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。     

嗜卷书虱和嗜虫书虱酯酶性质的比较研究

对嗜卷书虱Liposcelis bostrychophila和嗜虫书虱L. entomophila羧酸酯酶及乙酰胆碱酯酶(AChE)的生物化学性质进行了初步研究。结果表明:嗜虫书虱的羧酸酯酶活性明显高于嗜卷书虱,嗜卷书虱和嗜虫书虱羧酸酯酶对底物α-NA的Km值分别为0.665 7、0.285 7 mmol/L,Vmax值分别为1.672 2和2.463 1 mmol·(mg·30 min)-1。嗜卷书虱和嗜虫书虱乙酰胆碱酯酶的活性差异不显著,嗜虫书虱略高于嗜卷书虱。通过聚丙烯酰胺凝胶电泳,检测出8条嗜卷书虱、7条嗜虫书虱酯酶同工酶谱带,嗜卷书虱的酶谱分布比嗜虫书虱广。     

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。     

磷化氢对3种储粮书虱致死浓度与时间的比较研究

比较测定了磷化氢对嗜卷书虱Liposcelis bostrychophila(Pearman)、嗜虫书虱L.entomophila(Enderlein)和小眼书虱L.paeta(Pearman)等3种储粮书虱的毒力,并研究了在室温条件下磷化氢浓度分别为100、200、300、400和500mL/m3的完全致死时间。结果表明:磷化氢对嗜卷书虱、小眼书虱和嗜虫书虱的LD50值(95%置信限)分别为0.0039(0.0038～0.0042)、0.0804(0.0750～0.0887)和0.0815(0.0815～0.0892)mg/L,嗜虫书虱对磷化氢的耐受力比嗜卷书虱高20多倍。在试验浓度下第7d可全部致死嗜卷书虱,100mL/m3的浓度完全致死小眼书虱和嗜虫书虱则需22d多;200mL/m3完全致死小眼书虱和嗜虫书虱的时间约为19d,300mL/m3浓度完全致死小眼书虱和嗜虫书虱的时间在13d和16d,400mL/m3及以上浓度完全致死小眼书虱在7d以内,完全致死嗜虫书虱仍需13d。500mL/m3的浓度完全致死嗜虫书虱仅缩短到10d。采用磷化氢熏蒸书虱在100～500mL/m3的浓度范围内,提高浓度可以使完全致死书虱的时间明显缩短。     

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。     

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。     

嗜卷书虱的实验生态研究

嗜卷书虱LiposcelisbostrychophilaBadonnel俗称书虱、啮虫,隶属于啮虫目、书虱科、书虱属。广泛存在于多种贮藏物中,大量发生时可造成严重的经济损失。但长期以来一直被认为是储粮中的次要害虫而被忽视。经调查,该虫及其近缘种嗜虫书虱LiposcelisentomophilaE.不仅在普通粮仓中发生量大,而且在目前广泛采用的气调“双低”储粮中同样发生普遍,已上升为气调储粮中的优势种群,其为害对气调储粮技术造成了极大的威胁。它们不但能传播病菌,而且大量发生时往往造成储粮水分增高,温度上升乃至发热霉变。本研究设置8种温度(17.5～35℃)及5种相对…     

不同书虱品系的磷化氢半数击倒时间与抗性相关性研究

参照FAO推荐方法测定了磷化氢对嗜卷书虱(Liposcelis bostrychophila(Badonnel))2个品系、嗜虫书虱(L.entomophila(Enderlein))3个品系和小眼书虱(L.paeta(Pearman))3个品系等共8个不同来源书虱的毒力和抗性系数Rf,测定了磷化氢浓度为2mg/mL条件下供试各书虱品系的半数击倒时间KT50,分析了其LC50值与KT50值的相关性。结果为:3种书虱的8个品系对磷化氢的抗性差异明显,高抗性的嗜虫书虱的磷化氢抗性比敏感的嗜卷书虱高1000倍以上,各品系书虱的KT50值与Rf值呈正相关,相应LC50值之对数与KT50值的对数呈直线相关。结果表明,磷化氢对书虱成虫的半数击倒时间KT50值可以用来判断书虱抗性大小,并可用于快速判断抗性以指导现场熏蒸。     

