3种环境友好型药剂对西花蓟马的室内毒力与田间防效

测定了3种杀虫剂对西花蓟马的室内毒力和田间防效。室内生物测定结果表明,多杀菌素、甲氨基阿维菌素苯甲酸盐、阿维菌素对西花蓟马成虫的LC50值为0.050～2.887mg/L,对西花蓟马若虫的LC50值为0.040～0.457mg/L;田间药效试验表明,田间防治西花蓟马时推荐使用剂量(防效>80%)分别为:2.5%多杀菌素悬浮剂30～60g/667m2,1%甲氨基阿维菌素苯甲酸盐乳油30～60g/667m2,1.8%阿维菌素乳油不可低于75g/667m2。     

不同光照条件对西花蓟马产卵量的影响

在人工气候培养箱中,温度(28±1)℃,相对湿度(70±5)%条件下,研究了不同光照强度及光周期对西花蓟马产卵量的影响。结果表明,西花蓟马孤雌生殖与两性生殖的繁殖力最适光照强度不同。西花蓟马在10 000 lx时孤雌生殖的产卵量最高,两性生殖的最高产卵量则出现在20 000 lx时。初步明确了光照条件对西花蓟马的繁殖方式有明显影响。孤雌生殖状态下,光周期对西花蓟马总产卵量无显著影响;在所有光周期下24 h均无明显产卵高峰;光照时段单位时间产卵量在光周期之间无显著差异。但黑暗时段单位时间产卵量在光周期之间存在显著差异,L//D=16h//8h时最多,L//D=12h//12h时最少;L//D=12h//12h时,光照时段单位时间产卵量显著高于黑暗时段。其他两个光周期下光照时段和黑暗时段单位时间产卵量均无显著差异。两性生殖状态下,光周期对西花蓟马产卵总量影响显著。L//D=12h//12h显著高于其他两个光周期;光周期为L//D=12h//12h时,光照时段10∶00-12∶00时有一个明显的产卵高峰,其他两个光周期均无明显产卵峰值。光照时段单位时间产卵量在光周期之间存在显著差异,L//D=12h//12h显著高于其他两个光周期。但黑暗时段单位时间产卵量在光周期之间无显著差异。所有光周期下光照时段与黑暗时段单位时间产卵量均无显著差异。     

低剂量杀虫剂与高温结合对西花蓟马种群的防控

为了探究低剂量杀虫剂与高温结合防控西花蓟马Frankliniella occidentalis种群的最佳组合,选用啶虫脒、多杀菌素、高效氯氰菊酯和灭多威4种杀虫剂的LC_(50)剂量处理西花蓟马成虫和2龄若虫18~76 h后,分别在41、43、45℃进行2 h热激处理,观察并记录每种组合下西花蓟马的存活情况。结果表明,药剂处理成虫或若虫18 h和28 h后再进行热激处理,西花蓟马的存活率显著低于其它处理。经4种杀虫剂的LC_(50)剂量处理后,不同高温热激均能不同程度降低成虫或若虫种群存活率,热激后存活率显著低于对照组;经灭多威LC_(50)剂量处理的成虫或若虫,再经高温热激处理后的存活率最低,其中45℃热激处理对成虫和若虫的存活率影响最明显,经45℃热激处理18 h和28 h后的成虫存活率为10.1%和5.9%,若虫存活率为6.1%和3.3%。研究表明,杀虫剂LC_(50)剂量与高温热激联合增强了对西花蓟马种群的抑制作用,药剂处理后选择最佳热激时间可最大限度降低西花蓟马的耐热性,进一步增强高温热激的防治效果。     

多杀菌素低剂量处理西花蓟马对药剂敏感性的影响

用低剂量多杀菌素继代处理西花蓟马(Frankliniella occidentalis)40多代后,测定了处理种群对其他5种不同类型杀虫剂的敏感性。结果表明,西花蓟马用多杀菌素LC25的浓度继代处理,对多杀菌素的敏感性逐渐下降。处理47代后,该种群的LC50是敏感种群的6.7倍,达到了低水平抗性。在第41代,当处理种群对多杀菌素的敏感性下降为敏感种群的5.19倍时,对阿维菌素和甲氨基阿维菌素苯甲酸盐的敏感性也下降,分别为敏感种群的2.68倍和2.92倍。     

