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。     

黄曲条跳甲室内饲养方法的改进

介绍一种饲养黄曲条跳甲Phyllotreta striolata(Fabricius)的改进新方法,采用分隔式养虫笼饲养成虫和萝卜"凹"型孔饲养幼虫,结果表明,使用该方法进行饲养,卵的成活率可达89.3%,1~3龄幼虫的存活率为65.0%~70.0%,蛹的存活率达80.0%,可以有效实现黄曲条跳甲的室内饲养。     

植物提取物对黄曲条跳甲成虫毒作用的研究

研究24种植物提取物对黄曲条跳甲成虫的毒杀活性.结果表明处理后72h,供试植物提取物中的7种对黄曲条跳甲成虫有毒作用,但毒杀活性较低,其中烟碱对黄曲条跳甲成虫的毒杀效果最好,累积死亡率为3.33%;假莲翘Duranta repens 乙醇得取物对黄曲条跳甲成虫的毒杀效果最差,累积死亡率为1.12%;其余提取物对黄曲条跳甲成虫的毒杀效果居中,累积死亡率为1.67%-2.78%.因此,毒杀作用并不是供试植物提取物对黄曲条跳甲成虫的主要控制机理.     

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.     

植物提取物对黄曲条跳甲成虫毒杀作用的研究

研究24种植物提取物对黄曲条跳甲成虫的毒杀活性。结果表明：处理后72h,供试植物提取物中的7种对黄曲条跳甲成虫有毒杀作用,但毒杀活性较低,其中烟碱对黄曲条跳甲成虫的毒杀效果最好,累积死亡率为3．33％;假莲翘Duranta repeens乙醇提取物对黄曲条跳甲成虫的毒杀效果最差,累积死亡率为1．21％;其余提取物对黄曲条跳甲成虫的毒杀效果居中,累积死亡率为1．67％-2．78％。因此,毒杀作用并不是供试植物提取物对黄曲条跳甲成虫的主要控制机理。     

马缨丹提取物对黄曲条跳甲成虫的生物活性

测定了马缨丹(Lantana camaraL.)地上部位(茎叶花)的不同溶剂提取物及萃取物对黄曲条跳甲Phyllotreta striolata(Fabricius)成虫的取食忌避、拒食、胃毒和触杀作用。结果表明:处理后48 h,以马缨丹乙醇回流提取物效果最好,其对黄曲条跳甲成虫的取食忌避率达94.94%;非选择性拒食率为85.48%;除正丁醇萃取物对黄曲条跳甲成虫的胃毒作用达到56.67%外,其它处理对黄曲条跳甲成虫的胃毒作用不明显;石油醚萃取物、石油醚冷浸物、乙醇回流物对黄曲条跳甲成虫的触杀作用效果最好,分别为56.67,53.33和53.33%。据实验结果可知马缨丹不同溶剂提取物及萃取物对黄曲条跳甲成虫的生物活性主要表现在对成虫较强的忌避和拒食作用。     

环境因素对黄曲条跳甲种群扩散的影响

应用标记回收技术,研究了寄主及气象因素对黄曲条跳甲种群扩散的影响.结果表明,黄曲条跳甲的自然扩散是由环境引起(τ≈1),温度、风速与之有一定的相关性(P<0.05),高温不利于黄曲条跳甲的扩散,其扩散主要沿逆风或与风向垂直方向进行,而湿度与黄曲条跳甲成虫扩散无显著相关(P>0.05).寄主是影响黄曲条跳甲扩散的重要因子,在几种寄主植物中,菜心上收集的标记成虫数最多,其次为芥菜,再次为白菜,芥蓝上基本没有.     

