,锯谷盗和锈赤扁谷盗的校正死亡率分别在82.90%和97.95%以上,均显著高于单剂使用多杀菌素纳米水剂的防治效果。研究发现多杀菌素纳米水剂的防治效果受昆虫种类、药剂浓度、处理时间和环境温度等因素的影响。在实际应用中,可结合多种影响因素,改进应用技术,综合制定防治策略,有效防治储粮害虫。     

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。     

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。     

石菖蒲根茎甲醇提取物对玉米象和赤拟谷盗的生物活性

采用甲醇冷浸法和溶剂萃取法,研究了石菖蒲根茎提取物对玉米象和赤拟谷盗的触杀、熏蒸、忌避、种群抑制活性和防治效果。结果表明:石菖蒲甲醇提取物以石油醚萃取物的生物活性最强;石油醚萃取物对玉米象具有较好的触杀、忌避、种群抑制活性和防治效果,药膜法处理72h后对玉米象的LC50和LC95分别为38.54μg/cm2和160.70μg/cm2,滤纸药膜法39.30μg/cm2处理24h后的忌避率为83.83%,饲料拌药法1 000mg/kg处理后对玉米象的种群抑制率、防效与10mg/kg马拉硫磷处理效果差异均不显著;石油醚萃取物对赤拟谷盗具有很高的忌避活性,滤纸药膜法39.30μg/cm2处理72h后对其忌避率为91.17%。     

Toxicity of Schizonpeta multifida essential oil and its constituent compounds towards two grain storage insects

BACKGROUND: The essential oil derived from the flowering aerial parts of Schizonpeta multifida was investigated for insecticidal activity against two grain storage insects, maize weevil (Sitophilus zeamais) and red flour beetle (Tribolium castaneum). RESULTS: The main constituents of the essential oil were menthone (40.34%) and pulegone (26.87%), followed by D ‐limonene (5.81%) and isomenthone (5.14%). Bioactivity‐directed chromatographic separation on repeated silica gel columns led to the isolation of menthone and pulegone. Pulegone showed pronounced contact toxicity against S. zeamais and T. castaneum adults (7 day LD₅₀ = 14.46 and 1.55 µg per adult respectively) and was more toxic than menthone (7 day LD₅₀ = 33.47 and 2.67 µg per adult respectively), while the crude essential oil had 7 day LD₅₀ values of 30.17 and 2.75 µg per adult respectively. Pulegone also displayed strong fumigant toxicity against S. zeamais and T. castaneum adults (7 day LC₅₀ = 3.47 and 11.56 mg cm^?3 respectively) and was again more toxic than menthone (7 day LC₅₀ = 10.32 and 31.25 mg cm^?3 respectively), while the crude essential oil had 7 day LC₅₀ values of 8.33 and 26.41 mg cm^?3 respectively. CONCLUSION: The essential oil of S. multifida and its two main components may have potential to be developed as new natural fumigants/insecticides for the control of stored product insects. Copyright © 2011 Society of Chemical Industry     

Progress towards a multi-species lure: comparison of behavioural bioassay methods for multi-species attractants against three pests of stored grain

The object of the study reported here was to establish the best behavioural bioassay to ascertain the responses of three representative species of stored-grain insect pests to potentially attractive odours. The insects tested were Oryzaephilus surinamensis, Sitophilus granarius and Cryptolestes ferrugineus. Following consideration of different types of behavioural bioassay, the Y-tube olfactometer and the pitfall bioassay were chosen for comparison. Both were tested with a representative substance known to be attractive to the test species: carob (Ceratonia siliqua) aeration extract in pentane, and a pentane control. A number of physical and biological factors were taken into account in order to ascertain the most efficient bioassay method while retaining similarity to the natural environment of the insects. The Y-tube olfactometer was used with these species for the first time and it gave good differentiation between test and control with O. surinamensis and S. granarius but not with C. ferrugineus. With the pitfall bioassay, the optimum conditions for screening potential attractants for all three species were 20°C and 50% relative humidity, with a bioassay duration of 1 h. Therefore, the optimum bioassay method for mixed sex adults of the three species tested was the pitfall bioassay. The increased response to the attractant with increased temperature (from 15°C to 20°C) shows that changing temperature may affect the insects’ responses.     

Insecticidal and residual effect of three pyrethroids against Sitophilus oryzae (L.) (Coleoptera: Curculionidae) on stored wheat

Laboratory tests were conducted to assess the use of the pyrethroids, deltamethrin, beta-cyfluthrin and alpha-cypermethrin at the rates of 0.125 and 0.25 ppm, as grain protectants in stored wheat against the rice weevil, Sitophilus oryzae (L.). For this purpose, clean untreated wheat was sprayed with these insecticides and stored for 6 months. During this period, four bioassays were carried out, in order to evaluate the residual efficacy of each pyrethroid. In each bioassay, treated wheat was infested with S. oryzae adults, and dead insects were counted after 1, 2 and 7 d of exposure. In addition, S. oryzae progeny production was estimated on each bioassay, until the production of the F₄ generation. The results indicated that deltamethrin and beta-cyfluthrin, both at 0.25 ppm, were significantly more efficient than the other treatments. Efficacy was notably higher after 7 d of exposure, than after 1 and 2 d. At the same exposure level, 1, 2 and 3.5 months after treatment, at 0.25 ppm, mortality for deltamethrin was approximately 89%, 92% and 86%, respectively, while the corresponding percentages for beta-cyfluthrin were 97%, 83% and 62%, and for alpha-cypermethrin 50%, 49% and 33%. However, at the rate of 0.125 ppm, mortality was ?58% in all cases. In all treatments appearance of F₁-F₄ generations was observed, with the exception of both deltamethrin and beta-cyfluthrin at 0.25 ppm, where only a few F₁ adults were noted, without the production of subsequent generations.