亚致死浓度多杀菌素对西花蓟马解毒酶系活力的影响

采用亚致死浓度(LC25)多杀菌素对西花蓟马Frankliniella occidentalis相对敏感(SS)种群进行连续选育,获得亚致死(Sub)种群。处理36代后,Sub种群对多杀菌素的敏感性下降到SS种群的5.2倍。用SS和Sub种群各自的LC10和LC25浓度多杀菌素分别处理两种群的2龄若虫,1、6 、12、24和48 h后测定羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GSTs) 和多功能氧化酶(MFOs)的比活力。结果表明,Sub种群对照组CarE和GSTs比活力在除第48 h外的其他时间段都高于SS种群对照组,且6 h时两者CarE比活力差异显著,Sub种群是SS种群的1.37倍;Sub种群对照组MFOs比活力在各时间段都高于SS种群对照组,在1 和6 h时差异显著,前者分别是后者的1.62和1.36倍。再经各自的LC10和LC25浓度多杀菌素处理后,在各时间段Sub种群的CarE比活力均高于SS种群;LC25浓度处理后,Sub种群的GSTs和MFOs比活力虽在短时间内低于SS种群,但随处理时间的延长其比活力均高于SS种群。说明SS种群经亚致死浓度多杀菌素选育36代后,其体内CarE、GSTs和MFOs比活力有上升趋势;继续用亚致死浓度多杀菌素处理,则Sub种群体内解毒酶活力的动态调节能力要强于SS种群。     

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.     

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。     

外源茉莉酸和水杨酸甲酯对西花蓟马生长发育和种群动态的影响

为明确不同外源因子对菜豆的诱导抗性及对西花蓟马的影响, 研究了茉莉酸、水杨酸甲酯、西花蓟马为害、机械损伤诱导处理的菜豆对西花蓟马生长发育和种群动态的影响。结果表明外源茉莉酸、水杨酸甲酯、西花蓟马为害处理菜豆植株显著延长了西花蓟马未成熟期的发育时间, 较健康植株分别延长4.72、2.87和4.95 d, 也造成西花蓟马的存活率不同程度的下降。西花蓟马在机械损伤处理和健康植株发育时间差异不显著。不同处理均使西花蓟马种群数量明显下降, 并且茉莉酸的抑制作用最明显。因此, 外源茉莉酸和水杨酸甲酯诱导的菜豆可对西花蓟马生长发育和种群动态产生不同程度的影响, 且茉莉酸的诱导抗性要优于水杨酸甲酯。本结果对探索西花蓟马的防治新策略有一定的参考价值。     

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。     

辣椒开花对西花蓟马种群的影响

为揭示寄主植物开花与否对西花蓟马种群增长的作用,研究了辣椒是否有花对不同密度下西花蓟马种群数量的影响。结果显示,开花辣椒上的西花蓟马种群数量明显高于无花辣椒,在接入30头/株密度下,7 d、14 d、21 d和28 d 4个时间段开花辣椒上西花蓟马种群数量分别是未开花的2.3倍、1.5倍、1.8倍和2.5倍;15头/株密度下,开花辣椒上种群数量是未开花的2.0倍、1.3倍、1.5倍和1.7倍。结果表明,开花的辣椒植株对西花蓟马种群数量的增长有明显的促进作用。     

高温处理西花蓟马若虫对其雌成虫寿命、繁殖力及后代发育的影响

温度是影响昆虫生长发育的重要生态因素之一,高温逆境作为一种绿色防控手段可以有效控制温室害虫种群发展。为了探究高温处理西花蓟马若虫对其种群发展的影响,本试验用41℃和43℃两个温度分别处理西花蓟马初孵若虫2、6、12、24和36h后,观察并记录其雌成虫寿命、繁殖力及后代发育指标的变化情况。结果表明,随着处理时间的延长,两个高温处理后西花蓟马雌成虫寿命,子代若虫总数、成虫总数和总存活率(若虫发育到成虫的存活率)均显著下降,后代雌雄性比呈总体下降趋势。41℃处理后,性比从2.30∶1降低到2.13∶1;43℃处理后从2.25∶1降低到2.07∶1,均明显低于对照的2.69∶1。另外,两性生殖种群相比于孤雌生殖种群更易遭受高温处理的影响。     

张家口地区田间小菜蛾种群对6种新型杀虫剂的敏感性测定

用浸液法测定了河北省张家口地区田间小菜蛾种群对氯虫苯甲酰胺等几种新型杀虫剂的敏感性。田间小菜蛾种群对甲氨基阿维菌素苯甲酸盐、多杀菌素、茚虫威、氯虫苯甲酰胺、三氟甲吡醚、氰氟虫腙等的抗性倍数分别为5.19、2.22、0.25、1.07、1.16和0.92倍。敏感性测定结果表明,田间种群对甲氨基阿维菌素苯甲酸盐产生了低水平抗性,对多杀菌素、氯虫苯甲酰胺、三氟甲吡醚未产生明显抗药性,对茚虫威、氰氟虫腙相当敏感。     

