小菜蛾合成性信息素田间诱蛾活性

本文介绍了应用小菜蛾Plutclla xylostella合成性信息素,顺-11-十六碳烯醛和顺-11-十六碳烯乙酸酯以及增效成份顺-11-十六碳烯醇的天然橡胶诱芯,于1982年和1983年在北京郊区和苏州郊区进行田间诱蛾试验。顺-11-十六碳烯醛和顺-11-十六碳烯乙酸酯的比例为5:5,另加入10％的顺-11-十六碳烯醇制成50微克的诱芯,诱蛾效果最高,超过5头活雌蛾。按以上成份比例和载置,含有1％或5％的反式异构体时,诱蛾效果低于纯顺式异构体,但仍有很强的诱蛾话性。当反式异构体含量为1.5％时,诱蛾效果相当于3头活雌蛾。用以上3种成份,纯顺式或含有1.5％反式异构体,制成的诱芯在北京郊区和苏州郊区于春季或秋季均可测出蛾高峰,可有效地用于虫情测报。     

合成性信息素对柑桔潜叶蛾的田间引诱作用

目前柑桔潜叶蛾的防治主要依赖化学农药, 而且生产中缺少有效测报技术。为此, 我们于2009年6月30日至10月6日在浙江宁波通过有机合成柑桔潜叶蛾Phyllocnistis citrella（鳞翅目, 细蛾科）的3种性信息素化合物顺7, 顺11, 反13-十六碳三烯醛、顺7, 顺11-十六碳二烯醛和顺7-十六碳烯醛, 配制成不同浓度比例的混合物, 进行田间试验比较其引诱活性。结果表明, 单一的顺7, 顺11, 反13-十六碳三烯醛对柑桔潜叶蛾雄蛾就可以显示较强的引诱作用, 而顺7, 顺11-十六碳二烯醛单一成分没有引诱活性, 顺7, 顺11, 反13-十六碳三烯醛与顺7, 顺11-十六碳二烯醛的二元混合物30∶1~3∶1之间活性较强, 而在30∶1的质量比例时诱虫量最高。含顺7-十六碳烯醛的三元混合物, 当顺7, 顺11, 反13-十六碳三烯醛∶顺7, 顺11-十六碳二烯醛∶顺7-十六碳烯醛三者比例为100∶10∶3时有显著增效作用。剂量与诱捕活性试验显示每枚诱芯1 mg顺7, 顺11, 反13-十六碳三烯醛的剂量引诱作用最强, 随浓度降低, 引诱作用下降。诱捕器在0.8~1.5 m之间的不同悬挂高度对诱捕数量无显著影响。结果说明, 顺7, 顺11, 反13-十六碳三烯醛、顺7, 顺11-十六碳二烯醛和顺7-十六碳烯醛组成的三元混合物诱芯可以作为柑桔潜叶蛾的诱杀技术并应用于其生物防治和预测测报。     

珠江三角洲小菜蛾区域性引诱剂的研制及诱集效应研究

小菜蛾Plutella xylostella L.是为害十字花科蔬菜的世界性大害虫。小菜蛾的综合防治技术中,昆虫信息素技术因其安全无污染的特点受到人们的关注,但由于市售性诱剂在不同蔬菜种植区的诱蛾效果存在明显差异,严重制约了该技术的推广和应用。因此,本研究开展珠江三角洲区域针对性小菜蛾引诱剂研制及田间诱集效应的研究。研究结果表明,小菜蛾合成性信息素组分顺-11-十六碳烯醛(Z11-16:Ald),顺-11-十六碳烯乙酸酯(Z11-16:Ac)与顺-11-十六碳烯醇(Z11-16:OH)均能引起小菜蛾雄成虫触角产生电生理反应。田间诱集效应试验表明,小菜蛾合成性信息素组分Z11-16:Ald,Z11-16:Ac和Z11-16:OH在诱芯中比例为30∶70∶0.1,剂量为100.1μg时的田间诱蛾效果最好,与已报道性诱剂配方50∶50以及70∶30∶1相比较,诱蛾效果增加了28%-38.1%和65.1%-66.9%,明显提高了小菜蛾引诱剂的田间诱蛾效果。适用于珠三角地区的区域性小菜蛾引诱剂的研制与应用,有望在小菜蛾地区针对性害虫生态调控技术中发挥重要作用。     