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。     

储藏根茎类中药材孳生书虱种类研究

本研究从安徽淮南采集储藏根茎类中药材样本共30种,采用直接镜检法和光照驱虫法分离其中孳生的书虱,光镜下鉴定书虱种类并计数。结果表明,30份样本中书虱的孳生率为93.3%(28/30),检获的书虱为嗜卷书虱(Liposcelis bostrychophila Motschulsky,1852);该书虱年平均孳生密度为57头/克,孳生指数为142。本研究表明安徽淮南部分储藏根茎类中药材有书虱孳生,在中药材储藏和加工过程中应注意书虱的防制。     

Acute lethal and behavioral sublethal responses of two stored-product psocids to surface insecticides

BACKGROUND: The psocids Liposcelis bostrychophila Badonnel and L. entomophila (Enderlein) (Liposcelididae) are emerging pests of stored products. Although their behavior, particularly their high mobility, may contribute to the reported relatively low efficacy of insecticides against them, studies to investigate this have not been conducted. The present study aimed to assess the label rate efficacy of three commercial insecticides (β‐cyfluthrin, chlorfenapyr and pyrethrins) applied on concrete surfaces against L. bostrychophila and L. entomophila, and also their sublethal effect on the mobility of these species. RESULTS: The synthetic insecticides β‐cyfluthrin and chlorfenapyr showed high short‐term efficacy (LT₉₅≤15 h) against both psocid species, unlike the natural pyrethrins (LT₉₅ ≥ 4 days). Liposcelis bostrychophila was slightly more tolerant (≥1.2×) than L. entomophila to all three insecticides. Behavioral assays with fully sprayed and half‐sprayed concrete arenas indicated that the insecticides reduced the mobility of both species. Pyrethrins seem to elicit weak repellence in L. bostrychophila. CONCLUSION: β‐Cyfluthrin and chlorfenapyr were effective against both psocid species, but not pyrethrins. The mobility of both species does not seem to play a major role in the differential selectivity observed, but the lower mobility of L. bostrychophila may be a contributing factor to its higher insecticide tolerance. Published in 2008 by John Wiley & Sons, Ltd.     

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.     

氟啶虫胺腈等11种杀虫剂对瓜蚜的毒力及协同增效作用

为探寻防治瓜蚜的高效协同增效药剂组合，采用叶片带虫浸渍法测定了氟啶虫胺腈等11种杀虫剂对瓜蚜的毒力。结果表明:处理后24 h，氟啶虫胺腈对瓜蚜的毒力最高，吡蚜酮最低，LC₅₀值分别为10.15和369.63 mg/L；48 h时依然是氟啶虫胺腈毒力最高，而高效氯氟氰菊酯最低，LC₅₀值分别为2.35和117.57 mg/L。在此基础上进行协同增效药剂筛选，结果表明:按质量比计，氟啶虫酰胺与吡蚜酮1 : 1、氟吡呋喃酮与吡蚜酮1 : 5、氟啶虫胺腈与吡蚜酮1 : 3、氟吡呋喃酮与高效氯氟氰菊酯1 : 5、氟啶虫胺腈与高效氯氟氰菊酯1 : 5几种组合的增效作用显著，共毒系数分别达1 271、820、561、1 277和478。研究结果可为田间瓜蚜的高效化学防治提供科学依据。     

Efficacy of grain protectants against four psocid species on maize,rice and wheat

