Induction of a malathion-resistant strain in the common predacious mite Amblyseius cydnodactylon (Acari: Phytoseiidae)

This study demonstrates a laboratory induction of a malathion - resistant strain in Amblyseius cydnodactylon Shehata & Zaher and effect of selection on reproduction. Initially 500 sensitive females obtained from a laboratory mass culture were exposed to malathion at LC70. Subsequent selections were conducted every two generations at progressive LC70 values and number of eggs/female/day was recorded at each selection. Experiments were carried out under laboratory conditions of 24-28°C and 70-80 % R. H. The LC70 in the parent generation was 5.19 ppm and increased to 20 ppm in F4 selection generation. The dosage mortality relationships continued to increase up to a maximum of 282.3 ppm in F16. The rate of developing resistance increased from 1.75 folds in F2 to 1.97 folds in F4 and gradually reached a maximum of 54.39 folds in F16. There was an obvious decrease in reproduction corresponded to increasing resistance. For example, the number of eggs/female/day in F 16 was 8 eggs, contrasting 3 eggs in the parent generation.     

Effect of a mixture of iprobenfos and malathion on the development of malathion resistance in the mosquito Culex pipiens pallens Coq

A malathion-resistant (RM) strain of Culex pipiens pallens Coq was obtained by successively selecting a field population with malathion in the laboratory. The synergistic effect of iprobenfos on malathion toxicity and alpha-naphthyl acetate (alpha-NA) esterase assay revealed that malathion resistance in the RM strain was associated with increased alpha-NA esterase activity and the synergism was mainly due to the inhibition by iprobenfos of this activity. There was no difference in alpha-NA esterase activity between the larvae and female adults in the susceptible (S) strain, but the activity in the adults was 13-fold higher than in the larvae of the RM strain. To understand the effect of the application of a mixture of iprobenfos and malathion on the evolution of malathion resistance, an artificial strain (Syn) was generated by mixing the RM and S strains with 0.1 frequency of the malathion-resistant individuals. The offspring of the Syn strain were divided into two sub-strains, Rm and Rm+ibp, which were successively treated with, respectively, malathion alone and malathion + iprobenfos (1:2) at LC70. In the mixture, the fungicide iprobenfos acted as a synergist of malathion. After treatment for 10 generations, the resistance level to malathion was 317.4-fold for the Rm sub-strain, whereas for the Rm+ibp sub-strain it was only 38.9-fold, compared with the Syn strain. Similar results were obtained by measurement of alpha-NA esterase activity from both larvae and female adults. The alpha-NA esterase activities in larvae and female adults at F10 generation were 2.6- and 10.9-fold from the Rm+ibp sub-strain and 5.7- and 98.5-fold from the Rm sub-strain, respectively, compared with the Syn strain. The above results suggested that iprobenfos, although it cannot completely stop or prevent the onset of malathion resistance, could dramatically delay its evolution.     

斜纹夜蛾对茚虫威的抗药性汰选及交互抗性测定

为评估茚虫威抗性风险,在室内进行了斜纹夜蛾对茚虫威的抗性选育和交互抗性测定。经过10代6次室内抗性选育,获得了斜纹夜蛾对茚虫威抗性种群,与选育前相比,斜纹夜蛾对茚虫威的敏感性降低了15.63倍。抗性风险评估结果表明,斜纹夜蛾具有对茚虫威产生高水平抗性的风险。交互抗性测定发现,辛硫磷、高效氯氰菊酯和氟虫腈对茚虫威抗性种群的LC50值分别是同源对照种群的1.53、2.42和1.53倍,溴虫腈和灭多威对茚虫威抗性种群的LC50值分别是同源对照种群的0.78和0.96倍,表明茚虫威抗性种群对这几种杀虫剂未产生交互抗性。     

氯虫苯甲酰胺对桃小食心虫生长发育的亚致死效应

为明确亚致死浓度的氯虫苯甲酰胺连续处理对第4代桃小食心虫生物学特性的影响,本研究用LC10、LC30和LC50的氯虫苯甲酰胺处理的苹果分别继代饲养桃小食心虫（简称LC10、LC30和LC50种群）。以第4代初孵幼虫为起点记录其各阶段发育历期、存活率和繁殖力等数据,研究氯虫苯甲酰胺对桃小食心虫的亚致死效应。结果表明,LC30和LC50种群桃小食心虫的卵期与对照（CK）种群相比明显延长; LC50种群桃小食心虫的蛀果率、脱果率、幼虫存活率、世代存活率以及单雌平均产卵量均显著低于CK种群; CK、LC10、LC30和LC50种群单雌平均产卵量分别为(183.67±10.39)、(177.66±14.81)、(147.83±14.54)粒和(126.33±11.29)粒。桃小食心虫LC30和LC50种群与CK种群相比,内禀增长率、净生殖率和周限增长率显著降低,平均世代周期和种群加倍时间延长,相对适合度降低。     

