定虫隆与高效氯氰菊酯对小菜蛾毒力最佳配比的筛选

采用浸叶法测定了定虫隆与高效氯氰菊酯混配后对防治小菜蛾3龄幼虫的增效作用及两种药剂混配的最佳配比。结果表明,当定虫隆与高效氯氰菊酯的配比在19.20∶35.00～24.00∶0.00之间时,混配药剂表现出增效作用;而当两种药剂的比为20.64∶4.50时,增效作用最强,此时的共毒系数最高为162。     

不同小菜蛾田间种群对氯虫苯甲酰胺药剂的敏感性

采用浸叶法测定华南地区6个不同菜场小菜蛾田间种群对氯虫苯甲酰胺的药剂敏感性,结果表明:与室内敏感种群(LC50为0.03mg/kg)相比,6个地区小菜蛾田间种群对氯虫苯甲酰胺敏感性程度明显不同,其中粤北连州、粤中惠州和粤中南东升3个地方的LC50分别为0.05mg/kg、0.11mg/kg和0.13mg/kg(抗性倍数分别为1.67、3.67和4.33,均小于5,属于敏感范畴);桂中柳州和粤中南岑村的LC50分别为0.17mg/kg和0.18mg/kg(抗性倍数分别为5.67和6.00,处于5～10之间,属于低水平抗性范畴);赣南信封的LC50为0.36mg/kg,抗性倍数12处于10～40之间,属中等抗性范畴)。     

新型杀虫剂定虫隆

定虫隆是一种新的昆虫生长调节剂类杀虫剂,由日本石原产业公司发现,并与ICI-Agro汽巴-嘉基公司联合开发,现已在许多国家登记注册。定虫隆对昆虫幼虫体内几丁质合成有较强抑制作用,是一种选择性杀虫剂。对鳞翅目害虫有卓效,但对蚜虫、蝗虫等刺吸式害虫无活性,对蜜蜂等一些重要益虫安全。与传统杀虫剂无交互抗性,可用于对害虫的综合防治,是一个非常有前途的品种。一、作用方式定虫隆主要通过摄食来毒杀昆虫,高浓度时,也表现出接触毒性。定虫隆无内吸和叶部传导活性。与其他苯甲酰脲类一样,定虫隆可     

5%定虫隆与4.5%高效氯氰菊酯乳油混剂对小菜蛾的室内毒力测定

采用浸叶法在室内条件下测定5％定虫隆、4．5％高效氯氰菊酯单剂以及不同配比混剂对小菜蛾幼虫的毒力。室内毒力测定结果表明,5％定虫隆与4．5％高效氯氰菊酯4种混剂对小菜蛾均有显著的增效作用,其中混配2的增效作用最显著,其共毒系数最高为367．22。     

超临界流体萃取法测定定虫隆残留

将超临界流体萃取(Supercritical Fluid Extraction,SFE)技术与高效液相色谱分析相结合，得到了特异性杀虫剂定虫隆的残留分析方法。SFE对定虫隆的萃取务件为：压力3000PSI，温度75℃，静态萃取时间20min，动态萃取CO2流量50Ml，改性R制0．08ml／g(甲醇)，收集溶剂甲醇，萃取样品可直接用于高效液谱分析，务件为检测器：紫外二极管阵列检测器(UV254nm)，色谱柱C18键合柱，流动相甲醇／水(80：20，V／V)，流速1ml／min，柱温25℃，保留时间：18．285min。该定虫隆残留分析方法回收率为100．94％。     

定虫隆在甘蓝及土壤中的残留动态研究

定虫隆在甘蓝生长期,作叶面喷雾防治菜青虫和小菜蛾,宜施用推荐剂量30～60毫升/亩(1.5～3克有效成分/宙),最高施用剂量为80毫升/亩(4克有效成分/亩),推荐施药次数为1～2次,最多使用4次,最后一次施药距甘蓝采收间隔期为7天。     

定虫隆在棉田环境中的残留消解动态研究

定虫隆在棉花生长期作叶面喷雾防治棉铃虫和红铃虫。北方棉区:施用推荐剂量50毫升/亩(2.5克有效成分/亩),最高剂量100毫升/亩(5克有效成分/亩),最多使用6次,最后一次施药距棉花采收间隔期为20天。南方棉区:施用推荐剂量50毫升/亩,若使用5次,最后一次施药距棉花采收间隔期为5天,若使用7次,最后一次施药距棉花采收间隔期为20天。如果使用高剂量100毫升/亩,使用7次,则最后一次施药距棉花采收间隔期为20天。     

高效液相色谱法测定萝卜中定虫隆残留量

建立了快速测定萝卜中定虫隆残留方法。样品经乙腈提取,用高效液相色谱仪进行测定。实验结果表明,方法的最低检出量为1×10-9g,最低检出质量分数为0.02mg/kg,在0.1、0.5、1.0mg/kg三种添加水平下,添加回收率范围为85.16%～95.29%,变异系数范围为3.00%～7.53%。该分析方法快速、准确、灵敏,重现性好,适用于萝卜中定虫隆残留量的检测。     

