芥蓝田主要害虫种群生态位研究

2001年秋季在福州郊区对芥蓝田BrassicaalboglabraBailey害虫种群的生态位进行了初步研究,研究结果表明:蚜虫、粉虱和小菜蛾为秋季芥蓝田的优势种害虫,菜青虫、黄曲条跳甲和斑潜蝇为随从种害虫。这些主要害虫的生态位在时间、空间维度和时-空二维上存在明显分化,各种害虫对资源的竞争主要集中在对空间资源的竞争,即随着时间的推移,害虫间的竞争主要集中在对植株上可获得的产卵、取食和栖息的空间资源的竞争。     

虫害诱导的植株对小菜蛾取食和生长发育的影响

本文从菜田生态系统的角度出发,就黄曲条跳甲Phyllotreta striolata(Fabricius)取食诱导对小菜蛾Plutella xylostella(L.)造成的影响进行了研究。黄曲条跳甲取食诱导对小菜蛾取食的影响比较明显,一般来说,黄曲条跳甲少量或短时间的取食会刺激小菜蛾幼虫在相应叶片上的取食,反之则会抑制;而且不同的寄主,不同完整度的叶片(即是否被黄曲条跳甲取食过)上的承载能力不同,芥菜、白菜、菜心和萝卜的承载力弱于甘蓝和芥蓝,黄曲条跳甲取食过的叶片弱于未被黄曲条跳甲取食过的叶片;不同数量的黄曲条跳甲取食对小菜蛾的产卵量影响显著,对其余生物学参数影响不显著,少量的黄曲条跳甲取食会刺激小菜蛾的产卵,多数则会抑制。     

几种十字花科蔬菜害虫生态位的研究

以Levins生态位宽度指数和Pianka生态位重叠指数估计发生在同一营养阶层的 4种主要十字花科植物害虫营养生态位、时间生态位和空间生态位的生态位宽度和重叠度。结果表明小菜蛾、黄曲条跳甲、菜粉蝶和小猿叶甲 4种昆虫的生态位并不完全重叠。     

球孢白僵菌对四种十字花科蔬菜害虫的兼控潜力评价

研究了分离自小猿叶甲的一株球孢白僵菌(Beauveria bassiana(SCAU-BB01D))对十字花科蔬菜4种非目标害虫烟粉虱Bemisia tabaci、小菜蛾Plutella xylostella、黄曲条跳甲Phyllotreta striolata和菜缢管蚜Lipaphis erysimi的致病能力。结果表明,在实验室条件下,该菌株对以上4种害虫均有不同程度的侵染力。1×108孢子/mL的白僵菌悬浮液对1,2,3,4龄烟粉虱若虫的侵染率分别为84.88,86.81,55.94和38.78%;对小菜蛾2,3和4龄幼虫的侵染率为67,59和44%;对黄曲条跳甲幼虫和成虫分别为63%和60%;对菜缢管蚜成蚜和若蚜的侵染率分别为44%和35%。通过机率值分析,得出该菌株对烟粉虱1~4龄若虫的LT50分别为4.14,3.78,6.24和7.59 d;对小菜蛾2~4龄幼虫的LT50分别为7.29,8.16和9.82d;对黄曲条跳甲成虫和幼虫的LT50分别为11.22和8.11 d;对菜缢管蚜成蚜和若蚜的LT50分别为11.01和12.15 d。说明该球孢白僵菌菌株对烟粉虱、小菜蛾和黄曲条跳甲3种非目标害虫具有一定的兼控作用,在蔬菜害虫的生物防治中具一定的应用潜力。     

不同蔬菜害虫对色彩的趋性差异

试验表明,黄曲条跳甲PhyllotretastriolataF.、桃蚜Myzuspersicae(Sulzer)、和美洲斑潜蝇LiriomyzasativaeBlanchard对不同颜色的趋向性存在差异,黄曲条跳甲对黄色和白色的趋性强,桃蚜和美洲斑潜蝇对黄色最敏感,小菜蛾Plutellaxylostella(L.)成虫对绿色的敏感性明显强于其他色彩。在生产上,可利用害虫对颜色的趋性进行害虫预测预报或害虫控制。     