环境因子对西花蓟马室内生物测定结果的影响

采用Munger cell法,就室内测定多杀菌素对西花蓟马 Frankliniella occidentalis 生物活性实验中需要控制的温度、相对湿度、滴水量、光周期、光照度和叶片6个环境条件对测定结果的影响进行了研究。发现:在25 ~30 ℃、相对湿度50% ~70%、光周期(L:D)为16 h:8 h~24 h:0 h、光照度6 500~13 000 lx这一测定条件范围内,采用月季、西葫芦、萝卜、芸豆、苹果、芹菜、菠菜叶片进行生物测定时结果较稳定;叶片纤毛数量与多杀菌素对西花蓟马的LC50值成负相关,相关系数为0.919;叶片纤毛的长度则与测定结果无相关性。     

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。     

多杀菌素亚致死浓度对小菜蛾解毒酶系活力的影响

采用多杀菌素亚致死浓度,以浸叶法分别处理小菜蛾Plutella xylostella (L.)敏感种群(SS)和亚致死选育种群 的3龄幼虫,分别测定饲喂处理6、12、24、48和72 h后小菜蛾体内羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GST) 和多功能氧化酶(MFOs)的活性,分析了酶活性的变化动态。结果表明,SS种群小菜蛾CarE的活性在不同时间段波动较大,经多杀菌素处理后,开始时段比活力增加,随着处理时间的延长,比活力逐渐被抑制,Sub-SS种群的GarE活力高于SS种群;多杀菌素对GST具有明显的诱导作用,亚致死浓度处理后GSTs比活力呈上升趋势,且具有一定的时间效应;对细胞色素P450酶系的O-脱甲基酶活性具有明显的抑制作用,多杀菌素亚致死浓度连续处理5代后,该酶活性更低。     

Monitoring of beet armyworm resistance to spinosad and methoxyfenozide in Mexico

BACKGROUND: Resistance to spinosad and methoxyfenozide has been studied in several insect pests, but there is a lack of information on Spodoptera exigua (Hübner) in Mexico. Therefore, evidence for the development of resistance in this pest to both compounds was examined. The effects of methoxyfenozide on reproductive parameters of S. exigua adults were also determined.RESULTS: Third instars from a field population were exposed for 24 h to the LC(50) of spinosad or methoxyfenozide for over six generations (G(2)-G(7)). No significant reduction in susceptibility to either compound was detected for up to five generations. In G(7), LC(50) values for insects exposed to spinosad and methoxyfenozide were respectively 2.75-fold and 1.25-fold greater than for G(1) larvae. Oral treatment with methoxyfenozide reduced the fecundity and fertility of G(7) adults, confirming sublethal effects on reproduction. Finally, five populations (Se-La Floriza, Se-Lazareto, Se-Bachigualato, Se-Los Agustinos and Se-Villa de Arista) of S. exigua were collected from fields in three states of Mexico for resistance monitoring to spinosad and methoxyfenozide. With the exception of Se-Villa de Arista, the other populations showed significant resistance to spinosad, with resistance ratios between 16- and 37-fold, compared with a susceptible laboratory colony. In contrast, only one population (Se-Lazareto) showed significant resistance to methoxyfenozide (13-fold).CONCLUSION: Resistance management programmes should be established, particularly in areas where S. exigua has developed resistance to spinosad. Copyright (c) 2008 Society of Chemical Industry.     

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.     

Beet armyworm (Spodoptera exigua) resistance to spinosad

Susceptibility to spinosad (Success®/Tracer®) of beet armyworm (Spodoptera exigua) from the southern USA and Southeast Asia was determined through exposure of second‐ and third‐instar larvae to dipped cotton leaves. LC₅₀ estimates of susceptibility of second‐ and third‐instar larvae of field populations ranged from 0.279 to 6.14 and 0.589 to 14.0 mg spinosad litre⁻¹, respectively. A Thailand population was 22‐ and 24‐fold less susceptible than the six other US field populations evaluated, and 85‐ and 58‐fold less susceptible than a reference laboratory population, respectively. From these results, we initiated experiments to test the hypothesis that the Thailand population was resistant to spinosad. F₁ crosses between the resistant Thailand population and a susceptible reference strain yielded individuals that were 22‐fold less sensitive to spinosad than the susceptible parent. This same resistant strain exhibited significantly greater survivorship on plants treated with spinosad in the field. Lastly, selection of an Arizona population resulted in a significant reduction in susceptibility to spinosad, further substantiating the hypothesis of a genetic basis for resistance to spinosad. These findings indicate a vulnerability of this new insecticide to resistance development in beet armyworm and should serve as a warning against excessive use of it. © 2000 Society of Chemical Industry     