球孢白僵菌对西花蓟马成虫的毒力及体表侵染的扫描电镜观察

本文在室内测定球孢白僵菌Beauveria bassiana CYT4菌株对西花蓟马Frankliniella occidentalis成虫的致死作用,并电镜观察分生孢子在西花蓟马成虫体表的侵染过程。结果表明：白僵菌的致死率随孢子浓度的增加而增加,1×109、1×108、1×107和1×106孢子.mL-1的孢悬液接种试虫第6d的致死率分别为83.57%、66.08%、49.78%和20.22%;0.04μL.mL-1和0.06μL.mL-1的多杀菌素与1×108孢子.mL-1白僵菌孢悬液混合后对试虫接种第5d的致死率分别为89.42%和95.76%,而单独施用菌液为58.19%,单独施用多杀菌素仅为45.55%和61.33%,表明二者混合能提高对西花蓟马成虫的致死率。扫描电镜观察发现,经白僵菌孢悬液处理的西花蓟马成虫虫体,在触角基节、复眼、足部褶皱区、刚毛窝、翅、产卵器和各体节连接处均有大量孢子附着和萌发,但腹部孢子量很少,尤其在节间膜处几乎无孢子;孢子在1h时即附着在体表,12h时已萌发,36h时有穿透体壁现象,48h后整个虫体被菌丝包被。     

室内药剂交替使用对西花蓟马抗药性发展的影响

分别单独使用毒死蜱、多杀菌素和两种农药交替使用连续处理西花蓟马(Frankliniella occidentalis)18代,采用浸渍法从第6至第18代每隔2世代测定3个汰选种群对毒死蜱和多杀菌素的敏感性.结果表明,毒死蜱和多杀菌素交替汰选种群比单一药剂连续汰选种群抗性上升趋势缓慢,F18代时交替使用汰选种群对毒死蜱和多杀菌素的抗性倍数分别为10.89倍和17.19倍,而毒死蜱单一汰选种群对毒死蜱的抗性倍数达到24.19倍,多杀菌素单一汰选种群对多杀菌素的抗性倍数达到20.78倍.因此,交替或轮换使用药剂可以延缓西花蓟马抗药性的发展.     

日光温室防治棕榈蓟马药剂筛选

采用浸叶法开展了7种杀虫剂对温室棕榈蓟马成虫的室内毒力测定,并对效果较好的2种药剂进行田间药效试验。室内生物测定结果表明,多杀菌素、甲氨基阿维菌素苯甲酸盐对棕榈蓟马成虫的LC50分别为0.079 mg/L 和0.443 mg/L,而阿维菌素、灭多威、啶虫脒、高效氯氟氰菊酯LC50值为47.908 ~206.236 mg/L。田间药效试验结果表明,2.5%多杀菌素悬浮剂和2.2%甲氨基阿维菌素苯甲酸盐微乳剂使用剂量以80~60 g/667 m2和 30~20 g/667 m2防治效果较理想。     

不同温度下巴氏新小绥螨对西花蓟马初孵若虫的捕食功能

为明确巴氏新小绥螨[Neoseiulus barkeri(Hughes)]对西花蓟马[Frankliniella occidentalis(Pergande)]初孵若虫的捕食效应,在相对湿度RH 85%±5%,5个温度梯度16、20、24、28、32℃,光照L∥D=16h∥8h条件下选取西花蓟马的初孵若虫进行捕食功能反应。结果表明:巴氏新小绥螨对西花蓟马初孵若虫的捕食功能反应属于HollingⅡ型方程。在16~28℃温度范围内,巴氏新小绥螨对西花蓟马初孵若虫的攻击系数、捕食能力、最大日捕食量均随温度升高而增加,处理时间则缩短,28℃时日捕食量最高达14.471 8头,处理时间最短为0.069 1d。温度达到32℃时,捕食量下降。当西花蓟马初孵若虫的种群密度一定时,巴氏新小绥螨的平均捕食量随其自身密度的增加而降低。说明猎物密度固定时巴氏新小绥螨存在明显的相互干扰作用。     

