天然除虫菊素对三种储粮害虫的触杀毒力测定

采用滤纸药膜法对玉米象、谷蠹、赤拟谷盗三种储粮害虫进行了天然除虫菊素的室内毒力测定。经72 h的毒力测定,天然除虫菊素对玉米象、谷蠹、赤拟谷盗的LC50分别为0．159 mg/cm2,0．251 mg/cm2和0．096 mg/cm2。天然除虫菊素对这三种储粮害虫具有触杀作用,不同虫种对天然除虫菊素的敏感性不同。     

磷化氢亚致死浓度对赤拟谷盗卵和蛹的影响

研究了实验室条件下磷化氢亚致死浓度中赤拟谷盗卵和蛹的发育与死亡情况 .通过低的亚致死磷化氢浓度处理赤拟谷盗的卵和蛹 ,发现此虫的卵在低浓度磷化氢 ( 5mL/m3、1 0mL/m3)中仍可发育和孵化 ,且发育时间延长 ,但在磷化氢中不孵化的卵其死亡速度小于正常条件下的卵 .在稍高浓度 ( 2 0mL/m3、40mL/m3以上 )时 ,卵不能孵化 ,但从外观上也不马上死亡 ,死亡速度明显慢于对照组 .在亚致死浓度下蛹对磷化氢的耐受力较卵要小 ,同样浓度时引起的蛹死亡率也较大 ,且死亡速度快     

赤拟谷盗和玉米象的相互关系研究（网络首发、推荐阅读）

在75%RH、30 ℃条件下通过相互选择性实验、单独饲养和混合饲养实验研究赤拟谷盗和玉米象在小麦中的相互关系。研究结果表明：在相同生态环境中,赤拟谷盗和玉米象间的相互选择行为不明显。在小麦中单独饲养情况下,赤拟谷盗种群中成虫数量随处理时间延长先减少后增加,且增长缓慢,在处理56 d后最大成虫数量增加为起始虫数的11.5倍;而玉米象种群中成虫数量随处理时间延长而显著增加,在处理56 d后最大种群中成虫数量增加为起始虫量的53.9倍。与单独饲养相比,在小麦中混合饲养时,赤拟谷盗和玉米象的繁殖速率和种群中成虫数量都显著增加,在处理56 d后最大种群中成虫数量分别增加为起始虫量的20.3倍和93.4倍。因此,赤拟谷盗和玉米象均为小麦储藏过程中重要害虫,玉米象的危害对赤拟谷盗种群增长有促进作用。     

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.     

利用DNA分子指纹图谱技术检测小麦粉中害虫的研究

为开发快速检测我国成品粮中害虫的技术,研究了DNA分子指纹图谱技术检测小麦粉中主要害虫的碎片和虫卵的含量。结果表明,通过对害虫的延长因子EF1基因片段引物的筛选和PCR条件的选择,确定了有效地检测出来小麦粉中的赤拟谷盗、杂拟谷盗和锯谷盗的成虫碎片、幼虫和卵通用引物和PCR扩增条件。通过改良的PCR技术可在4 h内快速检测杂拟谷盗、锯谷盗的卵、幼虫和成虫碎片。最低检出限为可检测出小麦粉中0. 05%(m/m)卵和幼虫、1%成虫的碎片,灵敏度超过了国际标准。DNA指纹图谱中电泳条带亮度(Y)与被检测的不同害虫碎片含量(X)成正相关,回归方程为Y=858. 36X+74. 540相关系数R为0.961 9。利用该技术检测随机取样的小麦粉中成虫的碎片,检测的准确率最高可达80. 56%。结果说明了利用DNA分子指纹图谱技术可快速检测出小麦粉中害虫的碎片、幼虫和卵含量,并可预测小麦粉中害虫的感染程度。本研究为开发快速小麦粉中害虫的快速检测技术具有重要的参考意义。     

Inheritance of resistance to pyrethroid insecticides in Tribolium castaneum (Herbst)

A strain of Tribolium castaneum, highly resistant to pyrethroids, was isolated (single-pair method) from a pyrethroid-resistant field strain and made isogenic with a susceptible laboratory strain. Insecticide assays were used to determine the mode of inheritance and linkage of pyrethroid resistance. Resistance to deltamethrin could not be measured directly but at a 2% mortality response was about 1600-fold. The responses of SR and RS hybrids to deltamethrin were intermediate between the resistant and susceptible parent strains; there was no significant difference between the SR and RS hybrids (P>0.05). Chi-square analysis of the observed responses of the F₁–backcross and F₂ progenies rejected the null hypothesis that a single gene was responsible for resistance. Successive backcrosses with selection indicated the involvement of more than one gene. Test crosses with visible mutant markers suggested that resistance was associated with linkage groups VIII and IX. Assays with deltamethrin applied to grain indicated that this resistance will be rapidly selected in the field resulting in control failures.     

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     

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(R₀)、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。     

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。     

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。