棉铃虫性外激素成分的化学分析和田间试验

利用毛细柱的气相色谱和质谱对棉铃虫（鳞翅目：夜蛾科）雌蛾腺体提取物的分析,鉴定出了他和十六碳醛、顺－9－十六碳烯醛、顺－11－十六碳烯醛、饱和十六碳醇和顺－11－十六碳烯醇,其相对比例为6．1：4．5：100：3．5：8．8。在山东、山西省的田间试验中,2mg的顺－11－十六碳烯醛和顺－9－十六碳烯醛（97：3）置橡胶塞上能有效地引诱棉铃虫雄蛾。增加4％－7％他和十六碳醛到二元混合物中诱蛾量超过二元混合物。增加1％顺－11－十六碳烯醇到二元或三元混合物中减少诱蛾量,当增加5％顺－11－十六碳醇时诱蛾量大量减少。     

不同配方信息素诱芯对二化螟的诱捕效果比较研究

2004年和2005年夏季在江淮稻区二化螟Chilo suppressalis性诱剂诱捕的结果表明：一种新型诱芯（其中顺-11-十六碳烯醛∶顺-9-十六碳烯醛为2∶1）对第1代二化螟的日平均诱捕量相当于二化螟标准诱芯的5倍左右,而在越冬代和第2代成虫发生期则分别相当于后者的1.5839倍和1.7474倍。二化螟诱捕量取决于顺-11-十六碳烯醛和顺-9-十六碳烯醛的比例,而与其各自的剂量或信息素总剂量无明显关系,且它们的最佳配比可能因世代夜间温度的不同而不同,二化螟标准诱芯在第1代诱捕效果下降的原因可能是两种不饱和十六醛比例不适。     

烟青虫(Helicoverpa assulta Guenée)信息素的结构鉴定及田间试验(英语)

北京地区的烟青虫(Helicover Pa asslta Cucn(?)e)的性信息素腺体提取物经毛细管柱气相色谱分析及GC MS分析,鉴定了6种组分.这6种组分为:十六醛(16:Ald)、顺 9—十六烯醛(Z9—16:Ald)、顺11—十六烯醛(Zll 16:Ald)、顺9—十六烯醇(Z9-16:OH)、顺11—十六烯醇(Zll-16:OH)、顺9—十六烯基乙酸酯(Z9 16:OAc),比例为10.9:58.7:3.9:14.7:1.1:10.7.田间试验表明,只有16:Ald、Z9 16:Ald和Zll 16:Ald(比例为15.3:79.2:5.5)组成的三组分诱芯和Z9—16:Ald和Zll—16:Ald(比例为93.4:6.6)组成的两组分诱芯对于雄蛾有强烈的引诱活性.在3种醛为组分的诱芯中加入Z9 16:OH明显地降低引诱活性.     

植物气味化合物与斜纹夜蛾性信息素的协同作用

为提高现有性信息素对雄蛾的引诱活性, 本研究通过大量的田间试验探索植物气味化合物与斜纹夜蛾Spodoptera litura性信息素（顺9, 反11-十四碳二烯乙酸酯∶顺9, 反12-十四碳二烯乙酸酯=10∶1）的协同作用机制。从斜纹夜蛾寄主植物和花的气味化合物中, 选择9种有代表性的化合物, 并以一定剂量分别加入到斜纹夜蛾性信息素诱芯中, 在田间测试对雄蛾的引诱活性。结果表明: 在测试的9种植源性化合物中, 发现一定剂量(每个诱芯加入0.4 mg)的苯乙醛(PAA), 具有显著提高斜纹夜蛾性信息素的引诱作用, 而高剂量的苯乙醛则强烈抑制性信息素的引诱活性; 此外, 其他各种浓度的测试化合物或混合物对性信息素则没有统计上显著的增效作用。不同剂量的苯乙醛单个化合物及各种植物气味化合物组成的混合物对斜纹夜蛾也有微弱的引诱作用。苯乙醛必须要与性信息素的完整组分(以10∶1比例混合的顺9, 反11-十四碳二烯乙酸酯和顺9反, 12-十四碳二烯乙酸酯)混合才能起作用, 缺少顺9, 反12-十四碳二烯乙酸酯则没有引诱活性。本研究证明, 苯乙醛作为理想的性信息素诱芯增效剂, 可应用于建立更理想的斜纹夜蛾性信息素诱杀技术, 对性诱害虫防治和测报具有应用价值。     

