吡丙醚和烯虫酯对嗜卷书虱控制作用的研究

采用饲料混毒法系统测定了吡丙醚和烯虫酯两种昆虫生长调节剂(IGRs)对重要的储藏物害虫嗜卷书虱Liposcelis bostrychophila Badonnel若虫和成虫的致死作用,对若虫发育情况、成虫繁殖力和卵孵化率的影响。结果表明,以吡丙醚和烯虫酯10 mg/kg的混毒饲料饲喂嗜卷书虱2龄幼虫49 d后,若虫的死亡率分别为80.00%和31.11%;取食20、10和5 mg/kg吡丙醚的若虫最长存活天数分别为71.0、98.2和116.4 d,而对照仅11.3 d即全部羽化为成虫;取食20 mg/kg以下烯虫酯混毒饲料的若虫一部分仍可羽化成成虫,而且成虫仍可繁殖后代;取食吡丙醚混毒饲料的若虫,60 d后存活下来的若虫大多以超龄若虫的形式存在,而取食烯虫酯的若虫则很少出现超龄若虫。成虫取食烯虫酯(200 mg/kg)和吡丙醚(40 mg/kg)混毒饲料后7 d,死亡率分别为26.67%和23.33%,成虫产卵量分别是对照的39.77%和26.13%,产卵后15 d,卵的孵化率分别是65.71%和8.69%,而对照仅为93.18%。该项研究表明,采用40 mg/kg吡丙醚和200 mg/kg的烯虫酯对嗜卷书虱虫口数量有明显的控制作用。     

烟粉虱与温室白粉虱羧酸酯酶、谷胱甘肽转移酶和乙酰胆碱酯酶性质的比较研究

对温室白粉虱 Trialeurodes vaporariorum和烟粉虱 Bemisia tabaci羧酸酯酶(Car E)、乙酰胆碱酯酶 (ACh E)和谷胱甘肽转移酶 (GSTs)的生物化学性质进行了初步研究。比较 Car E活性 ,烟粉虱显著高于温室白粉虱 ,烟粉虱和温室白粉虱 Car E对底物乙酸 -α-萘酯的 Km 分别为 0 .073mmol/ L 和 3.458mmol/ L。烟粉虱 ACh E活性分布高峰在 2～3m OD/ (min·头 )之间 ,而温室白粉虱 ACh E活性分布高峰在 10～ 15 m OD/ (min·头 )之间 ,烟粉虱 ACh E的 Km 值是温室白粉虱 Km 值的 12 .6倍。烟粉虱的 GSTs比活力为2 .218OD/ (mg pro·min) ,显著高于温室白粉虱的 GSTs比活力 0 .663OD/ (mg pro· min) ,差异达极显著水平 ,烟粉虱 GSTs对底物的亲和力比温室白粉虱高。     

磷化氢熏蒸处理对嗜卷书虱不同虫态的致死作用

实验室条件下系统研究了磷化氢(PH3)对储物害虫嗜卷书虱Liposcelis bostrychophila卵、各龄若虫和成虫的致死作用,并选用PH3间歇熏蒸以及PH3与气调交替处理等措施对嗜卷书虱进行处理,比较了不同处理措施对嗜卷书虱种群的控制效果。结果表明,PH3熏蒸处理对嗜卷书虱各虫态有不同的致死效果。对卵而言,24、72和120 h熏蒸处理的LC50分别为0.137、0.045和0.035 mg/L;而24 h熏蒸处理对若虫的LC50在4.285~7.364 μg/L之间,对成虫的LC50为20.404 μg/L;采用25 μg/L的PH3进行24 h熏蒸处理,间隔10 d后再分别进行第2次和第3次熏蒸处理,可以完全控制嗜卷书虱的发生。采用PH3 (12 μg/L)和气调(体积比例为35% CO2,1% O2,64% N2)交替处理能够延缓嗜卷书虱种群抗性的发展,交替处理3~5次可以完全控制嗜卷书虱的发生。     

