大黑粉盗与赤拟谷盗和锈赤扁谷盗对磷化氢的耐受力比较研究

潜在危害的储粮害虫大黑粉盗Cynaeus angustus研究缺乏,掌握其磷化氢耐受力有助于科学治理。采用快速击倒和FAO推荐方法测定了磷化氢对大黑粉盗的KT50值和毒力方程,并与赤拟谷盗Tribolium castaneum和锈赤扁谷盗Cryptolestes ferrugineus进行了比较,测定了100、200、300、400、500 mL/m3磷化氢模拟熏蒸中3种害虫卵、幼虫、蛹和成虫不同时间的死亡率。磷化氢对大黑粉盗、赤拟谷盗和锈赤扁谷盗的KT50值分别为7、127和3 736 min,相应毒力方程斜率值b为3.67、8.28和9.94,相应LC50值为0.008、1.34和5.88 mg/L。害虫不同虫态在100~500 mL/m3浓度下的半数致死时间LT50值于大黑粉盗卵为4~2 h、幼虫4~1 h、蛹4~1 h、成虫3~1 h,于赤拟谷盗为卵12~5 d、幼虫11~5 d、蛹13~7 d、成虫10~4 d,于锈赤扁谷盗为卵28~13 d、幼虫为18～9 d,蛹26～11 d,成虫17~9 d。相应的完全致死时间（LT100）于大黑粉盗卵为21~6 h、幼虫8~3 h、蛹9~6 h、成虫5~3 h,于赤拟谷盗卵为21~18 d、幼虫21~15 d、蛹27~18 d、成虫21~12 d,于锈赤扁谷盗卵为54~30 d、幼虫42~30 d、蛹48~30 d、成虫36~25 d。所测大黑粉盗为磷化氢敏感品系,其各虫态对磷化氢的耐受力为卵>蛹>幼虫>成虫,其耐受力远小于赤拟谷盗和锈赤扁谷盗磷化氢抗性品系。     

赤拟谷盗与锯谷盗产卵及幼虫期发育竞争研究

昆虫产卵及幼虫期发育情况对昆虫种群数量变化具有十分重要的影响。分别研究了在28℃、RH75%条件下不同起始虫数的赤拟谷盗、锯谷盗成虫单独及混合饲养子代成虫种群数量变化情况。研究发现混合饲养时赤拟谷盗的子代成虫数量较单独饲养时高,锯谷盗子代成虫数量单独与混合饲养时无明显差别。单独饲养与混合饲养时2种储粮害虫子代成虫数量回归方程的拟合度均较好。     

储藏小麦粉中害虫发生与温湿度变化的关系研究

研究了不同初始虫口密度(0、2、15头/kg小麦粉)的不同储粮害虫(锈赤扁谷盗成虫、赤拟谷盗成虫、赤拟谷盗成虫与锈赤扁谷盗成虫混合)发生对储藏小麦粉温度及环境湿度变化的影响.结果表明,在全部实验观察期间,随着实验时间延长,害虫为害引起小麦粉温度升高,初始感染害虫虫口密度越高小麦粉温度也越高;不同起始虫口密度的不同虫种害...     

S-烯虫酯防治拟谷盗持效性及解毒酶功能影响研究

在当前害虫抗药性强和社会安全健康意识增强的背景下，迫切需要开发生态友好的防治手段。因此，采用小麦入仓全仓拌和S-烯虫酯进行防治。通过分别扦取处理90天和365天后的小麦样品，在实验室内模拟了赤拟谷盗和杂拟谷盗的防治效果，并测定了S-烯虫酯对拟谷盗幼虫三种解毒酶的影响。研究结果表明，施药时间和虫态是影响S-烯虫酯杀虫效果的关键因素。在施用S-烯虫酯90天后的小麦样品中，武汉、成都和齐河3个品系的赤拟谷盗卵孵化率为0%，广东和北京2个品系的杂拟谷盗卵孵化率分别为1.67%±2.04%和0%。此外，施用S-烯虫酯90天后对赤拟谷盗和杂拟谷盗的杀蛹活性较好，羽化成虫无繁殖能力；施用365天后的杀蛹活性大大降低，羽化成虫有繁殖能力，而F1代蛹无法羽化。两处理组对两种成虫直接致死作用也有一定效果，但施用365天后的致死率大大降低，赤拟谷盗F1代仅有幼虫，而杂拟谷盗F1代有部分幼虫可化蛹但不能进一步转化为成虫。说明赤拟谷盗比杂拟谷盗更为敏感。S-烯虫酯胁迫之后，两种拟谷盗科幼虫体内的3种解毒酶活性受到了影响，且随着时间延长而增强。     

