芫花乙醇粗提物对菜粉蝶幼虫消化酶系的影响

菜粉蝶（Ｐｉｅｒｉｓ ｒａｐａｅ）幼虫取食芫花粗提物２４ｈ后,中肠淀粉酶、蛋白酶、酯酶、转化酶的活力增强,其中肠组织中淀粉酶及肠腔中蛋白酶活力增强的程度达显著水平;粗提物使海藻糖酶活力下降,差异达显著水平。石蜡切片表明,芫花引起细胞核向肠腔内侧移动,围食膜逐渐消失,肠壁细胞中的空泡显著增多、增大,肠组织结构变得没有层次性。电镜观察表明,芫花粗提物处理２４ｈ后,引起细胞内粗糙内质网上的核糖体数量明显增多,线粒体内嵴开始模糊、肿胀。因而认为,粗提物刺激组织超量分泌消化酶,加之抑食作用使取食量减少,导致体重减轻,体能逐渐衰竭而死亡。     

二株莱氏野村菌对斜纹贪夜蛾幼虫的致病性(英文)

二株莱氏野村菌分别分离自日本的淡剑贪夜蛾和大豆夜蛾 ,将他们接种于斜纹贪夜蛾的幼虫 ,并饲以人工饲料 .共设置 5个分生孢子悬浮液的浓度梯度 ,即 10 7,10 6 ,10 5,10 4 ,10 3孢子 /毫升 .对斜纹贪夜蛾幼虫的毒力试验结果表明 :分离自淡剑贪夜蛾菌株的LC50为 5 38,分离自大豆夜蛾菌株的LC50为 5 71,10 7孢子 /毫升浓度分生孢子悬浮液的致病死亡率分别为 89 5%和 84 2 %     

斜纹夜蛾对森林苗木的危害状及防治措施初报

斜纹夜蛾是一种杂食性害虫,在森林苗圃中暴发成灾,在掌握其危害苗木规律及其生活习性的基础上,提出相应的防治措施。     

四种植物提取物对斜纹夜蛾卵的毒杀效果

以斜纹夜蛾卵为研究对象．对雷公藤Tripter gium wilfordii茎、皂荚Gleditsia sinensis Lam．刺、苦参Sophora flavescens和博落茴Macleya cordata等4种植物材料的正已烷及乙酸乙酯提取物的杀卵活性进行了测定。结果表明：博落茴的乙酸乙酯提取物对斜纹夜蛾卵有较好的杀伤力,校正未孵化率高达95．63%;雷公藤的乙酸乙酯提取物和苦参的正已烷提取物对斜纹夜蛾卵的孵化也有明显的抑制作用。     

油茶斜纹夜蛾、黄刺蛾的生活习性与防治方法

一、斜纹夜蛾 1.危害情况 危害荷花、睡莲、大丽花、木槿、月季、百合、仙客来、菊花、山茶、葛兰等约200余种.初孵幼虫取食叶肉,2龄后分散危害,4龄后进入暴食期,将整株叶片吃光,影响植物正常生长,严重时可至植株死亡.     

苦楝花粉飘散对林内空气颗粒物浓度的影响

针对城市绿化建设中气传花粉导致的植源污染,开展气传致敏花粉传播的时空变化规律及其对林内空气颗粒物浓度的影响研究,为防控城市气传致敏花粉污染提供依据。以成都市绿化使用频率较大、典型气传致敏花粉植物-苦楝为研究对象,选择苦楝的盛花期,开展气传致敏花粉的日变化飘散规律和水平空间传播规律研究,结果表明：(1)苦楝花粉浓度的日变化呈单峰曲线,即花粉浓度从6:00—14:00持续上升,并在14:00达到峰值;14:00—20:00则持续下降;12:00—15:00的花粉飘散浓度显著性高于其余时段。(2)苦楝花粉浓度的水平方向上,顺风方向花粉浓度高于逆风方向;顺风方向花粉浓度变化呈单峰曲线,随着距离的增加而增加,并在20 m处达到峰值;逆风方向花粉的飘散浓度呈双峰曲线,峰值出现在9 m和20 m。(3)受苦楝花粉飘散的影响,香樟林内空气颗粒物浓度在水平空间上的含量分布趋势与花粉浓度变化趋势大致相同,也表现为顺风方向高于逆风方向;在水平距离上,苦楝花粉对空气颗粒物的影响主要在0—30 m范围。     