甘蓝中定虫隆残留量的高效液相色谱法测定

建立了测定甘蓝中定虫隆残留量的反相高效液相色谱方法。样品经乙腈提取,通过同相萃取柱净化,用流动相溶解后,用二极管阵列（PDA）检测器在258nm处测定。在0．3-1．2mg／kg添加水平,回收率为92．4％-98．6％,相对标准偏差为2．5％-3．9％,其检出限为0．1mg／kg。     

阿维菌素与毒死蜱对小菜蛾联合毒力的生物测定

[方法]小菜蛾是十字花科蔬菜上危害最为严重的害虫之一。采用浸液法研究了阿维菌素与毒死蜱联合混配对小菜蛾的毒力作用。[结果]结果表明:2种药剂单用时阿维菌素毒力高于毒死蜱,24 h时阿维菌素和毒死蜱的LC50值分别为380.6794、2,274.0142 mg/L。24 h内两药剂混用表现为相加作用。阿维菌素与毒死蜱的比例为1∶2.22时,48、72 h后的共毒系数可高达983和998,均表现为增效作用。[结论]随着时间的延长,2种药剂混配后表现为较强的增效作用。     

硫双威,双威菊酯防治小菜蛾的药效试验

防治小菜蛾田间小区药效试验结果表明：２０％硫双威和２０％双威菊酯可湿性粉剂在小菜蛾幼虫２－３龄期进行防治，均有较好的防效。每亩用１００克２０％可湿性粉剂校正防效在６６％以上，持效期可达７０天以上，两者药效和持效优于或接近每亩６０克１０％氯氰菊酯。     

Molecular Cloning and Characterization of a P-Glycoprotein from the Diamondback Moth,Plutella xylostella (Lepidoptera: Plutellidae)

Macrocyclic lactones such as abamectin and ivermectin constitute an important class of broad-spectrum insecticides. Widespread resistance to synthetic insecticides, including abamectin and ivermectin, poses a serious threat to the management of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), a major pest of cruciferous plants worldwide. P-glycoprotein (Pgp), a member of the ABC transporter superfamily, plays a crucial role in the removal of amphiphilic xenobiotics, suggesting a mechanism for drug resistance in target organisms. In this study, PxPgp1, a putative Pgp gene from P. xylostella, was cloned and characterized. The open reading frame (ORF) of PxPgp1 consists of 3774 nucleotides, which encodes a 1257-amino acid peptide. The deduced PxPgp1 protein possesses structural characteristics of a typical Pgp, and clusters within the insect ABCB1. PxPgp1 was expressed throughout all developmental stages, and showed the highest expression level in adult males. PxPgp1 was highly expressed in midgut, malpighian tubules and testes. Elevated expression of PxPgp1 was observed in P. xylostella strains after they were exposed to the abamectin treatment. In addition, the constitutive expressions of PxPgp1 were significantly higher in laboratory-selected and field-collected resistant strains in comparison to their susceptible counterpart.     

Effects of Methoxyfenozide-Loaded Fluorescent Mesoporous Silica Nanoparticles on Plutella xylostella (L.) (Lepidoptera: Plutellidae) Mortality and Detoxification Enzyme Levels Activities

The diamond back moth, Plutella xylostella, causes severe damage at all crop stages, beside its rising resistance to all insecticides. The objective of this study was to look for a new control strategy such as application of insecticide-loaded carbon dot-embedded fluorescent mesoporous silica nanoparticles (FL-SiO₂ NPs). Two different-sized methoxyfenozide-loaded nanoparticles (Me@FL-SiO₂ NPs-70 nm, Me@FL-SiO₂ NPs-150 nm) were prepared, with loading content 15% and 16%. Methoxyfenozide was released constantly from Me@FL-SiO₂ NPs only at specific optimum pH 7.5. The release of methoxyfenozide from Me@FL-SiO₂ NPs was not observed other than this optimum pH, and therefore, we checked and controlled a single release condition to look out for the different particle sizes of insecticide-loaded NPs. This pH-responsive release pattern can find potential application in sustainable plant protection. Moreover, the lethal concentration of the LC₅₀ value was 24 mg/L for methoxyfenozide (TC), 14 mg/L for Me@FL-SiO₂ NPs-70 nm, and 15 mg/L for Me@FL-SiO₂ NPs-150 nm after 72 h exposure, respectively. After calculating the LC₅₀, the results predicted that Me@FL-SiO₂ NPs-70 nm and Me@FL-SiO₂ NPs-150 nm exhibited better insecticidal activity against P. xylostella than methoxyfenozide under the same concentrations of active ingredient applied. Moreover, the activities of detoxification enzymes of P. xylostella were suppressed by treatment with insecticide-loaded NPs, which showed that NPs could also be involved in reduction of enzymes. Furthermore, the entering of FL-SiO₂ NPs into the midgut of P. xylostella was confirmed by confocal laser scanning microscope (CLSM). For comparison, P. xylostella under treatment with water as control was also observed under CLSM. The control exhibited no fluorescent signal, while the larvae treated with FL-SiO₂ NPs showed strong fluorescence under a laser excitation wavelength of 448 nm. The reduced enzyme activities as well as higher cuticular penetration in insects indicate that the nano-based delivery system of insecticide could be potentially applied in insecticide resistance management.     