嗜卷书虱和嗜虫书虱体内磷酸酯酶的生化与毒理学特性比较研究

采用药膜法对嗜卷书虱和嗜虫书虱进行生物测定,从5种杀虫剂对两种书虱的LC50可以看出,嗜卷书虱对两种拟除虫菊酯类药剂较嗜虫书虱敏感,嗜虫书虱对丁硫克百威较为敏感,而对有机磷类药剂的作用两种书虱的敏感性相似。两种书虱体内酸性磷酸酯酶（ACP）和碱性磷酸酯酶（ALP）的活力比较结果表明：嗜卷书虱和嗜虫书虱体内ACP的比活力为分别14 μmol/mg&#8226;30 min和2.2 μmol/mg&#8226;30 min,ALP的比活力分别为0.092 μmol/mg&#8226;30 min和0.046 μmol/mg&#8226;30 min。经方差分析,两种书虱ACP和ALP的比活力之间均存在显著性差异(p<0.05)。动力学参数比较结果显示,两种书虱ACP的V _max值之间的差异达到显著水平,而ALP的K _m值之间存在显著性差异。离体试验结果表明,5种药剂对磷酸酯酶的作用各不相同,个别药剂在低浓度下表现诱导作用,说明磷酸酯酶在不同外源毒物的解毒代谢过程中所起的作用有所不同。     

温度、湿度对嗜虫书虱生长发育和繁殖的影响

嗜虫书虱以全麦粉及酵母粉作饲料时,其各期发育速率与温度呈逻辑斯蒂曲线关系,世代发育起点和有效积温分别为15.16℃,306.75日度。在20—35℃范围内,世代存活率、种群内禀增长率以及成虫产卵量较高,高低温区均呈下降趋势。理论上29.55℃时周限增长率(λ)最大,达1.0628倍/天。高湿有利于其生长发育和繁殖,湿度低于60％时,各虫态均不能发育存活。结果表明,嗜虫书虱生长发育、繁殖最适温区为28—30℃,最适相对湿度在80％左右。     

嗜卷书虱和嗜虫书虱体内磷酸酯酶的生化与毒理学特性比较

采用药膜法对嗜卷书虱和嗜虫书虱进行生物测定,从5种杀虫剂对两种书虱的LC50可以看出,嗜卷书虱对两种拟除虫菊酯类药剂较嗜虫书虱敏感,嗜虫书虱对丁硫克百威较为敏感,而对有机磷类药剂的作用两种书虱的敏感性相似.两种书虱体内酸性磷酸酯酶(ACP)和碱性磷酸酯酶(ALP)的活力比较结果表明:嗜卷书虱和嗜虫书虱体内ACP的比活力为分别14μmol/mg·30 min和2.2 μmol/mg·30 min,ALP的比活力分别为0.092μmol/mg·30 min和0.046μmol/mg·30 min.经方差分析,两种书虱ACP和ALP的比活力之间均存在显著性差异(p<0.05).动力学参数比较结果显示,两种书虱ACP的Vmax值之间的差异达到显著水平,而ALP的Km值之间存在显著性差异.离体试验结果表明,5种药剂对磷酸酯酶的作用各不相同,个别药剂在低浓度下表现诱导作用,说明磷酸酯酶在不同外源毒物的解毒代谢过程中所起的作用有所不同.     

几种杀虫剂对嗜虫书虱的触杀作用

采用滤纸药膜法比较了常用8种杀虫剂对嗜虫书虱Liposcelis entomophila的触杀作用,在药剂的推荐浓度下有机磷类杀虫剂对嗜虫书虱的急性触杀作用强于其它药剂。同时测定了杀螟硫磷、敌敌畏和溴氰菊酯(含增效醚)3种药剂对嗜虫书虱的触杀毒力,其24h内触杀作用的LC_(50)分别为9．3284、2．1440和7．5007μg/cm~2,但杀螟硫磷的LC_(95)为459．4949μg/cm~2,远高于敌敌畏的8．2453μg/cm~2和溴氰菊酯(含增效醚)的14．5274μg/cm~2。此外,48h内敌敌畏等有机磷杀虫剂对嗜虫书虱的毒杀速度较其它供试药剂快。     