黄曲条跳甲种群分化的RAPD分析

采用RAPD方法,对福建省19个不同菜区黄曲条跳甲地理种群的分化进行了研究。结果表明：相同种群采用相同引物进行扩增的重复性较好,不同种群采用相同引物进行扩增的差异性较高;19个不同菜区的黄曲条跳甲主要分为4个类群：闽东南沿海地区类群、闽西北地区类群、泉州类群和东山岛类群,黄曲条跳甲不同地理种群的遗传距离与地理距离有关。东山岛和泉州2个特异性类群的出现,说明地形、蔬菜种植以及农药使用等人为因子会影响其地理种群的分化。     

黄曲条跳甲对毒死蜱敏感性差异的生化机制

采用生物测定方法测定黄曲条跳甲Phyllotreta striolata(F.)2个室内试验种群(蔊菜试验种群、上海青试验种群)和1个田间自然种群对毒死蜱的LC50值。结果表明,蔊菜试验种群对毒死蜱的LC50值最低,为30.3459mg.L-1;田间自然种群对毒死蜱的LC50值最高,为77.8448mg.L-1,与蔊菜试验种群相比的敏感性指数为0.39。对不同种群黄曲条跳甲乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)、谷胱甘肽-S-转移酶(GSTs)的活性测定结果表明,黄曲条跳甲田间自然种群AChE活性最低,与菜试验种群、上海青试验种群相比,差异极显著(P>0.01);田间自然种群GSTs活性最高,与蔊菜试验种群、上海青试验种群相比,差异极显著(P>0.01);黄曲条跳甲蔊菜试验种群CarE活性最低,田间自然种群CarE活性最高,二者差异极显著(P>0.01);说明黄曲条跳甲对毒死蜱的敏感性下降可能与AChE活性的降低,与CarE、GSTs的活性提高有一定的关系。     

黄曲条跳甲人工饲养技术改进

通过室内人工饲养建立实验种群,是开展黄曲条跳甲Phyllotreta striolata(Fabricius)各种研究的基础,解决其幼虫阶段的人工饲养技术是建立其实验种群的关键。介绍经改进后的黄曲条跳甲室内人工饲养技术,该方法简单易行,可以方便地获取试虫的不同虫态;采用"小菜苗法"和"萝卜薄片堆叠法"室内饲养黄曲条跳甲幼虫,最高存活率可达90%以上。     

黄曲条菜跳甲幼虫龄数的划分

<正> 黄曲条菜跳甲 Phyllotreta striolata(Faricius)是十字花科蔬菜的重要害虫之一,成虫取食植物叶片,幼虫生活在土壤里,为害植物根部。在过去的报道中,对其幼虫的龄数划分     

苏云金芽胞杆菌HA和HD对黄曲条跳甲成虫的毒力分析

黄曲条跳甲Phyllotreta striolata (Fabricius)是为害十字花科蔬菜的世界性害虫之一.为了探究苏云金芽胞杆菌HA和HD对黄曲条跳甲成虫的防治潜力,本研究测定了苏云金芽胞杆菌HA和HD菌株对黄曲条跳甲成虫的毒力,以及对其谷胱甘肽-S-转移酶(GST)活性和中肠组织形态的影响.结果 表明:Bt-HA和Bt-HD均对黄曲条跳甲成虫有杀虫活性,LC50分别为4.01×108 CFU/mL和1.17×108 CFU/mL.菌株Bt-HD处理组的GST酶活性高于对照组和菌株Bt-HA处理组.菌株Bt-HA处理黄曲条跳甲成虫14 d后,中肠微绒毛肿胀脱落;菌株Bt-HD处理黄曲条跳甲成虫4d后中肠微绒毛开始疏松脱落,14 d后中肠柱状细胞底膜变形脱落.综上所述,苏云金芽胞杆菌HD对黄曲条跳甲成虫的毒力更强,是防治黄曲条跳甲成虫的优势菌株,其杀虫机理值得深入研究.     