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。     

黄曲条跳甲田间种群发生的生态干扰

利用黄板诱集方法,监测黄曲条跳甲（Phyllotreta striolata）田间成虫的数量动态,发现该虫在福州全年均可发生危害,没有明显的越冬现象。2002～2003年共出现4个较为明显的成虫发生高峰和3个明显的成虫数量低谷。田间成虫数量与降雨、气温的相关分析表明,黄曲条跳甲的成虫发生与降雨、气温的关系不显著,但受到降雨、气温的复合作用。黄曲条跳甲成虫在不同寄主上的发生量存在明显的差异,数量变化在一茬菜的生长过程中也不同。黄曲条跳甲成虫对寄主具有明显的选择作用。     

黄曲条跳甲食性的研究

黄曲条跳甲 (Ｐｈｙｌｌｏｔｒｅｔａｓｔｒｉｏｌａｔａ (Ｆａｂｒｉｃｉｕｓ) )是十字花科植物的重要害虫。据文献记载 ,黄曲条跳甲除为害十字花科植物外 ,还取食茄科(Ｓｏｌａｎａｃｅａｅ)、豆科 (Ｌｅｇｕｍｉｎｏｓａｌｅｓ)、葫芦科 (Ｃｕｃｕｒ ｂｉｔａｃｅａｅ)、禾本科 (Ｇｒａｍｉｎｚｌｅｓ)等植物[1,2 ,4 ,5] 。取食范围如此之广 ,应为多食性 (ｐｏｌｙｐｈａｇｏｕｓ)昆虫。本文拟采用十字花科的近缘科及上述各科植物对黄曲条跳甲进行非选择性取食试验 ,以确定黄曲条跳甲的食性范围。1　材料和方法1.1　供试植物甘蓝 (Ｂｒａ…     

饲养黄曲条菜跳甲实验种群的一种新方法

介绍一种简便可行的饲养黄曲条菜跳甲Phyllotretastriolata(F.)的新方法———整苗大瓶罩养法。用5种植物根部饲养越冬代,黄曲条菜跳甲均可成功地完成其生活周期,未成熟期最高存活率为63.3%,成虫平均寿命最长为219.2d,平均产卵量最大为192.4粒雌。     

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。     

On a record of the striped flea beetle <Emphasis Type="Italic">Phyllotreta erysimi</Emphasis> Weise, 1900 (Coleoptera,Chrysomelidae) from Leningrad Province,Russia

The striped flea beetle Phyllotreta erysimi Weise, 1900 was found in Leningrad Province for the first time. The specimen belongs to the nominotypical subspecies, Ph. erysimi erysimi.     

一种采集水稻二化螟卵(块)的高效简便新方法

比较了二化螟Chilosuppressalis卵块的塑料袋收集法和稻株法。结果表明 ,塑料袋法和稻株法收集的卵粒总数及卵孵化率都没有显著的差异 ,均为 2 79粒卵 雌蛾和 95 %。塑料袋法收集的卵块数较稻株法的多 ,但小卵块比例较高 ( <1 0 0粒卵 卵块 )。还讨论了采用塑料袋法收集二化螟及其它昆虫卵的优点。     

Influence of temperature, photoperiod and humidity on oviposition and egg hatch of the root-feeding flea beetle Longitarsus bethae (Chrysomelidae: Alticinae), a natural enemy of the weed Lantana camara (Verbenaceae)

The root-feeding flea beetle Longitarsus bethae Savini & Escalona, was introduced into South Africa as a candidate biological control agent for the noxious and invasive weed, Lantana camara L. As part of the study to predict the beetles' survival in its new range, the influence of climatic conditions on its egg development and reproductive performance were investigated in the laboratory. The threshold temperature (T degrees) and degree-days (DD) required for egg hatch were determined after exposing the eggs to various constant temperatures (12, 17, 22, 27 and 32 degrees C) in separate growth chambers. The DD required for egg hatch was 178.6, and the temperature threshold required for egg hatch was 11.3 degrees C. Survival of eggs varied from 27 to 56% at 32 and 17 degrees C, respectively, and was optimum between 17 and 25 degrees C. Oviposition was examined under high and low relative humidity (RH) regimes while egg hatch was determined at six RH levels, each maintained in a separate controlled growth chamber set at a constant temperature (25 degrees C). Whilst RH had no influence on oviposition, eggs were highly susceptible to aridity, and continuous exposure to relative humidity below 63% for more than three days was wholly lethal at 25 degrees C. Optimum egg hatch occurred at RH between 85 and 95% for up to 12 days. The effect of day length on oviposition and subsequent egg hatch was investigated under two photoperiod regimes. Neither oviposition nor subsequent egg hatch was influenced by photoperiod. The knowledge obtained will be useful for mass rearing as well as field release programmes for L. bethae.     