中国印度谷螟性信息素次级组份的研究

印度谷螟是我国危害性较严重的仓储害虫之一,食性很广,几乎危害每一种植物性仓储物.印度谷螟雌虫性信息素主要成份顺9,反12-十四碳二烯醇醋酸酯(TDA)早已被鉴定,并利用TDA单一组份诱捕印度谷螟雄蛾也较为有效,但该虫的完整信息素系统尚不清楚.本研究采用单个雌蛾性信息素腺体抽提技术,利用毛细管气相色谱GC保留时间定性方法和气质联用GC-MS分析鉴定技术,从印度谷螟雌虫腺体提取物中鉴定了顺9,反12-十四碳二烯醇醋酸酯(A),顺9,反12-十四碳二烯醇(B),顺9,反12-十四碳二烯醛(C)和顺9-十四碳醋酸醋(D)4种主要信息素成份,其比例为A∶B∶C∶D=100∶22∶12∶9.风洞试验结果表明,以该4种主要成分按A∶B∶C∶D=8∶2∶1∶0.8比例配制成的诱芯,其引诱雄蛾的活性接近于雌蛾腺体提取物.     

小地老虎中国种群性信息素的成分鉴定及田间试验（英文）

研究了小地老虎中国种群的性信息素组分,3日龄处女蛾单腺体性信息素提取物中性信息素的含量非常低。GC和GC-MS分析表明,小地老虎性信息素含有5种成分：顺-7-12碳乙酸酯（A）、顺-9-14碳乙酸酯（B）、顺-11-16碳乙酸酯（C）、顺-5-10碳乙酸酯（D）和顺-8-12碳乙酸酯（E）。它们的含量分别为：（0.245±0.098）、（0.080±0.031）、（0.089±0.03）、(0.085±0.031)和 (0.105±0.065)ng, 这5种物质的百分比分别为40.451±13.66、13.176±5.279、14.943±5.142、14.392±6.10和17.225±9.792,前3种物质的百分比为58.75±9.429、18.91±7.539和22.34±7.209。田间试验表明,性信息素单一组分均未诱到雄蛾,AB以3∶1的比例配成的诱芯对雄蛾有一定的引诱活性,一个诱捕器平均诱捕到2.6头。ABC组分以3∶1∶1的比例配成的诱芯对雄蛾引诱活性显著增强,一个诱捕器平均诱捕量为7.40头,是AB（3∶1）诱芯的2.8倍。诱芯中性信息素的含量对诱蛾活性有明显的影响,在剂量为200 µg时的平均诱捕量最高。     

稻纵卷叶螟性信息素在其种群监测上的应用

为探索性信息素在稻纵卷叶螟Cnaphalocrocis medinalis（鳞翅目: 螟蛾科）预测预报上的应用技术, 2009年8月15日-9月20日在浙江省海宁市, 对不同性信息素化合物配制诱芯的田间诱捕效果, 以及性信息素群集诱捕、灯光诱捕和赶蛾3种不同方法监测成虫消长规律等进行研究。结果表明: 在浙江地区以顺11-十八碳烯醛、顺13-十八碳烯醛、顺11-十八碳烯醇和顺13-十八碳烯醇以60 μg∶500 μg∶60 μg∶120 μg配制的PVC毛细管诱芯对稻纵卷叶螟的诱集效果最佳。通过性信息素诱捕、灯光诱捕和赶蛾3种方法的比较试验, 初步结果显示性诱测报可取代传统的系统赶蛾法用于稻纵卷叶螟的预测预报。     

Oviposition preferences of herbivores are affected by tritrophic interaction webs

Two tritrophic systems were experimentally coupled in the present study. One system consisted of a cabbage plant ( Brassica oleracea ), diamondback moth larvae ( Plutella xylostella ) and their parasitic wasp ( Cotesia plutellae ). The other system consisted of a cabbage plant, cabbage butterfly ( Pieris rapae ) larvae and their parasitic wasp ( Cotesia glomerata ). First, we demonstrated that parasitism by C. glomerata and C. plutellae increased and decreased, respectively, on plants infested by both herbivore species than on plants infested by their host larvae alone. We then demonstrated that adult Pl. xylostella oviposited preferentially on plants infested with Pi. rapae , whereas adult Pi. rapae revealed no significant preferences between uninfested plants or plants infested with Pl. xylostella . Based on the present results and those of our previous study, we discuss the oviposition preferences of herbivores in tritrophic contexts.     