橡胶树种子中水分和氰苷含量变化对两种实验鼠取食行为的影响

为了探究橡胶树种子中毒性氰苷类物质(HCN)的存在和含量变化对橡胶树种子捕食者取食行为的影响,将新鲜橡胶树种子置于室内自然放置不同天数,获得不同水分和氰苷含量的实验种子,并将其饲喂给野外半自然围栏场中的两种鼠类捕食者,观测其取食行为和格局。结果表明,黄胸鼠(Rattus flavipectus)对放置时间少于30 d、水分和氰苷含量较高的种子主要进行分散贮藏(几乎100%);对放置30 d以上、水分和氰苷含量低的种子是以分散贮藏为主(33%~100%),同时也会进行部分搬运后取食和巢内贮藏;但相关性分析表明,黄胸鼠对橡胶树种子的取食数量与放置天数或与水分及氰苷含量之间并无显著相关关系。红刺鼠(R.surifer)对放置少于30 d水分和氰苷含量较高的种子更多是采取即时取食的方式,显然未受氰苷存在的影响;而对放置30 d以上、水分和氰苷含量低的种子则主要是进行贮藏,可能是因为这样的种子更利于保存。综上所述,黄胸鼠和红刺鼠对橡胶树种子的取食行为仍是受其各自取食习性主导的,氰化物的存在和含量变化并未对其产生显著影响。该研究结果将有助于更好地理解小型啮齿类对橡胶树种子的捕食格局和传播能力,为橡胶林管理和森林保护提供某些依据。     

芫花活性物质对昆虫取食和生长的影响

室内生测表明不同浓度芫花乙醇粗提物（YAE）处理叶饲养卫矛尽Hu24h后，导致试虫食量减少，体重下降，且浓度与效果呈正相关，如10％芫花处理组食叶量比CK减少53.78％（重量计），虫重比原来下降14.81%，而K体重增加19.51%。β－谷甾醇对试虫食叶量影响虽不明显，但1.0%,0.5%,0.1%处理仍可使虫体显著下降。YAE的拒食中浓度为2.76％β－谷甾醇为0.34%。YAE及β－谷甾醇 对4龄斜纹夜蛾的抑制取食及生长的作用均不及卫矛尺Hu显著。     

肋果茶枝叶乙醇提取物对小菜蛾幼虫拒食及毒杀活性的研究

用提取物试液浸渍甘蓝圆形叶碟饲喂害虫幼虫的方法测定了肋果茶枝叶乙醇提取物对小菜蛾3龄幼虫的拒食及毒杀活性.结果表明,肋果茶枝叶乙醇提取物能使小菜蛾幼虫取食量减少,死亡率增加,羽化率降低.其提取物试液的浓度越高,这些作用的效果越明显.在非选择性的条件下,肋果茶枝叶乙醇提取物试液对小菜蛾3龄幼虫的有效拒食浓度(AFC50)24 h 时为151.88 mg/L,48 h 时为94.53 mg/L.     

马尾松抽出物对盐水虾幼体的致死活性

盐水虾（Ａｒｔｅｍｉａｓａｌｉｎａ．Ｌ）法是一种简单、易行,对多种生物学活性都有效的生物测定法。通过实验测出活性成分和抽出物在盐水培养基中的中央致死浓度ＬＣ５０（μｇ／ｍｌ）,结果表明马尾松抽出物对盐水虾幼体具致死活性。     

Antifeedant activity of Momordica dioica fruit pulp extracts on Spodoptera litura

The hexane extract and ethyl acetate soluble fraction of methanolic extract of the fruit pulp of Momordica dioica exhibited moderate and concentration dependent antifeedant activity against Spodoptera litura.     