羧酸酯酶和乙酰胆碱酯酶在褐飞虱对甲胺磷抗性发展中的作用

室内抗药性筛选表明,褐飞虱对甲胺磷的抗性呈"快-慢-快"的发展趋势:第1到第4代抗性上升缓慢;第5代到第15代迅速上升,其中又呈现2个发展阶段,以第9代为拐点;第15代后抗性上升变慢。羧酸酯酶在抗药性上升中可能起到十分重要的作用,与LD50变化存在很高的相关性,达到极显著水平,相关系数为0.990 6。乙酰胆碱酯酶不敏感性在抗性发展后期变化很大,第8代到第16代间,与LD50变化存在极显著相关性,相关系数为0.970 1。由此可见,羧酸酯酶可能在褐飞虱对甲胺磷抗性的持续发展中起十分重要的作用,而乙酰胆碱酯酶不敏感性在抗性发展的后期阶段可能起到很重要作用。     

嗜卷书虱抗气性和抗药性品系选育及抗性风险分析

嗜卷书虱Liposcelis bostrychophila Badonnel是一种发生在储粮环境中的重要害虫，其抗性问题十分突出。在实验室条件下，采用高CO2（35％CO2、21％O2、44％N2）、低O2＋高CO2（35％C02、1％O2、64％N2）、DDVP和PH3等4种不同的处理，对嗜卷书虱连续处理20代，每代处理2次，每次处理保持对成虫死亡率35％的选择压力，得到了4个不同的抗性品系HCO2-R、HCLO-R、DDVP-R和PH3-R，抗性指数分别为3．3、5．2、10．2和4．5。经过对抗性发展趋势的分析，嗜卷书虱对这几种环境胁迫都有一定的抗性潜力。对抗性品系的现实遗传力（h^2）进行分析，其h^2分别为0．388、0．155、0．341和0．594。抗性风险评估结果表明，分别采用高CO2低O2＋高CO2、DDVP和PH，处理，在50％的选择压力下，抗性增加10倍所需的代数分别为62．30、44．17、26．46和38．48代；而在90％的选择压力下，抗性增加lO倍所需的代数分别为28．1l、20．08、11．98和17．39代。因此对于采用气调处理，嗜卷书虱对低O2＋高CO2处理的抗性风险比用高CO2处理大，而采用药剂处理，嗜卷书虱对DDVP的抗性风险要比PH3处理大。     

8种植物精油对嗜卷书虱的杀虫活性及香青兰精油的GC-MS成分分析

为筛选新型环保植物源仓储害虫杀虫剂,采用水蒸汽蒸馏法提取8种植物精油,滤纸药膜法、密闭空气熏蒸法测定精油对嗜卷书虱成虫的触杀、熏蒸活性,筛选出高活性植物,并用气相质谱-色谱联用仪（GC-MS）对高活性植物精油进行化学成分的分析和鉴定。结果表明：香青兰、窃衣、啤酒花精油对嗜卷书虱具有较强的触杀活性,LD₅₀分别为157.43、349.34和633.07µg/cm²;香青兰、蒌蒿和窃衣精油对嗜卷书虱具有较好的熏蒸活性,LC₅₀分别为0.20、0.70和1.66 mg/L。香青兰精油经GC-MS分析,检测并鉴定到23个化学成分,相对含量占总含量的84.22%,其主要成分为乙酸香叶酯（16.26%）、丁香酚（13.90%）、香叶醛（13.20%）、草蒿脑（7.89%）、丙烯酸-2-乙基己酯（8.55%）以及橙花醛（7.60%）。研究结果表明香青兰精油对嗜卷书虱的生物活性较好,值得进一步研究。     