Comparative effects of deltamethrin and Neem kernel solution treatments on Diamondback moth and Cotesia plutellae (Hym., Braconidae) parasitoid populations in the Cotonou peri-urban area in Benin

A comparison between deltamethrin and Neem kernel solution treatments on Plutella xylostella (L.) populations was made in the Cotonou peri-urban area. Diamondback moth populations were 10 times larger in deltamethrin plots, than in Neem plots after treatment. The number of marketable cabbages from Neem-treated plots was 1.5 times greater than the number from deltamethrin-treated plots. There was no apparent effect of either treatments on Cotesia plutellae (Kurdjumov) populations, the only parasitoid of the pest that was present in the area.     

The role of volatiles from cruciferous plants and pre-flight experience in the foraging behaviour of the specialist parasitoid Cotesia plutellae

The braconid Cotesia plutellae is an important larval parasitoid of the diamondback moth (Plutella xylostella), a major pest of crucifers in the tropics and sub-tropics. The in-flight searching behaviour of C. plutellae was investigated in a wind tunnel and the close-range attack behaviour observed in cages. The relative importance of volatile stimuli emanating from the plant-host-complex, oilseed rape (Brassica napus) – P. xylostella, in the long-range attraction of C. plutellae was investigated. Plants that were mechanically damaged, or damaged by P. xylostella larvae, were attractive to the parasitoid. Host-damaged leaves remained attractive to the parasitoid after removal of the host larvae. These results indicate that C. plutellae predominantly uses plant derived stimuli in its in-flight searching behaviour. An oviposition experience or contact with a host-damaged leaf prior to the bioassay significantly increased the response to these volatile cues. The foraging behaviour of C. plutellae is compared with other braconid larval parasitoids attacking lepidopteran hosts on crucifers.     

Emission of Plutella xylostella-induced compounds from cabbages grown at elevated CO2 and orientation behavior of the natural enemies

Several plant species defend themselves indirectly from herbivores by producing herbivore-induced volatile compounds that attract the natural enemies of herbivores. Here we tested the effects of elevated atmospheric CO(2) (720 micromol mol(-1)) concentration on this indirect defense, physiological properties, and constitutive and induced emissions of white cabbage (Brassica oleracea ssp. capitata, cvs Lennox and Rinda). We monitored the orientation behavior of the generalist predator Podisus maculiventris (Heteroptera: Pentatomidae) and the specialist parasitoid Cotesia plutellae (Hymenoptera: Braconidae) to plants damaged by Plutella xylostella (Lepidoptera: Plutellidae) in the Y-tube olfactometer. Elevated CO(2) levels did not affect stomatal densities but reduced specific leaf area and increased leaf thickness in cv Lennox. In addition to enhanced constitutive monoterpene emission, P. xylostella-damaged cabbages emitted homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene, sesquiterpene (E,E)-alpha-farnesene, and (Z)-3-hexenyl acetate. Growth at elevated CO(2) had no significant effect on the emissions expressed per leaf area, while minor reduction in the emission of homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-alpha-farnesene was observed at elevated CO(2) in one of two experiments. The generalist predator P. maculiventris discriminated only between the odors of intact and P. xylostella-damaged cv Rinda plants grown at ambient CO(2) concentration, preferring the odor of the damaged plants. The specialist parasitoid C. plutellae preferred the odor of damaged plants of both cultivars grown at ambient CO(2) but did not detect damaged cv Lennox plants grown at elevated CO(2). The results suggest that elevated atmospheric CO(2) concentration could weaken the plant response induced by insect herbivore feeding and thereby lead to a disturbance of signaling to the third trophic level.     