西花蓟马抗药性研究进展

西花蓟马是世界范围内蔬菜和花卉上的重要害虫之一,使用化学药剂是防治西花蓟马的主要手段,目前西花蓟马已对有机氯、有机磷、氨基甲酸酯、拟除虫菊酯、阿维菌素和多杀菌素等多种杀虫剂产生了抗药性。本文从抗药性现状、抗性机制和抗性治理等几个方面介绍了国内外有关西花蓟马抗药性的研究进展。     

西花蓟马取食、机械损伤和外源物质诱导对番茄植株次生物质及西花蓟马解毒酶的影响

为阐明寄主植物番茄受害虫西花蓟马Frankliniella occidentalis取食、机械损伤及外源物质茉莉酸和水杨酸甲酯诱导后次生物质含量的变化,以及害虫如何通过调整体内解毒酶活性适应植物的防御反应,采用生化分析法测定了各诱导处理下次生物质黄酮、总酚和单宁含量及西花蓟马体内解毒酶多功能氧化酶(MFO)、乙酰胆碱酯酶(AchE)、谷胱甘肽S-转移酶(GSTs)和羧酸酯酶(CarE)活性的变化。结果表明:番茄叶片在各诱导处理下黄酮含量在36 h和48 h时均显著高于对照,相应时间段茉莉酸处理与水杨酸甲酯处理的黄酮含量升高最显著,分别达32.07 mg/g和31.76 mg/g;各诱导处理后24 h和36 h时,单宁和总酚含量均有不同程度下降,但总酚含量在48 h时显著升高,其中虫害处理增加最显著,达34.51 mg/g。取食各种诱导处理番茄植株6 h时,西花蓟马体内MFO活性均升高,AchE活性均受到抑制;取食除机械损伤外的其它诱导处理叶片6 h后,西花蓟马体内GSTs活性均被抑制,CarE活性均显著上升,其中取食水杨酸甲酯处理叶片的西花蓟马体内GSTs活性下降幅度最大,而CarE活性升高最显著,分别为3 882.35 U/mg和106.33 U/mg。表明各诱导处理不仅可以使番茄次生物质含量发生变化,诱导植株产生防御反应,也会使西花蓟马改变解毒酶的活性以适应寄主植物的诱导抗性,即寄主植物和害虫通过防御与反防御相互适应。     

Resistance to spinosad in the western flower thrips, Frankliniella occidentalis (Pergande), in greenhouses of south-eastern Spain

Susceptibility to spinosad of western flower thrips (WFT), Frankliniella occidentalis (Pergande), from south-eastern Spain was determined. LC(50) values of the field populations without previous exposure to spinosad collected in Murcia in 2001 and 2002 ranged from 0.005 to 0.077 mg L(-1). The populations collected in Almeria in 2003 in greenhouses were resistant to spinosad (LC(50) > 54 mg L(-1)) compared with the authors' highly susceptible laboratory strain. The highly sensitive laboratory strain leads to very high resistance ratios for the field populations (>13 500), but these ratios do not necessarily mean resistance problems and control failures (spinosad field rate 90-120 mg L(-1)). The populations collected in Murcia from some greenhouses in 2004 were also resistant to spinosad (RF > 3682). Spinosad overuse, with more than ten applications per crop, produced these resistant populations in some greenhouses. Spinosad showed no cross-resistance to acrinathrin, formetanate or methiocarb in laboratory strains selected for resistance towards each insecticide. Correlation analysis indicated no cross-resistance among spinosad and the other three insecticides in 13 field populations and in nine laboratory strains. The synergists piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM) did not enhance the toxicity of spinosad to the resistant strains, indicating that metabolic-mediated detoxification was not responsible for the spinosad resistance. These findings suggest that rotation with spinosad may be an effective resistance management strategy.     