副珠蜡蚧阔柄跳小蜂MetaphyCUS parasaissetiae Zhang and Huang生物学特性的研究

副珠蜡蚧阔柄跳小蜂Metaphycus parasaissetiae Zhang and Huang是新发现的橡副珠蜡蚧成虫内寄生蜂,自然寄生率约为15.68%。实验室内对其形态、发育、繁殖、存活、行为等生物学特性进行了观察。结果表明,在26±1℃,RH70%±5%条件下,每头寄主出蜂4.5头,雌性比例80.6%;雌蜂生殖系统解剖发现,未交配雌蜂卵巢内的卵经1d可发育成熟,但同一雌蜂卵巢内卵粒之间发育程度不一致;该蜂完成一个世代需15～19d,但幼虫蜕皮现象不明显;该蜂可营孤雌产雄生殖,孤雌羽化后24h内即可产卵,平均每头寄主可出雄蜂5.3头;雌蜂交配后24h内即可产卵,产卵期1～17d;1头已交配雌蜂可寄生1～10头寄主,一生产卵3～76粒,每日平均产卵量为8.2±4.0粒;雌、雄成蜂平均寿命均不超过3d,补充蜂蜜水可延长雌、雄成蜂的寿命。     

Insecticide resistance inFrankliniella occidentalis: Corroboration of laboratory assays with field data and cross-resistance in a cypermethrin-resistant strain

Field efficacy of five insecticides to a greenhouse strain ofFrankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) of known resistance status was studied. In a greenhouse trial, the mortality of aF. occidentalis strain (Uncali) which exhibited resistance only against cypermethrin in laboratory assays, reached 56%, 68%, 82%, 94% and 99%, 24 h after application of abamectin, cypermethrin, endosulfan, malathion and methomyl, respectively. In the laboratory, for larval mortality equal to that achieved in the field, much lower doses — half of the field dose of cypermethrin and endosulfan, and one-third and one-sixth of malathion and methomyl, respectively, were required in topical application. Because of differences between laboratory and field responses ofF. occidentalis to insecticides, a sound resistance evaluation program to determine field efficacy of insecticides is needed. Resistance increased 28.0- and 139.3-fold at LC₅₀ in theF. occidentalis strain subjected to 27 and 44 cycles of cypermethrin selection, respectively. A slight cross-resistance of two- to threefold was found with endosulfan, malathion and methomyl and no cross-resistance was observed with abamectin. http://www.phytoparasitica.org posting August 4, 2008.     

吡虫啉对豌豆蚜的亚致死效应

室内测定了吡虫啉的亚致死剂量（LC20、LC30、LC40）对豌豆蚜的生长发育、繁殖和种群参数的影响。结果表明,随着吡虫啉亚致死剂量的增加,豌豆蚜F0代成蚜的寿命显著缩短,产蚜量显著降低。亚致死剂量也使F1代种群的内禀增长率、净增殖率和周限增长率降低,而发育历期、平均世代周期和种群加倍时间延长。     

东方钝绥螨生物学及食量研究

东方钝绥螨在昌黎地区每年大约发生23代左右。平均卵期1.8天,幼虫期0.7天、第一若虫期1.0天、第二若虫期1.5天、产卵前期4.6天、产卵期15.2天、雌成螨期20.5天、雄成螨期15.6天、生命周期为25.5天。平均日产卵量1.5粒,总卵量16粒。雌成螨日捕食山楂叶螨卵3粒及若螨0.46头,总捕食量为卵91粒,若螨43头及成山楂叶螨14头,对苹果全爪螨捕食量3.4头(雌成螨)。     