Conflicts between a fungal entomopathogen, Zoophthora radicans, and two larval parasitoids of the diamondback moth

Zoophthora radicans (Zygomycetes: Entomophthorales), Diadegma semiclausum (Hymenoptera: Ichneumonidae), and Cotesia plutellae (Hymenoptera: Braconidae) are all natural enemies of the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae). Adult C. plutellae are not susceptible to Z. radicans infection but the pathogen can infect and kill adult D. semiclausum. Infection of adult D. semiclausum prior to exposure to P. xylostella host larvae significantly reduced the number of parasitoid cocoons subsequently developing from the host larvae. Although Z. radicans infection of P. xylostella larvae prior to parasitism by D. semiclausum or C. plutellae always resulted in the death of the immature parasitoids, neither species discriminated between healthy and Z. radicans-infected host larvae in an oviposition choice experiment. However, host larvae recently killed by Z. radicans were always rejected by D. semiclausum but sometimes accepted by C. plutellae. At 20 degrees C, egg to pupa development took 6.7 and 7.8 days for D. semiclausum and C. plutellae, respectively. C. plutellae parasitism significantly increased host instar duration but D. semiclausum parasitism did not. Cadavers of P. xylostella larvae parasitized 1 day prior to fungal infection showed no reduction in Z. radicans conidia yield. However, cadavers of larvae parasitized 3 days prior to fungal infection demonstrated a marked decrease in Z. radicans conidia yield. Z. radicans infection of P. xylostella larvae < or = 4 days after parasitism resulted in 100% parasitoid mortality; thereafter, the reduction in parasitoid cocoon yield decreased as the time between parasitism and initiation of fungal infection increased. The extended duration of the host larval stage induced by C. plutellae parasitism increased the availability of the parasitoid to the pathogen. Estimates of interspecific competition indicated a similar pattern for the interaction between Z. radicans and each species of parasitoid.     

Non-host plant extracts reduce oviposition of Plutella xylostella (Lepidoptera: Plutellidae) and enhance parasitism by its parasitoid Cotesia plutellae (Hymenoptera: Braconidae)

Botanical preparations, usually from non-host plants, can be used to manipulate the behaviour of insect pests and their natural enemies. In this study, the effects of extracts of Chrysanthemum morifolium, a non-host plant of the diamondback moth, Plutella xylostella (Linnaeus), on the olfactory and oviposition responses of this phytophagous insect and on levels of parasitism by its specialist parasitoid Cotesia plutellae (Kurdjumov) were examined, using Chinese cabbage Brassica campestris L. ssp. pekinensis as the test host plant. Olfactometer tests showed that volatiles of chrysanthemum extract-treated host plants were less attractive to P. xylostella females than those from untreated host plants; and in contrast, volatiles of the chrysanthemum extract-treated host plants were more attractive to females of its parasitoid C. plutellae than those from untreated host plants. Oviposition preference tests showed that P. xylostella females laid only a small proportion of their eggs on chrysanthemum extract-treated host plants, while ovipositing parasitoid females parasitized a much higher proportion of host larvae feeding on the treated host plants than on untreated host plants. These results suggest that certain non-host plant compounds, when applied onto a host plant, may render the plant less attractive to a phytophagous insect but more attractive to its parasitoids. Application of such non-host plant compounds can be explored to develop push-pull systems to reduce oviposition by a pest insect and at the same time enhance parasitism by its parasitoids in crops.     

Host physiological changes due to parasitism of a braconid wasp, Cotesia plutellae, on diamondback moth, Plutella xylostella

Braconid wasps, Cotesia plutellae (Kurdjumov), were collected from parasitized host larvae of diamondback moth, Plutella xylostella (L.) in Korea. Virus particles were found in the oviduct lumen of C. plutellae females. Multiple nucleocapsids with approximately 30-nm diameter and variable length (30-80 nm) were surrounded with a single unit membrane envelope. The parasitization of C. plutellae completely inhibited pupal metamorphosis. The parasitized larvae showed significant decrease in feeding activity and total hemolymph proteins, especially as larval storage proteins. They also showed a significant decrease in immune capacity as evidenced by reduced ability to form hemocyte nodules and reduced phenoloxidase and lysozyme activity. Here, we show that C. plutellae has an endosymbiotic virus like other reported species in Microgastrinae, and suggest that it causes host developmental arrest and immune-depression at parasitization.     