Note: Systemic effects of a spinosad insecticide onLiriomyza huidobrensis Larvae

In an effort to expand the spectrum of larvicides effective againstLiriomyza huidobrensis (Blanchard), the effect of spinosad was studied on the mortality of the leafminer under laboratory conditions. Bean plants infested with various leafminer stages (egg through third instar) were treated by dipping leaves in a liter of water containing 24, 48 or 96 mg a.i. spinosad or by drenching the soil of plants with 200 ml of water containing 12 mg, 24 mg or 48 mg a.i. spinosad. In general, leaf dipping was more efficacious and adverse effects were observed sooner than with soil drench. All concentrations of spinosad significantly reduced the number of adults that emerged except leaf dip of third instar; only the highest concentration caused significant reduction of pupae and adults. Spinosad would likely be a valuable insecticide for control of the pea leafminer,L. huidobrensis. http://www.phytoparasitica.org posting Nov. 4, 2005.     

中红侧沟茧蜂亲代经历对子代滞育的影响

在室内条件下,研究了中红侧沟茧蜂亲代经历不同温度及光周期条件对其子代滞育的影响。设置亲代经历的不同环境条件分别为：①在23℃下中红侧沟茧蜂成蜂经历L∶D=0h∶24h、4h∶20h、8h∶16h、12h∶12h、16h∶8h、20h∶4h、24h∶0h七种不同光周期处理;②亲代经历3种不同温度（16℃2、0℃、24℃）和3种不同光周期（L∶D=10h∶14h、12h∶12h、14h∶10h）的组合处理;③不同日龄滞育茧蜂与发育茧蜂的成蜂寄生寄主粘虫。其子代在3种不同温度（16℃、20℃、24℃）和光周期L∶D=10h∶14h、12h∶12h、14h∶10h下饲养,观察子代的滞育率变化情况。结果表明：在环境温度为23℃时,成蜂经历不同光周期可显著影响子代的滞育率;亲代经历不同的光周期与温度也可显著影响子代的滞育率;交配后不同日龄的成蜂寄生寄主粘虫对其子代的滞育率影响不显著。在中红侧沟茧蜂的生活史中,温度与光周期的共同作用可影响其子代滞育的产生,亲代经历在子代滞育过程中起一定的作用,但能否进入滞育还是由其子代的环境条件来决定。     

基于冠层叶-气温差的温室土壤水分诊断

根据对日光温室条件下番茄全生育期的冠层温度、气温、土壤水分以及一些相关气象因素测定,分析了冠层叶-气温差与土壤容积含水率、湿度之间的关系。结果表明:在日光温室条件下,番茄全生育期内冠层叶-气温差的日变化呈曲线分布,冠层叶-气温差的最高值出现在每天的13∶00～15∶00之间。通过对主要生育期13∶00～15∶00的数据分析发现,冠层叶-气温差(△T)与土壤容积含水率(SW)以及棚内湿度(RH)之间有较好的复相关关系,结合容积含水率与湿度对冠层叶-气温差的综合影响,可以得出△T与SW呈负相关关系,与RH呈正相关关系,相关系数R2为0.778。通过偏相关分析,冠层叶-气温差与容积含水率的相关性最大,呈负相关关系,相关系数R2为0.778,并通过数据验证,实测值(Y)与模拟值(X)相关性较好,相关系数R2为0.723。因此可通过监测13∶00～15∶00的冠层叶-气温差来了解作物的水分状况,为农田土壤水分诊断提供科学依据。     

Effect of temperature,relative humidity,leaf wetness and leaf age on <Emphasis Type="Italic">Spilocaea oleagina</Emphasis> conidium germination on olive leaves