西花蓟马与豆大蓟马成虫数量和性别对彼此产卵量的影响

为明确西花蓟马Frankliniella occidentalis和豆大蓟马Megalurothrips usitatu共存时的生殖竞争,采用叶盘法测定了孤雌生殖方式下和两性生殖方式下,接入不同数量西花蓟马雌、雄成虫后,豆大蓟马日产卵量和总产卵量;接入不同数量豆大蓟马雌、雄成虫后,西花蓟马的日产卵量和总产卵量,明确了2种蓟马成虫数量和性别对彼此日产卵量和总产卵量的影响。在豆大蓟马孤雌生殖方式下,1头西花蓟马雌成虫即可使其日产卵量和总产卵量显著降低,由8.8粒和61.6粒分别下降至7.5粒和52.4粒,而1头西花蓟马雄成虫对其产卵量无显著影响;在豆大蓟马两性生殖方式下,1头西花蓟马雌成虫同样可显著降低其日产卵量和总产卵量,由6.6粒和46.2粒分别下降至5.2粒和36.6粒,1头西花蓟马雄成虫也可显著降低其产卵量,分别下降至5.9粒和41.4粒;西花蓟马雌成虫对2种生殖方式下豆大蓟马产卵量的影响均显著或极显著大于雄成虫。在西花蓟马孤雌生殖方式下,1头豆大蓟马雌成虫和雄成虫即可显著降低其产卵量,日产卵量由6.8粒均下降至6.1粒,总产卵量由47.4粒分别下降至43.0粒和42.6粒;在西花蓟马两性生殖方式下,1头豆大蓟马雌成虫同样可显著降低西花蓟马的日产卵量和总产卵量,分别由6.1粒和43.0粒下降至4.3粒和30.0粒,但2头豆大蓟马雄成虫才可使其产卵量显著降低;豆大蓟马雌成虫对西花蓟马2种生殖方式下产卵量的影响大于雄成虫。无论是否受到干扰,豆大蓟马2种生殖方式下的日产卵量和总产卵量均高于西花蓟马。表明在西花蓟马与豆大蓟马的生殖竞争中,由于豆大蓟马的繁殖力较高,在竞争中占据优势地位。     

两种亚致死剂量的农药对亚洲玉米螟化学通讯系统的干扰作用

采用胸部点滴法研究马拉硫磷、溴氰菊酯在亚致死剂量(100h-LD30)下对亚洲玉米螟Ostrinia furnacalis雌蛾性信息素通讯系统的干扰作用。试验结果表明：①点滴当天雌蛾的求偶百分率分别下降为对照的50％、33％，但求偶高峰期出现的时间未受影响。②点滴这两种药剂后求偶百分率的恢复过程相当缓慢。③亚致死剂量的马拉硫磷使性信息素的量下降1／2左右，亚致死剂量的溴氰菊酯使性信息素量下降为不足对照的1／4，但性信息素顺反异构体比例均不受影响。④马拉硫磷点滴后第4天性信息素量能完全恢复，但溴氰菊酯点滴后，到第4天仍几乎不能恢复。     

Toxicity and sublethal effects of an insecticidal soap on Aphidius colemani (Hymenoptera: Braconidae)

BACKGROUND: The effects of an insecticidal soap on the survival, fitness and behaviour of an aphid parasitoid wasp, Aphidius colemani (Viereck), were studied in the laboratory. The LC(50) (soap concentration causing 50% mortality 24 h after treatment) was determined. The survival of parasitoid larvae (% adult emergence), fitness (tibia length of adults) and number of eggs produced per female parasitoid that survived in third- and fourth-instar aphids treated with insecticidal soap LC(50) were also assessed. The LC(50) for third- and fourth-instar aphids was determined to be 3.25 g L(-1). Acceptance by female parasitoids of aphids that survived their LC(50) was also tested. RESULTS: The soap concentration causing 100% mortality in adult wasps 24 h after treatment was 17.5 g L(-1). The LC(50) was 2.75 g L(-1). Soap did not have any effect on the survival of parasitoid immatures or on the fitness or number of eggs produced per female parasitoid. Wasps that were in contact with treated aphids did not oviposit as much in them as in untreated aphids, indicating that female parasitoids detected aphids treated with insecticidal soap. CONCLUSION: These data suggest that aphid parasitoids released following treatment with insecticidal soap are likely to accept a lower proportion of the surviving aphids. Biological control programmes could be ameliorated by soap applications if the latter were made 1 day before the release of wasps in the greenhouse.     

白花丹根提取物的杀螨活性

研究了白花丹Plumbago zeylanica L. 根提取物对柑桔全爪螨的杀螨活性,发现其具有优良的杀螨、杀卵和产卵抑制活性.白花丹根先经甲醇冷浸提取,然后用石油醚萃取甲醇提取物,所得石油醚萃取物的12、24h杀螨致死中浓度(LC50)分别为2.52、2.12mg/ml, 产卵抑制中浓度(ODC50)分别为1.39、1.52mg/ml,杀卵LC50为1.04mg/ml.石油醚萃取物经硅胶柱层析后,以PE5-9馏份的活性最高,1mg/ml浓度下,杀螨率和杀卵率与白花丹素(plumbagin)标样在P=0.05水平均无显著差异.PE5-9馏份 12、24h的杀成螨LC50分别为0.71、0.67mg/ml,杀卵LC50为0.66mg/ml.不同溶剂展开系统薄层层析和GC-MS结果表明,该植物中的杀螨活性主要成分为白花丹素.     