福州郊区小菜蛾天敌种类调查

1994－1999年对福州郊区小菜蛾的天敌种类进行了调查,发现寄生性天敌6种,捕食性天敌18种。并对最为常见的菜蛾绒茧蜂Cotesia plutellae与小菜蛾幼虫的田间消长动态进行了系统观察。     

Effects of Bt plants on the development and survival of the parasitoid Cotesia plutellae (Hymenoptera: Braconidae) in susceptible and Bt-resistant larvae of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

A range of crops have been transformed with delta-endotoxin genes from Bacillus thuringiensis (Bt) to produce transgenic plants with high levels of resistance to lepidopteran pests. Parasitoids are important natural enemies of lepidopteran larvae and the effects of Bt plants on these non-target insects have to be investigated to avoid unnecessary disruption of biological control. This study investigated the effects of Cry1Ac-expressing transgenic oilseed rape (Brassica napus) on the solitary braconid endoparasitoid Cotesia plutellae in small-scale laboratory experiments. C. plutellae is an important natural enemy of the diamondback moth (Plutella xylostella), the most important pest of brassica crops world-wide. Bt oilseed rape caused 100% mortality of a Bt-susceptible P. xylostella strain but no mortality of the Bt-resistant P. xylostella strain NO-QA. C. plutellae eggs laid in Bt-susceptible hosts feeding on Bt leaves hatched but premature host mortality did not allow C. plutellae larvae to complete their development. In contrast, C. plutellae developed to maturity in Bt-resistant hosts fed on Bt oilseed rape leaves and there was no effect of Bt plants on percentage parasitism, time to emergence from hosts, time to adult emergence and percentage adult emergence from cocoons. Weights of female progeny after development in Bt-resistant hosts did not differ between plant types but male progeny was significantly heavier on wildtype plants in one of two experiments. The proportion of female progeny was significantly higher on Bt plants in the first experiment with Bt-resistant hosts but this effect was not observed again when the experiment was repeated.     

Seasonal changes of methamidophos susceptibility and biochemical properties in Plutella xylostella (Lepidoptera: Yponomeutidae) and its parasitoid Cotesia plutellae (Hymenoptera: Braconidae)

Methamidophos resistance and acetylcholinesterase (AChE) insensitivity to methamidophos, dichlorvos, and carbofuran were determined in the field populations of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) and its parasitoid Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) collected from the corresponding hosts between October 1998 and December 2003 in Fuzhou and Minhou, Fijian, China. Resistance levels to methamidophos and AChE insensitivity to the three insecticides in the two species of insects were high during autumn and spring and low during summer. Resistance to methamidophos was 15.3- and 12.6-fold higher in resistant F0 parents of P. xylostella and C. plutellae than in their susceptible F11 progeny, respectively. The bimolecular rate constant (k(i)) values of AChE to methamidophos, dichlorvos, and carbofuran were 4.6-, 6.3-, and 7.7-fold higher in F11 progeny of P. xylostella, and 3.7-, 4.5-, and 3.7-fold higher in F11 progeny of C. plutellae than those in their F0 parents, respectively. Compared with susceptible F11 progeny, the resistance ratios for methamidophos were 4.2-29.8 and 3.8-13.1 in 21 field populations of P. xylostella and C. plutellae, respectively. The k(i) values of AChE to methamidophos, dichlorvos, and carbofuran were 2.0-21.6-, 3.6-9.5-, and 2.6-9.2-fold higher in F11 progeny of P. xylostella, and 1.8-7.6-, 1.9-4.6-, and 2.2-7.6-fold higher in F11 progeny of C. plutellae than those in 21 field populations, respectively. Significant correlative variations of methamidophos resistance as well as significant correlative variations of k(i) values of AChE to insecticides between the two species of insects also were found in space and time. The k(i) values of AChE to insecticides in C. plutellae were far higher than those in P. xylostella. There were no obvious differences in the Km and Vmax of AChE between F0 parents and F11 progeny of P. xylostella and C. plutellae, respectively. But carboxylesterase activity was 1.6-fold higher in F0 parents of C. plutellae than in F11 progeny, and glutathione S-transferase activity was 1.5-fold higher in F0 parents of P. xylostella than in F11 progeny. The results suggested that the AChE insensitivity to insecticides might play the most important role in methamidophos resistance in the two species of insects. From these results, a spatial and temporal correlative evolution of methamidophos resistance and insensitive AChE was found to exist between P. xylostella and C. plutellae.