灰飞虱的饲养及其对4种药剂的敏感性测定

从飞虱是一种重要的传毒昆虫，室内研究表明，夏季和冬季饲养灰飞虱的最佳寄主分别是物稗草和小麦：采用稻茎浸渍法和点滴法进行的生测结果表明、吡虫啉、噻嗪酮、啶虫脒及氟虫腈4种药剂中，氟虫腈的毒力最高。氟虫腈是正温度效应杀虫剂。此外，对田间灰飞虱的药剂防治策略进行了讨论。     

苏·阿防治花椰菜小菜蛾的效果

比较了苏·阿、Ｂ．ｔ．和虫螨克防治花椰菜小菜蛾的效果。药后１天,２％苏·阿可湿性粉 剂１００ｇ／６６７ｍ２的防效为９８．３％,高于Ｂ．ｔ．可湿性粉剂（１６０００ＩＵ／ｍｇ）５０ｇ／６６７ｍ２９５．９％的防效, 也高于０．９ ％虫螨克乳油 ５０ｍｌ／６６７ｍ２９５．４ ％的防效。药后１周,苏·阿的防效仍达 ９４．７７％,明显 高于Ｂ．ｔ．可湿性粉剂（１６０００ＩＵ／ｍｇ）５０ｇ／６６７ｍ２和０．９％虫螨克乳油５０ｍｌ／６６７ｍ２的防效。     

Identification of olfactory cues used in host-plant finding by diamondback moth,Plutella xylostella (Lepidoptera: Plutellidae)

Olfactory attraction of female diamondback moths (Plutella xylostella) to odors of intact and homogenized host plants, as well as individual compounds characteristic of host plants, were investigated by behavioral and electrophysiological methods. Moths were attracted to odors ofBrassica juncea andB. napus seedlings in a Y-tube bioassay. Solvent fractions of homogenizedB. juncea leaves were attractive to moths whether or not isothiocyanates (IC) were present. Moths were attracted in Y-tube bioassays and to field traps baited with individual ICs. Volatiles fromB. juncea andB. napus elicited an electroantennogram (EAG) response and were attractive in the Y-tube bioassay. Allyl IC was shown to be the attractive component in homogenized plant volatiles but was found to be virtually absent from intact plant volatiles. Gas chromatographic fractionation of intact plant volatiles revealed a terpene-containing fraction to be most attractive to the moths. We were unable to isolate individual attractive compounds from this fraction. Our results suggest that certain elements of this fraction, possibly in combination, are important olfactory cues for host-plant finding by the diamondback moth with mustard oils playing an important and possibly synergistic role, particularly when plants are damaged.     

几种药剂对小菜蛾的田间药效比较

对0．3％印楝素乳油、1％甲维盐水乳剂、1．8％阿维菌素乳油、100g／L虫螨腈悬浮剂等生物药剂防治小菜蛾的田间药效进行了试验,结果表明用药后1d防效在43％～53％,药后3d防效在74％～86％,药后7d防效在79％～90％。其中1％甲维盐水乳剂药效较为理想,具有一定的速效性及良好的持效性,可推广使用。     

Impact of Botanical Pesticides Derived from Melia azedarach and Azadirachta indica Plants on the Emission of Volatiles that Attract Parasitoids of the Diamondback Moth to Cabbage Plants

Herbivorous and carnivorous arthropods use chemical information from plants during foraging. Aqueous leaf extracts from the syringa tree Melia azedarach and commercial formulations from the neem tree Azadirachta indica, Neemix 4.5^®, were investigated for their impact on the flight response of two parasitoids, Cotesia plutellae and Diadromus collaris. Cotesia plutellae was attracted only to Plutella xylostella-infested cabbage plants in a wind tunnel after an oviposition experience. Female C. plutellae did not distinguish between P. xylostella-infested cabbage plants treated with neem and control P. xylostella-infested plants. However, females preferred infested cabbage plants that had been treated with syringa extract to control infested plants. Syringa extract on filter paper did not attract C. plutellae. This suggests that an interaction between the plant and the syringa extract enhances parasitoid attraction. Diadromus collaris was not attracted to cabbage plants in a wind tunnel and did not distinguish between caterpillar-damaged and undamaged cabbage plants. Headspace analysis revealed 49 compounds in both control cabbage plants and cabbage plants that had been treated with the syringa extract. Among these are alcohols, aldehydes, ketones, esters, terpenoids, sulfides, and an isothiocyanate. Cabbage plants that had been treated with the syringa extract emitted larger quantities of volatiles, and these increased quantities were not derived from the syringa extract. Therefore, the syringa extract seemed to induce the emission of cabbage volatiles. To our knowledge, this is the first example of a plant extract inducing the emission of plant volatiles in another plant. This interesting phenomenon likely explains the preference of C. plutellae parasitoids for cabbage plants that have been treated with syringa extracts.