Role of a microsomal carboxylesterase in reducing the action of malathion in eggs of Triatoma infestans

A microsomal malathion carboxylesterase present in Triatoma infestans eggs was active from the first day of embryonic development. This microsomal egg malathionase (MEM) showed a unique band in polyacrilamide gel electrophoresis (PAGE) when malathion was used as substrate. In vivo metabolism of [¹⁴C]malathion during all embryonic development showed a 10% degradation due to carboxylesterases. The in vitro evaluation of the same metabolic pathway catalyzed by the microsomal fraction of T. infestans eggs showed partial inhibition by paraoxon. α- and β-malathion monoacids were identified as the main metabolites of the in vivo and in vitro metabolic pathways. The carboxylesterase band that appeared in PAGE (MEM) from the first day of embryonic development could be the main cause of malathion tolerance in T. infestans eggs.     

两种花粉对巴氏钝绥螨生长发育与繁殖的影响

在实验室条件下测定了两种花粉对巴氏钝绥螨生长发育与繁殖的影响。结果表明,在温度25 ℃、相对湿度72%,光照L∥D=12 h∥12 h条件下,油菜花粉饲养的巴氏钝绥螨幼螨、前若螨、后若螨历期分别为0.98、3.23、430 d。幼螨发育到成螨共需8.52 d,存活率为83.33%,雌虫不产卵。丝瓜花粉饲养的巴氏钝绥螨卵、幼螨、前若螨、后若螨、产卵前期、世代历期分别为2.55、0.97、2.38、2.07、3.20、11.17 d。平均每头雌螨日产卵量1.78粒,总产卵量58.60粒,产卵持续时间33.53 d,无不产卵个体。其日产卵量呈二次抛物线趋势,回归方程为y=0.155 4t-0.002 80t2(R2=0.951 5,p<0.000 1)。取食丝瓜花粉的巴氏钝绥螨的种群趋势指数I=28.13,净生殖率为R0=26.813,种群平均世代周期T=30.139 d,内禀增长率rm=0.109,周限增长率λ=1.115,种群加倍时问t=6.352 d。由以上试验结果可知,丝瓜花粉比油菜花粉更适合饲养、繁殖巴氏钝绥螨。     

喹硫磷在茶叶中的残留降解

在杭州和长沙两地两年用不同剂量、不同施药方法进行的研究表明,喹硫磷在茶树鲜叶上降解速度中等,1天后的降解率平均7.15％,降解速度低于辛硫磷、马拉硫磷、敌敌畏等农药。用25％乳剂800倍液喷施后5天鲜叶中残留量低于10ppm,10天后低于1ppm,降解速率常数(K)0.47±0.06天,半衰期1.37±0.02天。降雨对喹硫磷在茶树上的降解有一定影响,尤其在施药后的近期。对成茶中在喷后不同间隔天数的残留量、含喹硫磷残留的鲜叶在加工过程中的降解率、成茶中喹硫磷残留量在泡茶时的浸出率,均进行了测定,并讨论了喷后不同间隔期鲜叶上的残留量和茶尺蠖幼虫致死剂量间的关系。建议喹硫磷在成茶中允许残留标准暂订为0.2ppm,茶叶喷施25％乳油800倍液后的安全间隔期为8—10天。     

二点委夜蛾形态特征及生物学特性

二点委夜蛾是近年来我国夏玉米上发现的一种新害虫,目前在我国玉米产区有加重为害和成灾的趋势。为便于田间准确识别该虫、调查其发生为害规律以及掌握其主要生物学特性,在室内对二点委夜蛾不同发育阶段的形态特征和主要生物学特性进行了系统观测。结果表明,在温度为(26±1)℃、相对湿度70%左右、光周期L14 h∥D10 h、人工饲料饲养条件下,二点委夜蛾卵期平均为4.25 d;幼虫一般为5龄,幼虫期平均为18.28 d;蛹期平均为7.69 d,蛹重平均可达75.77 mg;成虫产卵前期平均为3.29 d,产卵可持续9.13d,平均每雌产卵量为305.3粒,最多产500粒,最少132粒。雌雄蛾平均寿命分别为14.75 d和18.88 d。整个世代发育历期约为33.35 d。     