BACKGROUND: Psocids are emerging pests in stored products, particularly in amylaceous commodities such as grains. Currently, their control is based on the use of fumigants and contact insecticides; however, newer data indicate that psocids are tolerant to insecticides used to control other stored‐grain species. This study evaluated the insecticides registered in the USA for use on stored maize, rice and wheat for control of the psocid species Lepinotus reticulatus, Liposcelis entomophila, L. bostrychophila and L. paeta. Mortality of exposed adult females was recorded after 7 and 14 days of exposure, while progeny production was assessed after 30 days of exposure. RESULTS: On wheat and rice, chlorpyriphos‐methyl + deltamethrin was generally more effective against exposed parental adults than spinosad or pyrethrin, while pirimiphos‐methyl was more effective on maize than spinosad or pyrethrin. In most cases, progeny production was suppressed in the treated grains. Progeny production was consistently lowest on wheat and rice treated with chlorpyriphos‐methyl + deltamethrin and maize treated with pirimiphos‐methyl. CONCLUSIONS: Chlorpyriphos‐methyl + deltamethrin and pirimiphos‐methyl were the most effective insecticides for all species and commodities. Conversely, efficacy of spinosad or pyrethrum was highly dependent on the psocid species and commodity. Published in 2009 by John Wiley & Sons, Ltd.     

The role of glutathione S-transferases in the detoxification of some organophosphorus insecticides in larvae and pupae of the yellow mealworm,Tenebrio molitor (Coleoptera: Tenebrionidae)

The correlation between the natural levels of glutathione S-transferase (GST) and the tolerance to the organophosphorus insecticides parathion-methyl and paraoxon-methyl, as well as the interaction of affinity-purified enzyme and the insecticides were investigated in order to collect further information on the role of the glutathione S-transferase system as a mechanism of defence against insecticides in insects. The studies were carried out on the larvae and pupae of the coleopteran Tenebrio molitor L, which exhibit varying natural levels of GST activity. Stage-dependent susceptibility of the insect against insecticides was observed during the first 24 h. However, 48 h after treatment, the KD₅₀ value increased significantly due to the recovery of some individuals. Simultaneous injection of insecticide with compounds which inhibit GST activity in vitro caused an alteration in susceptibility of insects 24 or 48 h post-treatment, depending on stage and insecticide used. Inhibition studies combined with competitive fluorescence spectroscopy revealed that the insecticides probably bind to the active site of the enzyme, thus inhibiting its activity towards 1-chloro-2,4-dinitrobenzene in a competitive manner. High-performance liquid chromatography and gas chromatography revealed that T molitor GST catalyses the conjugation of the insecticides studied to a reduced form of glutathione (GSH). From the above experimental results, it is considered that GST offers a protection against the organophosphorus insecticides studied by active site binding and subsequent conjugation with GSH. © 2001 Society of Chemical Industry     

双委夜蛾幼虫对不同类别杀虫剂的敏感性及中毒症状

为筛选防治农业新发害虫双委夜蛾Athetis dissimilis（Hampson）的有效药剂,采用浸叶法测定了其不同龄期幼虫对8类18种常用杀虫剂的敏感性,并观察了幼虫对不同药剂的中毒症状。结果表明:3~6龄双委夜蛾幼虫对辛硫磷、联苯菊酯、高效氯氟氰菊酯、溴氰菊酯、甲氨基阿维菌素苯甲酸盐、氯虫苯甲酰胺和溴氰虫酰胺的敏感性较高,LC50值为0.138 1~27.40 mg/L;3龄及4龄幼虫对毒死蜱、高效氯氰菊酯、氟啶脲、茚虫威和虫螨腈敏感性较高,LC50值小于22.63 mg/L,而5龄和6龄幼虫对上述药剂的敏感性均有所降低,LC50值大于38.13 mg/L;各龄期幼虫对甲基嘧啶磷、灭幼脲及新烟碱类杀虫剂的敏感性均较低,LC50值大于40.83 mg/L。双委夜蛾幼虫对不同类别杀虫剂的中毒症状存在差异,其中,经有机磷类、新烟碱类、吡咯类及齅二嗪类杀虫剂处理后,幼虫表现为体表干燥、体壁皱缩;而经拟除虫菊酯类杀虫剂处理后幼虫表现为体壁柔软、充满体液。就生物活性测定结果而言,推荐溴氰虫酰胺、氯虫苯甲酰胺、辛硫磷、联苯菊酯、高效氯氟氰菊酯、溴氰菊酯及甲氨基阿维菌素苯甲酸盐等药剂可用于双委夜蛾的应急防治。     

Purification and biochemical characterization of glutathione S-transferases from three strains of Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae): Implication of insecticide resistance