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。     

不同初始虫口密度赤拟谷盗成虫为害对小麦粉挥发性物质的影响研究

本文采用顶空固相微萃取结合GC-MS研究了起始虫口密度分别为0、6、12、18 头/kg赤拟谷盗成虫为害小麦粉不同时间后挥发性物质种类、含量及成分的变化情况。研究结果表明,被赤拟谷盗成虫为害后的小麦粉挥发性物质主要为烃类、醇类、醛类和其他物质,随着为害时间的延长,小麦粉挥发性物质总含量增加,烃类、酯类和酸类物质含量随虫口密度的增加逐渐降低,醇类物质含量先增加后降低,起始虫口密度为12 头/kg赤拟谷盗成虫为害小麦粉40 d时出现了酮类物质。不同初始虫口密度赤拟谷盗成虫为害后的小麦粉主要特征挥发性物质为1,2-15,16-二环氧十六烷、(E)-3-二十碳烯、1-十二烯、环十二烯、1-十五醇、4-异丙基-1,3-环己烷二酮、羟甲基环丙烷、1-十三烯、(Z)-2-庚醛、戊醛、17-十八炔酸和甲基苯醌。本研究结果为通过检测储粮环境挥发物变化预测害虫发生提供了科学依据。     

黄花蒿挥发油对赤拟谷盗成虫和幼虫的生物活性研究

本研究分析了黄花蒿挥发油的化学成分及其对赤拟谷盗成虫和幼虫两个阶段的防治作用。采用水蒸气蒸馏法提取挥发油,GC-MS分析挥发油的化学成分和相对含量。结果表明,黄花蒿挥发油的主要成分和含量为：蒿酮13.2%,β-芹子烯12.3%,樟脑12.2%,桉叶油醇10.3%等。生物活性测试结果显示,黄花蒿挥发油对赤拟谷盗成虫和幼虫的触杀活性LD50分别为37.32 μg/头和70.34 μg/头。同时,黄花蒿挥发油对赤拟谷盗成虫和幼虫均具有明显的驱避作用。因此,本研究能够为黄花蒿挥发油防治粮食仓储害虫提供参考。     

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。     

赤拟谷盗对小麦粉品质的影响

赤拟谷盗是小麦粉加工及储存过程中的重要害虫之一。选用普通小麦粉180g,向其中投入赤拟谷盗成虫,研究小麦粉在感染头数分别为0、10、30、60、100、200,感染时间为0、15、25、35、45d时的品质变化。实验表明:随着虫口密度的增大和感染时间的延长,小麦粉的水分稍有上升,灰分变化不大;粗淀粉含量降低,粗蛋白质含量升高,湿面筋含量和面筋指数则呈现不规律的波动;清蛋白、球蛋白、谷蛋白含量下降,醇溶蛋白的含量上升;降落数值下降明显。在较低虫口密度下时,小麦粉的峰值黏度、最低黏度、黏度破损值和最终黏度有升高趋势,但随着虫口密度的增大又逐步降低。     

哈萨克斯坦小麦挂面的感虫性研究

使用两种哈萨克斯坦小麦制挂面与国产小麦制挂面这三种样品对次生性害虫中的赤拟谷盗、锯谷盗进行了诱捕以及自然感虫实验的观察,并利用GC-IMS(气相离子迁移谱)分析三种挂面中的挥发性物质。研究结果表明在自然条件下哈麦原味挂面更容易受锯谷盗的感染；同时在饥饿12 h、诱捕8 h的条件下,锯谷盗对哈麦原味挂面的选择性最为显著,为44.38%,而在饥饿16 h、诱捕10 h的条件下,赤拟谷盗则对其选择性最显著,为53.13%。分析三种挂面挥发性物质,结果发现,三种挂面挥发性物质种类和浓度具有差异,哈麦原味挂面中浓度较高的 1-辛烯-3-醇和戊醛两种化合物可能是哈麦原味挂面感染赤拟谷盗和锯谷盗的主要风味来源,哈麦玉米风味中由于有玉米特异的风味物质,降低了两种害虫对其的选择性。     

不同温度对赤拟谷盗生长发育和繁殖的影响

分别在自然变温(室温,作为对照)、25、30、35℃和相对湿度(75±5)%条件下研究了重要储粮害虫赤拟谷盗不同虫态的发育历期、存活率、雌虫产卵量及生命表参数。研究结果表明,不同温度对赤拟谷盗生长发育和繁殖具有显著影响。在25～35℃温度范围内,赤拟谷盗卵、幼虫、蛹及整个世代发育历期均随处理温度升高而缩短,每雌产卵量均随处理温度升高而显著增加。赤拟谷盗种群趋势指数均大于1,且随温度升高而增大。赤拟谷盗净增殖率(R_0)、内禀增长率(r_m)、周限增长率(λ)均随着温度升高而增大,世代平均周期(T)、种群加倍时间(D_t)均随着温度升高而减小。     