寄主植物对桃蚜羧酸酯酶和乙酰胆碱酯酶的诱导作用

在１９９５～１９９６年研究了寄主植物对桃蚜［Ｍｙｚｕｓｐｅｒｓｉｃａｅ（Ｓｕｌｚｅｒ）］羧酸酯酶（ＣａｒＥ）和乙酰胆碱酯酶（ＡＣｈＥ）的诱导作用。在试验的甘蓝、茄子和桃树３种寄主植物中，取食甘蓝的桃蚜种群ＣａｒＥ和ＡＣｈＥ活性最高，取食茄子和桃树的桃蚜种群ＣａｒＥ活性没有明显不同，而ＡＣｈＥ活性取食茄子的桃蚜种群明显高于取食桃树的种群。ＣａｒＥ与底物的亲和力是桃树＞茄子＞甘蓝，而ＡＣｈＥ与底物的亲和力则是甘蓝＞茄子＞桃树。ＡＣｈＥ与毒扁豆碱的双分子速率常数（Ｋｉ）值大小顺序为甘蓝＞桃树＞茄子     

不同防治田内不同发育期拟环纹豹蛛乙酰胆碱酯酶及羧酸酯酶的活性比较

利用紫外分光光度法研究了生物防治田和化学防治田内不同发育期拟环纹豹蛛Pardosa pseudoannulata乙酰胆碱酯酶(AChE)和羧酸酯酶(CarE)的活性特征。结果表明,化防田拟环纹豹蛛各发育时期AChE活性均较生防田中的低,其各发育期AChE的Km值也均明显高于生防田种群。从整个发育期来看,幼体的AChE活性最高,卵囊的最低,说明不同发育阶段AChE活性存在较大差异。而CarE的活性正相反,化防田种群卵囊、幼蛛、雌成蛛和雄成蛛的CarE活性均高于相应生防田种群,且幼蛛的CarE活性高于相应成蛛,生防田种群每一发育阶段CarE的Km值也均高于相应的化防田种群。表明化防田中的拟环纹豹蛛有可能对部分农药产生了一定程度的抗药性。     

四种杀虫剂对两种书虱谷胱甘肽-S-转移酶和超氧化物歧化酶的影响

谷胱甘肽-S-转移酶（GSTs）能够参与多种类型杀虫剂的解毒代谢，如有机磷类、氨基甲酸酯类、拟除虫菊酯类和有机氯类。其介导的抗性与一种或多种GSTs的过量表达有关。超氧化物歧化酶（SOD）的功能是清除超氧阴离子自由基而形成H2O2，H2O2能与O2^-形成毒性更强的HO^-。书虱是一类个体微小、行动活泼的重要储藏物害虫，书虱对化学药剂的抗性发展很快，目前已发展为储粮中的害虫优势种群，但有关书虱体内酶系的研究较少。     

Comparison of biochemical and toxicological characterizations of glutathione S-transferases and superoxide dismutase between Liposcelis bostrychophila Badonnel and L. entomophila (Enderlein) (Psocoptera: Liposcelididae)

The toxicological and biochemical characteristics of glutathione S-transferases (GSTs) and superoxide dismutase (SOD) in Liposcelis bostrychophila and L. entomophila were comparatively investigated. Compared to their counterparts in L. entomophila, the activities of both GSTs and SOD from L. bostrychophila were significantly higher (P < 0.05), indicating that there was a stronger ability to eliminate the toxicants in the latter. The inhibition kinetics of insecticides revealed that dichlorvos and paraoxon possessed excellent inhibitory effects on GSTs in vitro, while there were some activated effects of chlorpyrifos on GSTs, more significant in L. entomophila. As for SOD in vivo, dichlorvos and chlorpyrifos had some inhibitory effects under the condition of sublethal concentration. However, the situation of carbosulfan was a little complex. Within the first 3 h treatment period there were facilitated effects on SOD in L. bostrychophila, and some expressed inhibitory effects. While in L. entomophila carbosulfan always possessed inhibitory effects on SOD.     