The effects of temperature, relative humidity (RH), leaf wetness and leaf age on conidium germination were investigated for Spilocaea oleagina, the causal organism of olive leaf spot. Detached leaves of five ages (2, 4, 6, 8 and 10 weeks after emergence), six different temperatures (5, 10, 15, 20, 25 and 30°C), eight wetness periods (0, 6, 9, 12, 18, 24, 36 and 48 h), and three RH levels (60, 80 and 100%) were tested. Results showed that percentage germination decreased linearly in proportion to leaf age (P < 0.001), being 58% at 2 weeks and 35% at 10 weeks. A polynomial equation with linear term of leaf age was developed to describe the effect of leaf age on conidium germination. Temperature significantly (P < 0.001) affected frequencies of conidium germination on wet leaves held at 100% RH, with the effective range being 5 to 25°C. The percent germination was 16.1, 23.9, 38.8, 47.8 and 35.5% germination at 5, 10, 15, 20 and 25°C, respectively, after 24 h. Polynomial models adequately described the frequencies of conidium germination at these conditions over the wetness periods. The rate of germ tube elongation followed a similar trend, except that the optimum was 15°C, with final mean lengths of 175, 228, 248, 215 and 135 μm at 5, 10, 15, 20 and 25°C, respectively after 168 h. Polynomial models satisfactorily described the relationships between temperature and germ tube elongation. Formation of appressoria, when found, occurred 6 h after the first signs of germination. The percentage of germlings with appressoria increased with increasing temperature to a maximum of 43% at 15°C, with no appressoria formed at 25°C after 48 h of incubation. Increasing wetness duration caused increasing numbers of conidia to germinate at all temperatures tested (5–25°C). The minimum leaf wetness periods required for germination at 5, 10, 15, 20 and 25°C were 24, 12, 9, 9 and 12 h, respectively. At 20°C, a shorter wetness period (6 h) was sufficient if germinating conidia were then placed in 100% RH, but not at 80 or 60%. However, no conidia germinated without free water even after 48 h of incubation at 20°C and 100% RH. The models developed in this study should be validated under field conditions. They could be developed into a forecasting component of an integrated system for the control of olive leaf spot.     

10种杀虫剂对4种蓟马的毒力及对西花蓟马的田间药效评价

蓟马对农作物的危害逐年加重, 为筛选防治蓟马的高效低毒药剂, 采用叶管药膜法测定了10种常用药剂对4种蓟马的室内毒力, 并开展了田间防效试验。室内毒力测定结果表明, 6%乙基多杀菌素SC和10%虫螨腈SC对4种蓟马的毒力相对较高, 25%噻虫嗪WG和5%甲维盐EC的毒力较低, 西花蓟马和瓜蓟马对10种药剂的敏感性低于花蓟马和烟蓟马。田间药效结果表明, 25%噻虫嗪WG、10%溴虫氟苯双酰胺SC和4.5%高效氯氰菊酯EC对西花蓟马的防效较高, 药后7 d药效最高达到90%以上。综合室内毒力和田间药效试验结果, 推荐4.5%高效氯氰菊酯EC和10%溴虫氟苯双酰胺SC为防治蓟马的首选药剂, 可与25%噻虫嗪WG、48%多杀霉素SC、1.8%阿维菌素EC和10%吡丙醚SC等药剂轮换使用。     

Susceptibility to thiamethoxam of Musca domestica from Danish livestock farms

BACKGROUND: Neonicotinoid baits are currently replacing anticholinesterase baits for control of adult houseflies (Musca domestica L.). Introduction of new insecticides includes evaluation of their cross-resistance potential, which was assessed for thiamethoxam in field populations from Denmark. RESULTS: In feeding bioassay with a susceptible strain, thiamethoxam LC(50) at 72 h was 1.7 microg thiamethoxam g(-1) sugar, making it 19-fold, 11-fold and threefold more toxic to houseflies than azamethiphos, methomyl and spinosad respectively. The field populations were 6-76-fold resistant to thiamethoxam. There was no correlation between the toxicities of thiamethoxam and spinosad, dimethoate, methomyl, bioresmethrin or azamethiphos. The toxicity in feeding bioassay at 72 h of imidacloprid in a susceptible strain was 32 microg imidacloprid g(-1) sugar at LC(50), making it 19-fold less toxic to houseflies than thiamethoxam. There was a strong significant correlation between the toxicities of thiamethoxam and imidacloprid in field populations.CONCLUSION: Neonicotinoid-resistant houseflies were present at a detectable and noticeable level before thiamethoxam and imidacloprid were introduced for housefly control in Denmark. The toxicity of thiamethoxam is explained by other parameters than the toxicities of spinosad, dimethoate, methomyl, bioresmethrin or azamethiphos. The cross-resistance between thiamethoxam and imidacloprid indicates a coincidence of mechanism of the toxicity and resistance in the field populations.