甲氰菊酯和螺螨酯对二斑叶螨实验种群的亚致死效应

在室内研究了甲氰菊酯和螺螨酯亚致死剂量对二斑叶螨实验种群成螨和卵的影响。结果表明,甲氰菊酯亚致死剂量LC10处理成螨后,二斑叶螨的卵期、幼螨期、若螨期、成螨期及寿命均显著缩短,处理卵后各发育历期均显著低于对照;亚致死剂量LC20处理成螨后二斑叶螨的卵期、若螨期、成螨期及寿命均显著缩短,处理卵后各发育历期均低于对照,处理后F1代种群的内禀增长率rm由0.191 9增至0.193 4～0.205 9,对种群有刺激增殖作用。螺螨酯亚致死剂量LC10处理成螨后,卵期、若螨期显著延期长,处理卵后卵期、若螨期、产卵前期均长于对照;亚致死剂量LC20处理成螨后卵期、幼螨期显著延长,处理卵后卵期、若螨期、产卵前期均长于对照,螺螨酯两亚致死剂量处理成螨和卵后成螨期和寿命均缩短,处理后F1代种群的内禀增长率rm由0.191 9降低至0.149 9～0.150 8,对种群有抑制作用。     

两种药剂亚致死浓度对麦长管蚜实验种群参数的影响

为明确阿维·吡虫啉和氯氟·吡虫啉两种复配制剂对麦长管蚜Sitobion miscanthi种群数量动态的影响,采用生命表技术分别研究了两种药剂亚致死浓度LC10、LC30对麦长管蚜F0代和F1代生长发育及种群参数的影响.结果 表明,阿维·吡虫啉和氯氟·吡虫啉LC10、LC30处理后,与对照相比,麦长管蚜F0代成蚜寿命和...     

七星瓢虫的抗药性选育及其生物学特性研究

为了明确七星瓢虫对吡虫啉的抗性发展动态,在室内选用吡虫啉逐代筛选,选育抗吡虫啉的七星瓢虫品系。发现七星瓢虫对吡虫啉的抗性整体呈上升趋势,但抗性不稳定,选育20代后抗性为63.1519倍。同时为了明确七星瓢虫对吡虫啉产生抗性后对其生物学特性的影响,将抗性选育13代的七星瓢虫品系与敏感七星瓢虫品系、野外七星瓢虫种群进行生物学特性的比较,结果表明,从幼虫的整个发育历期来观察,抗性品系幼虫的发育历期为12.36 d,野外种群为9.88 d,敏感品系为10.62 d,3者之间差异显著;蛹发育历期3者之间没有差异;4龄老熟幼虫、蛹、初羽化雌成虫、初羽化雄成虫平均体重3组间有一定的差异;七星瓢虫抗性品系、敏感品系、野外种群前期的卵孵化率分别为63.0%、62.4%和66.3%,中期的卵孵化率分别为64.8%、58.7%和75.6%,后期的卵孵化率分别为69.3%、57.4%和75.5%,3组之间无显著差异;抗性品系雌成虫的平均产卵量为1043.3粒,敏感品系为1100.2粒,野外种群雌成虫为1250.1粒,3者之间没有显著差异。综上所述,抗药性对七星瓢虫的生物适合度有一定程度的影响,但是,由于抗性倍数较低,影响尚不明显。     

胡瓜新小绥螨对B型烟粉虱的控制能力

为明确胡瓜新小绥螨Neoseiulus cucumeris Oudermans对烟粉虱Bemisia tabaci Gennadius的控害潜能,在（26±1）℃、相对湿度65%±5%、光周期16L：8D条件下,研究了各螨态胡瓜新小绥螨对不同发育阶段烟粉虱的捕食作用。结果表明,胡瓜新小绥螨幼螨期较短,不取食烟粉虱,其他不同螨态的胡瓜新小绥螨可捕食除4龄若虫和成虫以外的其他各虫态的烟粉虱,捕食功能反应符合HollingⅡ型;胡瓜新小绥螨雌成螨对烟粉虱卵的日捕食量最大（8.5粒/雌）,对烟粉虱3龄若虫的日捕食量最小（2.1头/雌）;雌成螨对烟粉虱卵具有较高的瞬间攻击率（0.038）和寻找效应（0.025）。研究表明,胡瓜新小绥螨对烟粉虱卵及低龄若虫的捕食能力较强,是烟粉虱发生初期的有效天敌。