Host‐specific parasitism in the Central American striped cuckoo,Tapera naevia

Coevolutionary theories of brood parasite strategy and host defense have been informed by research on egg mimicry and host recognition. However, there is no information on the strategies of New World parasitic cuckoos and their hosts. The striped cuckoo Tapera naevia is a New World cuckoo that uses multiple host species and maintains an egg color polymorphism. To investigate if color‐matching influenced rejection behavior in hosts, I conducted an egg rejection experiment on a host that lays blue‐green eggs, the rufous‐and‐white wren Thryophilus rufalbus and a host that lays white eggs, the plain wren Cantorchilus modestus. I used spectrophotometric analysis of egg color to determine the degree of egg color‐matching. I found that at the field site the striped cuckoo lays highly mimetic eggs for the rufous‐and‐white wren, in both color and brightness. The rufous‐and‐white wren was more likely to accept mimetic artificial eggs than non‐mimetic eggs. The plain wren exhibited low rejection rates for both mimetic and non‐mimetic artificial eggs. The evidence from this study indicates that the striped cuckoo lays eggs that are closely color‐matched to those of its preferred host, the rufous‐and‐white wren, and that this mimicry improves acceptance.     

Predation on Colorado Potato Beetle Eggs by Generalist Predators in Research and Commercial Potato Plantings

Field studies quantified predation on Colorado potato beetle [Leptinotarsa decemlineata(Say)] eggs and determined the relationship between predation and egg mass abundance in research and commercial potato plantings in eastern North Carolina. Predator exclusion experiments were conducted weekly in research plantings. In addition, egg mass density and predation on egg masses were monitored throughout the season in research plots and commercial potato fields. Predation was an important source of mortality for Colorado potato beetle eggs. Survivorship of eggs exposed to predators was consistently, significantly lower than survivorship of eggs protected from predation. Averaged over 2 years, the mean survivorship of eggs protected from predation was 69%, compared with 26% survivorship of eggs exposed to predation. Regression analysis failed to detect any relationship between egg mortality due to predation and egg abundance. These results imply that efforts to reduce Colorado potato beetle populations selectively will not be offset by an according decline in abundance of natural enemies and therefore should be fully compatible with naturally occurring biological control.     

Impact of Bacillus thuringiensis – insecticides on population dynamics and egg predation of the Colorado potato beetle in North Carolina potato plantings

Field studies to assess the impact of Bacillus thuringiensis var. tenebrionis (Btt)-insecticides on Colorado potato beetle populations, egg survivorship and levels of predation on egg masses were conducted in replicated field research plots during two years. Stage-specific abundance of the Colorado potato beetle and predation on egg masses were monitored in Btt-treated and untreated potato plots in both years. The Btt-treatments significantly reduced densities of large (third and fourth instar) Colorado potato beetle larvae. The densities of large larvae remained below 0.5 and 3 per plant in the Btt-treatment while peak densities of 4.5 and 21 large larvae per plant occurred in the untreated control in 1992 and 1993, respectively. Regular sampling of egg masses indicated that predation rates in Btt-treated and untreated plots did not differ significantly although, in 1993, predation rates of up to 100% were recorded, only in Btt-treated plots. In a predator exclusion study carried out in 1992, survivorship of protected eggs was consistently higher than of eggs exposed to predation. Seasonal survivorship of exposed eggs was significantly lower in the Btt-treated than in untreated plots. Btt insecticides for control of Colorado potato beetles provided direct protection of the crop and were compatible with naturally-occurring biological control of Colorado potato beetle eggs due to predation.