TcYellow-h基因过表达参与介导赤拟谷盗对磷化氢的抗性形成

以赤拟谷盗为研究对象,旨在明确表皮相关基因TcYellow-h在害虫磷化氢抗性形成过程中的作用。序列分析结果表明TcYellow-h编码468个氨基酸,其拥有一段保守的MRJP(major royal jelly protein)特征序列;RT-qPCR结果显示,TcYellow-h在赤拟谷盗外周组织器官(头、胸、腹的表皮、翅和足)中表达水平较高,在内部器官(脂肪体、肠道、马氏管)中的表达量相对较低;此外,在不同地理种群中,TcYellow-h的表达量随磷化氢抗性水平的增加呈上升趋势;注射dsRNA能有效抑制TcYellow-h基因的表达,沉默效率为73.0%;干扰抗性种群(GD)TcYellow-h基因的表达后再用LC₃₀的磷化氢处理试虫,赤拟谷盗的死亡率显著上升至64.4%。本研究显示赤拟谷盗表皮相关基因Yellow-h的过表达与磷化氢的抗性形成相关。     

土荆芥提取物对谷蠹和赤拟谷盗的触杀与熏蒸活性研究

采用超声波辅助冷浸提取法以4种不同极性的溶剂(100％乙醇、丙酮、乙酸乙酯和石油醚)对土荆芥活性成分进行粗提,测试粗提物对谷蠹和赤拟谷盗的触杀与熏蒸活性.结果表明:土荆芥4种溶剂提取物对谷蠹具有明显的触杀活性,在0.468 mg/cm2剂量处理3d后致试虫校正死亡率达81.67％～ 100％;丙酮和100％乙醇提取物具有显著的熏蒸活性,丙酮提取物在0.36～0.52 g/mL处理3d后均致试虫全部死亡,100％乙醇提取物在0.52 g/mL处理下致试虫校正死亡率高达94.64％.土荆芥乙醇、丙酮和石油醚提取物对赤拟谷盗具有明显的触杀活性,在1.144 mg/cm2剂量处理3d后致试虫高达91.67％～ 100％的死亡,但4种溶剂提取物的熏蒸活性不明显.     

Distribution and efficacy of pyrethrin aerosol to control Tribolium confusum (Coleoptera: Tenebrionidae) in food storage facilities

A field test was conducted whereby adult Tribolium confusum (du Val), the confused flour beetle, were exposed in Petri dishes lined with filter paper and containing 0-2000 mg of flour, to a pyrethrin-CO₂ aerosol inside an empty warehouse. Applications were made according to label directions, and beetles were exposed to the aerosol for 2 h. After exposure, knockdown was assessed, and beetles were held for 2 weeks either in the same Petri dishes in which they were exposed or transferred with the flour to new Petri dishes lined with clean filter paper. Resident insect populations inside the test warehouse and outside were assessed through the use of pheromone traps. Virtually all beetles were knocked down at the time of removal from the exposure environment. Recovery from knockdown, or survival, increased with the presence of flour, and varied depending on the position of the exposure dishes inside the warehouse. Survival was also greater for beetles transferred along with the exposed flour to new Petri dishes lined with unexposed filter paper, compared to beetles that were held with the flour and the Petri dish that was exposed to the aerosol. Inside the warehouse, Plodia interpunctella (Hübner), the Indian meal moth, and Trogoderma variabile Ballion, the warehouse beetle, were the major species collected in pheromone traps. Large numbers of T. variabile were captured outside the warehouse, but their numbers declined during the study, while captures of P. interpunctella outside remained relatively constant. The intermittent aerosol treatments did not seem to affect these resident populations.     