Potential of piperonyl butoxide‐synergised pyrethrins against psocids (Psocoptera: Liposcelididae) for stored‐grain protection

BACKGROUND: Piperonyl butoxide (PB)‐synergised natural pyrethrins (pyrethrin:PB ratio 1:4) were evaluated both as a grain protectant and a disinfestant against four Liposcelidid psocids: Liposcelis bostrychophila Badonnel, L. entomophila (Enderlein), L. decolor (Pearman) and L. paeta Pearman. These are key storage pests in Australia that are difficult to control with the registered grain protectants and are increasingly being reported as pests of stored products in other countries. Firstly, mortality and reproduction of adults were determined in wheat freshly treated at 0.0, 0.75, 1.5, 3 and 6 mg kg^?1 of pyrethrins + PB (1:4) at 30 ± 1 °C and 70 ± 2% RH. Next, wheat treated at 0.0, 1.5, 3 and 6 mg kg^?1 of pyrethrins + PB (1:4) was stored at 30 ± 1 °C and 70 ± 2% RH and mortality and reproduction of psocids were assessed after 0, 1.5, 3 and 4.5 months of storage. Finally, the potential of synergised pyrethrins as a disinfestant was assessed by establishing time to endpoint mortality for adult psocids exposed to wheat treated at 3 and 6 mg kg^?1 of synergised pyrethrins after 0, 3, 6, 9 and 12 h of exposure. RESULTS: Synergised pyrethrins at 6 mg kg^?1 provided 3 months of protection against all four Liposcelis spp., and at this rate complete adult mortality of these psocids can be achieved within 6 h of exposure. CONCLUSION: Piperonyl butoxide‐synergised pyrethrins have excellent potential both as a grain protectant and as a disinfestant against Liposcelidid psocids. Copyright © State of Queensland, Department of Employment, Economic Development and Innovation, 2010. Published by John Wiley and Sons, Ltd.     

Influence of concentration, temperature and humidity on the toxicity of phosphine to the strongly phosphine-resistant psocid Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)

BACKGROUND: The psocid Liposcelis bostrychophila Badonnel, is a widespread, significant pest of stored commodities, has developed strong resistance to phosphine, the major grain disinfestant. The aim was to develop effective fumigation protocols to control this resistant pest. RESULTS: Time to population extinction of all life stages (TPE) in days was evaluated at a series of phosphine concentrations and temperatures at two relative humidities. Regression analysis showed that temperature, concentration and relative humidity all contributed significantly to describing TPE (P<0.001, R(2)=0.95), with temperature being the dominant variable, accounting for 74.4% of the variation. Irrespective of phosphine concentration, TPE was longer at lower temperatures and high humidity (70% RH) and shorter at higher temperatures and low humidity (55% RH). At any concentration of phosphine, a combination of higher temperature and lower humidity provides the shortest fumigation period to control resistant L. bostrychophila. For example, 19 and 11 days of fumigation are required at 15 degrees C and 70% RH at 0.1 and 1.0 mg L(-1) of phosphine respectively, whereas only 4 and 2 days are required at 35 degrees C and 55% RH for the same respective concentrations. CONCLUSIONS: The developed fumigation protocols will provide industry with flexibility in application of phosphine.     

Inhibition of egg development by phosphine in the cosmopolitan pest of stored products Liposcelis bostrychophila (Psocoptera: Liposcelididae)

Phosphine-induced delay in development of eggs was investigated as a mechanism of resistance to this fumigant in Liposcelis bostrychophila Badonnel. One-day-old eggs of a susceptible and a strongly resistant strain of L bostrychophila were exposed to a range of phosphine concentrations for 6days at 30 (+/- 1) degrees C and 70 (+/- 2)% RH. Delay in mean hatching period occurred in both susceptible and resistant eggs, although it was more pronounced in the latter. A maximum delay of 2.65 days was recorded for eggs of the susceptible strain at 0.01 mg litre(-1) (the highest concentration at which eggs survived) and 13.39 days for the resistant strain at 1 mg litre(-1) (the highest concentration tested). Delay in egg development time was positively correlated with increasing phosphine concentration. Our results reveal that the most successful strategy to control resistant L bostrychophila is to apply relatively low concentrations of phosphine for extended exposure times (eg 0.05 mg litre(-1) for 16 days) that allow all eggs to hatch to the much less tolerant nymph stage.