油茶蒲提取物的抗氧化活性

以油茶蒲粗提物为原料,将其溶于水后用不同的有机溶剂分级萃取,得到乙酸乙酯相、正丁醇相及水相。应用Folin-Ciocalteau法测定粗提物及分级萃取各相的总酚含量;同时应用DPPH法、TEAC法、FRAP法和全血体系总抗氧化能力(T-AOC法),以抗坏血酸(Vc)为阳性对照分别测定粗提物及分级萃取各相的抗氧化能力。结果表明:油茶蒲提取物具有较强的抗氧化能力,应用4种方法测定的结果一致,抗氧化能力强弱为:乙酸乙酯相>正丁醇相>粗提物>水相,总酚含量与抗氧化能力间存在较好的相关性。     

Insecticidal activity of essential oils to the tobacco cutworm, Spodoptera litura

Twenty-one essential oils were tested for insecticidal activity via topical administration to third instar larvae of the tobacco cutworm, Spodoptera litura. Oils of Satureia hortensis, Thymus serpyllum and Origanum creticum produced >90% larval mortality at 24 h at a dose of 100 microg per larva. The LD(50) value for S. hortensis (48.4 microg) was comparable to that for Thymus vulgaris (46.9 microg). The monoterpenoid phenols thymol and carvacrol, major constituents of the oils of Thymus and Satureia species, likely account for the insecticidal action of the species.     

The effect of oviposition experience of adult Microplitis pallidipes parasitoids on discrimination between nucleopolyhedrovirus-infected and healthy Spodoptera litura larvae

Using multiple pest-mortality sources is a basic tenet of IPM, but they may not always be compatible. To that end, we examined compatibility of parasitism and nucleopolyhedrovirus (NPV) infected. Specifically, we examined the effects of prior oviposition experience by Microplitis pallidipes on its ability to distinguish NPV-infected from healthy larvae of Spodoptera litura. We found that time spent searching for hosts was significantly lower, while the number of attacks, percentage of first attacks, and parasitism rate were all significantly higher in healthy versus virus-infected hosts for parasitoids that had experienced healthy hosts. Meanwhile, parasitoids that had experienced infected hosts spent significantly more time searching for infected hosts starting on day 2. For these parasitoids, the number of attacks, percentage of first attacks, and parasitism rate were all significantly lower from day 2 in virus-infected versus healthy larvae. We found no significant differences between parasitoids without experience versus ones experienced with infected hosts in search time for infected hosts, number of infected host attacks, or percentage of first attacks on infected hosts. In comparison, parasitoids that had experienced healthy hosts spent less time searching for healthy hosts than parasitoids without experience, and displayed a higher frequency of attack on healthy hosts and a higher percentage of first attacks on healthy hosts. Experience with healthy larvae aided parasitoids in distinguishing healthy from virus-infected larvae, but experience with virus-infected larvae did not convey the same discrimination. This information provides a better understanding of how to integrate NPV applications with naturally occurring parasitism for this pest in crops.     

竹提取物对棉铃虫幼虫体内几种酶系活性的影响

植物源农药的研究与开发是当前农药学领域较为活跃的研究方向,一方面从植物中探寻新的活性先导化合物,通过类推合成进行新农药的开发;另一方面通过植物杀虫作用方式的研究,探寻新的杀虫作用靶标,通过生物合理设计开发新型环境友好农药(操海群等,2000).研究植物提取物及其有效成分对昆虫体内代谢酶系活性的影响,探讨其杀虫作用机理,对于合理利用与开发新型植物源农药具有重要意义.     

苦豆草生物碱对柳蓝叶甲的拒食作用

研究苦豆草生物碱对柳蓝叶甲取食的影响.结果表明:苦豆草生物碱总碱及其单体对柳蓝叶甲具有较强的拒食作用,且随着浓度的升高拒食作用增强.在选择性取食条件下,随着总碱处理浓度的升高,试虫对处理叶的取食量迅速下降;而对未处理叶的取食量没有显著的差异,但随着处理浓度的升高,总取食量明显下降.在供试的6种生物碱单体中,苦豆碱和槐胺碱对柳蓝叶甲的拒食活性较强.其中处理浓度为5 mg·mL-1时,在选择性取食条件下,苦豆碱的拒食率高达99.4%,而在非选择性取食条件下,则以槐胺碱的拒食活性较强,达91.7%.