5种植物精油对赤拟谷盗的驱避活性研究

为筛选新型环保植物源仓储害虫驱避剂,采用水蒸气蒸馏法提取椒蒿、香青兰、窃衣、驱虫斑鸠菊和啤酒花的植物精油,滤纸药膜法测定5种精油对赤拟谷盗成虫的驱避活性。结果表明：2 h后,在浓度为16 nL/cm2时,香青兰、窃衣、驱虫斑鸠菊、椒蒿精油对赤拟谷盗的驱避活性与阳性对照避蚊胺相当,驱避活性等级均为Ⅴ级,驱虫斑鸠菊的驱避等级稍弱于避蚊胺,驱避等级为Ⅳ级;随着浓度的降低,各精油的驱避活性随之较低,但在浓度为1.6 nL/cm2、0.16 nL/cm2时,5种植物精油的驱避活性明显高于阳性对照(驱避率为0%);在浓度为0.016 nL/cm2时,除香青兰精油具有驱避活性(驱避率为37%),驱避等级为Ⅱ级外,其他几种植物精油的驱避活性都为Ⅰ级,甚至无驱避活性;在浓度为0.0016 nL/cm2时,香青兰精油依然具有Ⅱ级的驱避活性,其他植物几乎均无驱避活性,有些还呈现吸引作用;4 h后,各精油的驱避活性均有所下降,但总体趋势与2 h无明显差异。研究结果表明香青兰精油对赤拟谷盗具有较强的驱避活性,值得进一步研究,该研究结果可为仓储害虫的无公害防治提供理论基础。     

Initial and delayed mortality of late-instar larvae, pupae, and adults of Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae) exposed at variable temperatures and time intervals

Late-instar larvae, pupae, and adults of Tribolium castaneum (Herbst), the red flour beetle, or Tribolium confusum (DuVal), the confused flour beetle, were exposed for variable durations at 36-54 °C. Beetles were placed in laboratory ovens set at a baseline of 27 °C, the temperature was increased by 0.1 °C per minute until the target temperature was achieved, and beetles were then held for specified exposure durations. There was no mortality after initial exposure or after a 1-week holding period of any life stage of T. castaneum or T. confusum exposed for 32 h to 36, 39, or 42 °C. At 45 °C, there was no initial mortality of either species exposed for different time intervals except for those exposed for 28 h. However, there was a significant increase in mortality after the 1-week holding period of those beetles exposed initially for at least 16 h to 45 °C. There was a sharp increase in mortality after the initial exposures of 4 h at 48 °C; mortality of T. confusum larvae was 90.0±5.7% but was only 10.0±10.0% for larvae of T. castaneum, and no pupae of either species were dead. All life stages of both species were killed after the initial exposure of 12 h, and 1-week mortality of beetles exposed for 4 and 8 h was generally greater than initial mortality. At 51 and 54 °C, 2- and 1-h exposures, respectively, killed all life stages of each species. Mortality in conditions of gradual temperature increase was less than previous studies with sudden temperature increases.     

Laboratory evaluation of development and survival of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) under constant temperatures

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is a serious pest of stored products. The effect of temperature on the development and survival of this species was determined at five constant temperatures (20, 25, 30, 32.5 and 35 °C) in the laboratory. Results showed a temperature-dependent development of T. castaneum. Data were fitted to the nonlinear Briere model, which for the total immature period estimated the lower threshold at 20.2 °C, the upper developmental threshold at 35.3 °C, and the temperature for maximum developmental rate at 31.2 °C. The Ikemoto and Takai linear model indicated that 659.7 degree-days above a threshold of 16.9 °C were needed to complete immature development from egg to adult emergence. Survival of immature stages varied significantly across temperatures and was well described by an extreme-value function. The model indicated that the highest survival (73.0%) was estimated to occur at 27.4 °C. The curve shows a skewed bell shape, indicating that survival decreases at both ends of the temperature range. These results are useful tools for the prediction of T. castaneum phenology, as well as for its management.     

Efficacy of chlorfenapyr against Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae) adults exposed on concrete, vinyl tile, and plywood surfaces

The insecticidal pyrrole chlorfenapyr was applied to concrete, vinyl tile, and plywood surfaces, at an application rate of 1.1 g AI m⁻². Adult Tribolium castaneum (Herbst), the red flour beetle, and adult Tribolium confusum (Du Val), the confused flour beetle, were exposed for 2 and 4 h, removed, and held without food for 7 d post-exposure. All beetles survived the initial exposures, but survival of both species decreased during the 7-d holding period, with T. confusum being the more susceptible species. Survival was generally lower on concrete than on tile or plywood, and was greatly reduced on all three surfaces after 4 h of exposure compared to 2 h. Survival of T. castaneum after 2 h of exposure on concrete, tile, and plywood was 2.5±2.5%, 25.5±15.4%, and 40.0±7.1%, respectively, after 7 d. In contrast, all T. confusum exposed on concrete and tile were dead after 4 and 5 d, respectively, while survival on plywood after 7 d was 20.0±16.8%. After 4 h of exposure, all T. castaneum and T. confusum exposed on concrete and tile were dead after 2–4 d post-exposure, while survival on plywood after 7 d was 41.5±6.4% and 0 for each species, respectively. Non-linear and linear regressions were fit to the data for both species. Results show exposure to chlorfenapyr is effective against T. castaneum and T. confusum, but efficacy will vary depending on the surface substrate.