Glutathione S-transferases (GSTs) catalyzing the conjugation of reduced glutathione (GSH) to a vast range of xenobiotics including insecticides were investigated in the psocid Liposcelis bostrychophila Badonnel. GSTs from susceptible and two resistant strains (DDVP-R for dichlorvos-resistant strain and PH₃-R for phosphine-resistant strain) of L. bostrychophila were purified by glutathione-agarose affinity chromatography and characterized by their Michaelis-Menten kinetics towards artificial substrates, i.e., 1-chloro-2,4-dinitrobenzene (CDNB), in a photometric microplate assay. The specific activities of GSTs purified from two resistant strains were significantly higher than their susceptible counterpart. For the resistant strains, GSTs both showed a significantly higher affinity to the substrate GSH while a declined affinity to CDNB than those of susceptible strain. The inhibitory potential of ethacrynic acid was very effective with highest I₅₀ value (the concentration required to inhibit 50% of GSTs activity) of 1.21 μM recorded in DDVP-R. Carbosulfan also exhibited excellent inhibitory effects on purified GSTs. The N-terminus of the purified enzyme was sequenced by Edman degradation, and the alignment of first 13 amino acids of the N-terminal sequence with other insect GSTs suggested the purified protein was similar to those of Sigma class GSTs.     

Evaluation of toxicity and genotoxic effects of spinosad and deltamethrin in Drosophila melanogaster and Bactrocera oleae

BACKGROUND: The insecticides spinosad and deltamethrin are being increasingly used in pest management programmes. In order to assess further their toxic effects to target and non‐target insect species, an evaluation was made of their insecticidal profile on Bactrocera oleae (Rossi) and Drosophila melanogaster (Meig.). Moreover, possible genotoxic effects of the two pesticides were investigated using the somatic mutation and recombination test (SMART) in D. melanogaster. RESULTS: Both insecticides were highly effective against B. oleae, exhibiting similar LC₅₀ values. Moreover, they were found to be more effective against Bactrocera than against Drosophila adults. However, spinosad was significantly more toxic than deltamethrin to D. melanogaster. The results showed a lack of genotoxic activity of both insecticides under the in vivo experimental procedure employed, at least at applied doses. CONCLUSION: The present study provides information for lethal and sublethal effects of spinosad and deltamethrin against a target and a non‐target species. Both insecticides can exert high toxicity to B. oleae when adults are exposed even to very low doses for long periods of time. The results contribute to the database on the genotoxic potential of spinosad and deltamethrin, suggesting a safety profile for both insecticides. Copyright © 2011 Society of Chemical Industry     

Evaluation of semiochemical toxicity to Aedes aegypti,Ae. albopictus and Anopheles quadrimaculatus (Diptera: Culicidae)

BACKGROUND: Mosquitoes are the most important vectors of human pathogens. Wide‐scale use of pesticides has led to the development of resistance to most common insecticide groups. The need to develop novel products that have a low impact on human health and the environment is well established. The toxicity of selected semiochemicals with molecular structures indicative of insecticidal activity was determined against adult Aedes aegypti (L.) and Anopheles quadrimaculatus (Say). The two most active insecticides against Ae. aegypti were also evaluated against Ae. albopictus (Skuse). RESULTS: Fifteen semiochemicals classified as terpenoid alcohols, ketones or carboxylic esters showed toxicity to both mosquito species. Geranyl acetone (LC₅₀ = 38.51 µg cm^?2) followed by citronellol (LC₅₀ = 48.55 µg cm^?2) were the most toxic compounds to Ae. aegypti, while geraniol and lavonax, with LC₅₀ values of 31.88 and 43.40 µg cm^?2, showed the highest toxicity to An. quadrimaculatus. Both geranyl acetone and citronellol were highly toxic to Ae. albopioctus. No semiochemical showed fumigation activity against either species. All semiochemicals persisted for less than 24 h when tested on filter paper. CONCLUSION: Quantification of LC₅₀ values of several semiochemicals against Ae. Aegypti, An. quadrimaculatus and Ae. albopioctus showed that semiochemicals not only modify insect behaviors but also hold potential as potent insecticides for mosquito control programs. Copyright © 2010 Society of Chemical Industry