小菜蛾抗多杀菌素和敏感品系耐低温能力的比较

通过杂交筛选得到小菜蛾对多杀菌素敏感和高抗的纯合子品系，对二个品系在适温和经低温处理后的生长发育特性进行了比较，以探明其抗性是否伴有适合度的变化以及适合度变化与温度的关系。结果发现:高抗品系的卵经6℃低温处理14 d，孵化出的幼虫仅有7.7％正常化蛹，显著低于敏感品系61.4％的正常化蛹率；经6℃低温处理28 d，高抗和敏感品系的卵孵化率分别为27％和75％，二者差异显著；高抗品系的蛹经 5℃低温处理7～14 d后，蛹的 发育历期显著延长，其子代卵的存活力也显著下降。在适温25℃下，抗性和敏感品系之间多项生物学特性均无显著差异或差异很小。这些结果表明，小菜蛾对多杀菌素的抗性伴随有耐低温能力的适合度代价。     

多杀菌素对不同发育阶段甜菜夜蛾的毒力及其体内超氧化物歧化酶、过氧化氢酶和过氧化物酶的影响

对甜菜夜蛾的毒力测定结果表明,多杀菌素能显著降低其初孵幼虫的存活率、成虫的产卵量和成虫寿命。经6.25 μg/mL药液处理的卵,其初孵幼虫存活率仅为7.48％,而对照则为76.72％;取食12.50 μg/L药液的成虫,其产卵量和成虫寿命仅为取食蜂蜜水的1/6和1/2.5。随虫龄的增加,甜菜夜蛾幼虫对多杀菌素的敏感性显著降低,3龄、4龄幼虫的敏感性仅为2龄幼虫的1/9和1/16,且增效剂氧化胡椒基丁醚(PBO)与磷酸三苯酯(TPP)表皮点滴处理不表现增效作用。多杀菌素对甜菜夜蛾卵的孵化率、蛹重以及蛹的羽化率没有明显影响。亚致死剂量处理3龄幼虫后,其体内超氧化物歧化酶、过氧化氢酶和过氧化物酶等主要保护酶系的活性在处理后0~24 h与对照差异不明显,保护酶系与甜菜夜蛾对多杀菌素敏感性之间没有明显关系。     

Inheritance of resistance and cross-resistance to deltamethrin in Plutella xylostella (Lepidoptera: Plutellidae) from Pakistan

A field population of Plutella xylostella (L) from Pakistan was found to be highly resistant to deltamethrin (>500-fold) but had little or no resistance to spinosad, fipronil, indoxacarb, abamectin, Bacillus thuringiensis (Bt) var kurstaki, Bt var aizawai or Cry1Ac when compared with a susceptible laboratory population, Lab-UK. A sub-population was selected for six generations (laboratory G3-G8) with deltamethrin (delta-SEL), while a second sub-population was left unselected (UNSEL). Bioassays at G9 found that selection with deltamethrin gave resistance ratios of >230 compared with UNSEL (>6730 compared with Lab-UK). The delta-selected population showed no apparent cross-resistance to spinosad, fipronil or indoxacarb. Logit regression analysis of F1 reciprocal crosses between delta-SEL and Lab-UK indicated that resistance to deltamethrin in the delta-SEL population was inherited as an autosomal, incompletely dominant (D(LC) = 0.67) trait. A direct test of monogenic inheritance based on a back-cross of F1 progeny with delta-SEL suggested that resistance to deltamethrin was controlled by more than one factor.     

多杀菌素对甜菜夜蛾多酚氧化酶和羧酸酯酶的影响

报道了多杀菌素对甜菜夜蛾Spodopetera exigua(Hübner)多酚氧化酶(PPO)和羧酸酯酶(CarE)的影响, 多杀菌素对甜菜夜蛾表现了很高的毒力,对三龄幼虫的LC50值为0.80 mg/L。离体条件下,1.0×10-3~0.5 mg/L多杀菌素对甜菜夜蛾多酚氧化酶的抑制率超过50％,且表现为随药剂浓度的增加抑制能力增强的趋势。活体条件下,0.1~0.8 mg/L多杀菌素在处理的早期诱导虫体内多酚氧化酶的活性增加,但12 h后却显著抑制多酚氧化酶的活性。1.0×10-3~1.0 mg/L多杀菌素在离体条件下对羧酸酯酶不表现任何抑制作用,但活体条件下同样能诱导虫体内羧酸酯酶活性增强。