TWO HERBIVORES AND CONSTRAINTS ON SELECTION FOR RESISTANCE IN BRASSICA RAPA

Although most plants experience herbivory by several insect species, there has been little empirical work directed toward understanding plant responses to these simultaneous selection pressures. In an experiment in which herbivory by flea beetles (Phyllotreta cruciferae) and diamondback moths (Plutella xylostella) was manipulated in a factorial design, I found that selection for resistance to these herbivores is not independent in Brassica rapa. Specifically, the effect of flea beetle damage on B. rapa fitness depends on the amount of diamondback moth damage a plant experiences: damage by these herbivores has a nonadditive effect on plant fitness. When diamondbacks are abundant, plants that sustain high levels of damage by flea beetles are favored by natural selection, but when diamondbacks are rare, a low level of damage by flea beetles is favored. However, resistance to the later-feeding diamondback moth is not affected by the presence or absence of damage by early-feeding flea beetles. Thus, there are no plant-mediated ecological interactions between these herbivores that affect the outcome of selection for resistance. Because these herbivores do not independently affect plant fitness, neither is likely to develop a pairwise coevolutionary relationship with its host. Instead, coevolution is diffuse.     

Cyt1A from Bacillus thuringiensis lacks toxicity to susceptible and resistant larvae of diamondback moth (Plutella xylostella) and pink bollworm (Pectinophora gossypiella)

We tested Cyt1Aa, a cytolytic endotoxin of Bacillus thuringiensis, against susceptible and Cry1A-resistant larvae of two lepidopteran pests, diamondback moth (Plutella xylostella) and pink bollworm (Pectinophora gossypiella). Unlike previous results obtained with mosquito and beetle larvae, Cyt1Aa alone or in combination with Cry toxins was not highly toxic to the lepidopteran larvae that we examined.     

Invertebrate pests of canola and their management in Australia: a review

Abstract  In Australia, canola is subject to attack by at least 30 species of invertebrate pests, although the composition of this pest complex can vary between regions. Mites (e.g. the redlegged earth mite Halotydeus destructor and the blue oat mites Penthaleus spp.), lucerne flea ( Sminthurus viridis ) and false wireworms (e.g. the grey false wireworm Isopteron punctatissimus and the bronzed field beetle Adelium brevicorne ) are the major pests threatening the seedling establishment, whereas aphids (the cabbage aphid Brevicoryne brassicae , the turnip aphid Lipaphis erysimi and the green peach aphid Myzus persicae ), the native budworm ( Helicoverpa punctigera ), the diamondback moth ( Plutella xylostella ) and the Rutherglen bug ( Nysius vinitor ) can cause irregular and unpredictable damage to the flowering and podding plants. Current tactics of pest management for canola rely largely on the use of synthetic pesticides, but this single-technology approach is likely to incur negative effects on natural enemies and the risk of pest resistance. Thus, the sustainable production of canola requires integrated pest management (IPM) strategies, in which cultural control, crop resistance and biological control are used as important components, with chemical inputs applied only when absolutely needed to restrict pests from reaching economically damaging densities. Such IPM strategies should be built around a fundamental understanding of pest ecology at both regional and local farm levels and the integration of renewable technologies. Therefore, future research efforts need to be focused on the canola-cropping system, with a particular emphasis on the impact of pest species, natural enemies of the pests, varietal resistance to pests and the spatial ecology of pest species.     

Greenhouse and field evaluations of transgenic canola against diamondback moth, shape Plutella xylostella, and corn earworm, shape Helicoverpa zea

Canola (Brassica napus L.) cultivars Oscar and Westar, engineered with a Bacillus thuringiensis (Bt) cryIA(c) gene, were evaluated for resistance to lepidopterous pests, diamondback moth, Plutella xylostella L. (Plutellidae) and corn earworm, Helicoverpa zea (Boddie) (Noctuidae) in greenhouse and field conditions. In greenhouse preference assays conducted at vegetative and flowering plant stages, transgenic plants recorded very low levels of damage. A 100% diamondback moth mortality and 90% corn earworm mortality were obtained on transgenic plants in greenhouse antibiosis assays. The surviving corn earworm larvae on transgenic plants had reduced head capsule width and body weight. Mortality of diamondback moth and corn earworm were 100% and 95%, respectively, at different growth stages (seedling, vegetative, bolting, and flowering) on the transgenic plants in greenhouse tests. In field tests conducted during 1995–1997, plots were artificially infested with neonates of diamondback moth or corn earworm or left for natural infestation. Transgenic plants in all the treatments were highly resistant to diamondback moth and corn earworm larvae and had very low levels of defoliation. Plots infested with diamondback moth larvae had greater damage in both seasons as compared with corn earworm infested plots and plots under natural infestation. After exposure to defoliators, transgenic plants usually had higher final plant stand and produced more pods and seeds than non-transgenic plants. Diamondback moth injury caused the most pronounced difference in plant stand and pod and seed number between transgenic and non-transgenic plants. Our results suggest that transgenic canola could be used for effective management of diamondback moth and corn earworm on canola.     

Cyt1A from Bacillus thuringiensis Lacks Toxicity to Susceptible and Resistant Larvae of Diamondback Moth (Plutella xylostella) and Pink Bollworm (Pectinophora gossypiella)

We tested Cyt1Aa, a cytolytic endotoxin of Bacillus thuringiensis, against susceptible and Cry1A-resistant larvae of two lepidopteran pests, diamondback moth (Plutella xylostella) and pink bollworm (Pectinophora gossypiella). Unlike previous results obtained with mosquito and beetle larvae, Cyt1Aa alone or in combination with Cry toxins was not highly toxic to the lepidopteran larvae that we examined.     

Novel chlorantraniliprole derivatives as potential insecticides and probe to chlorantraniliprole binding site on ryanodine receptor

The lepidopteran pests such as diamondback moth are the regularly harmful pests of crops in the world, which brings enormous losses in crop production. Chlorantraniliprole is an anthranilic diamide insecticide registered for the control of lepidopteran pests with high insecticidal activity, however with uncertain binding site action target of chlorantraniliprole on ryanodine receptor, a series of new chlorantraniliprole derivatives were synthesized and the insecticidal activities of these compounds against diamondback moth were evaluated with chlorantraniliprole and indoxacarb as control. All compounds except 8h, 8p and 8t exhibited varying degree of activities against diamondback moth. Especially, compounds 8c, 8i, 8k and 8l displayed good insecticidal activities against diamondback moth and the activities are even better than that of indoxacarb during 72 h period. The K_i values of all synthesized compounds were calculated through autodocking program respectively. The relationship between calculation value of molecular docking and results of insecticidal activities indicated that the proposed specific receptor, the membrane-spanning domain protein of diamondback moth ryanodine receptor in our study might have chlorantraniliprole binding sites.     

Efficacy of Piper (Piperaceae) extracts for control of common home and garden insect pests

Extracts from three species of the plant family Piperaceae, Piper nigrum [L.], Piper guineense [Schum & Thonn, and Piper tuberculatum [Jacq.], were tested for efficacy against insects from five orders. All three species contain isobutyl amides, plant secondary compounds that act as neurotoxins in insects. These materials are considered safe to mammals because Piper spp. were used for centuries for spice and medicinal purposes. When 24-h P. nigrum LC50 values were compared between common insect pests from eastern Canada and the northeastern United States, the most sensitive species in order of increasing lethal concentration were eastern tent caterpillar, Malacosoma americanum (F.) < European pine sawfly larvae, Neodiprion sertifer (Geoffroy) < spindle ermine moth larvae, Yponomeuta cagnagella [Hübner] < viburnum leaf beetle larvae, Pyrrhalta viburni [Paykull] < stripped cucumber beetle adults, Acalymma vittatum (F.) < Colorado potato beetle adults, Leptinotarsa decemlineata (Say) < Japanese beetle adults, Popillia japonica [Newman] < hairy chinch bug, Blissus leucopterus hirtis [Montandon]. The life stage tested was the point at which each species causes the greatest amount of damage to the host plant and the point at which most gardeners would likely choose to treat with a conventional synthetic insecticide. Greenhouse trials revealed that the pepper formulations also had a repellent activity, thus protecting plant leaves from 1) herbivory (lily leaf beetle, Lilioceris lilii [Scopoli], adults and larvae and stripped cucumber beetle adults) and 2) oviposition [European corn borer, Ostrinia nubilalis (Hübner)]. Combinations with other botanical extracts were additive at best in toxicity and repellent trials. Nontarget toxicity to beneficial invertebrates is a possibility because the P. nigrum LC50 for beneficial ladybird beetles was 0.2%. P. nigrum extracts can provide a reasonable level of control against lepidopteran and European pine sawfly larvae and also will work as a short-term repellent and feeding deterrent. It is recommended that the use of Piper extracts be restricted to small-scale spot treatments in residential areas where insect pest outbreaks have occurred.