苍耳不同分离物对害虫的拒食和忌避活性

为跟踪分离苍耳的活性成分,对苍耳叶和果实的甲醇提取物进行了液-液萃取分离,测试各萃取分离物对小菜蛾(Plutella xylostella)、菜青虫(Pieris rapae)和桃蚜(Myzus persicae)的拒食、忌避(或产卵忌避)活性以及对其化蛹和羽化的影响。结果显示,苍耳的乙酸乙酯分离物较之于甲醇水分离物具有更高的活性。在0.05 g/mL处理浓度下,苍耳叶乙酸乙酯分离物对菜青虫和小菜蛾幼虫选择性拒食率高达100%和44.13%,对菜青虫非选择性拒食率为94%,对小菜蛾的选择性产卵忌避率都在50%以上,对桃蚜的选择性忌避率高于70%;同时,苍耳果实乙酸乙酯分离物处理叶片后,菜青虫幼虫无一化蛹,小菜蛾高龄幼虫发育为成虫的比率仅为对照的13.80%。以上结果提示,苍耳的有效活性成分主要存在于乙酸乙酯分离相中,对菜青虫的作用效果好于小菜蛾。     

苍耳倍半萜内酯和博落回生物碱对3种蔬菜害虫的活性比较

为探讨苍耳(Xanthium sibiricum)倍半萜内酯分离物L-Ⅱ(主要成分为4β,5β-环氧苍耳素-1a,4a-内过氧化物)的活性大小,将其与博落回(Macleaya cordata)总生物碱提取物MacSC(主要成分为血根碱和白屈菜红碱)的活性进行了比较研究.结果显示,两种测试物对试虫均表现较高活性,其中,苍耳倍半萜内酯分离物L-Ⅱ对小菜蛾(Plutella xylostella)4龄幼虫的选择性拒食中浓度(AFC50)为23.6 mg/L,活性强于博落回生物碱提取物MacSC(111.8 mg/L):在测试浓度为10 mg/mL时,L-Ⅱ处理组的小菜蛾4龄幼虫仅有4.30%发育为成虫,是对照的6.12%,小菜蛾蛹的羽化率为对照的12.05%,而MacSC的影响相对较低,两值分别为对照的33.89%和56.23%:在上述测试浓度,L-Ⅱ对桄蚜(Myzus persicae)和萝卜蚜(Lipaphis erysimi)均有较强的忌避作用,24 h忌避率分别为72.03%和74.47%,而MacSC对桃蚜的忌较效果较低(55.50%),对萝卜蚜无忌避活性.说明苍耳倍半萜内酯分离物L-Ⅱ对几种试虫的拒食、忌避和生长发育抑制活性均高于博落回总生物碱提取物MacSC.     

苍耳倍半萜内酯和博落回生物碱对三种蔬菜害虫的活性比较

为探讨苍耳（Xanthium sibiricum）倍半萜内酯分离物L-Ⅱ (主要成分为4β,5β-环氧苍耳素-1α,4α-内过氧化物) 的活性大小,将其与博落回（Macleaya cordata）总生物碱提取物MacSC （主要成分为血根碱和白屈菜红碱）的活性进行了比较研究。结果显示,两种测试物对试虫均表现较高活性,其中,苍耳倍半萜内酯分离物L-Ⅱ对小菜蛾（Plutella xylostella ）4龄幼虫的选择性拒食中浓度（AFC₅₀）为23.6 mg/L,活性强于博落回生物碱提取物MacSC（111.8 mg/L）;在测试浓度为10 mg/mL时,L-Ⅱ处理组的小菜蛾4龄幼虫仅有4.30%发育为成虫,是对照的6.12%,小菜蛾蛹的羽化率为对照的12.05%,而MacSC的影响相对较低,两值分别为对照的33.89%和56.23%; 在上述测试浓度,L-Ⅱ对桃蚜 （Myzus persicae）和萝卜蚜（Lipaphis erysimi）均有较强的忌避作用,24 h忌避率分别为72.03%和74.47%,而MacSC对桃蚜的忌较效果较低（55.50%）,对萝卜蚜无忌避活性。说明苍耳倍半萜内酯分离物L-Ⅱ对几种试虫的拒食、忌避和生长发育抑制活性均高于博落回总生物碱提取物MacSC。     

绿薄荷茎和叶的乙醇提取物对小菜蛾拒食和产卵忌避活性的影响

为有效控制小菜蛾的危害,明确绿薄荷对小菜蛾的防治效果,采用95%乙醇对绿薄荷茎和叶进行索式抽提,并测定了茎和叶提取物12.5、25.0和50.0 mg/mL浓度下小菜蛾幼虫的拒食率和成虫产卵忌避活性。结果显示,绿薄荷茎和叶的乙醇提取物对小菜蛾幼虫的拒食和成虫的产卵忌避均有显著作用,提取物浓度越高,拒食率和产卵忌避率越大。当茎和叶提取物浓度为12.5 mg/mL时,小菜蛾的拒食率最低,分别为36.16%和59.81%,产卵忌避率最低,分别为46.18%和57.78%;茎和叶提取物浓度为50.0 mg/mL时,拒食率最高,分别为82.67%和87.15%,产卵忌避率最高,分别为88.29%和98.27%。茎和叶对应的拒食中浓度(AFC_(50))最高分别为18.93 mg/mL和15.97 mg/mL,产卵忌避中浓度(AOC_(50))最高分别为16.38 mg/mL和15.03 mg/mL。     

虱螨脲对小菜蛾成虫繁殖力及子代种群发展的影响

为探究虱螨脲对小菜蛾Plutella xylostella成虫的亚致死作用,通过残留药膜法或饲喂法使用50 mg/L虱螨脲对小菜蛾成虫进行处理,分别测定小菜蛾成虫繁殖力、寿命和卵孵化率,通过建立小菜蛾成虫子代生命表确定虱螨脲处理成虫对其后代的影响。结果表明,残留药膜法处理后,小菜蛾成虫单雌产卵量和卵孵化率分别比对照显著降低39.09粒和19.38个百分点;饲喂法处理后,小菜蛾成虫单雌产卵量、雌成虫寿命和卵孵化率分别比对照减少13.42粒、1.56 d和72.03个百分点,卵孵化率与对照差异显著。虱螨脲处理后,小菜蛾成虫子代1龄幼虫存活率、雌成虫寿命、F_1代单雌产卵量和F_1代卵孵化率分别为74.29%、5.90 d、146.65粒和84.43%,均显著低于对照,种群趋势指数降低,表明对子代种群发展有一定的干扰作用。此外,虱螨脲处理小菜蛾雌、雄虫对其产卵量无影响,但处理雌虫显著降低卵孵化率,处理雄虫对卵孵化率无明显影响,说明虱螨脲作用于小菜蛾成虫,仅对卵子形成及受精卵的胚胎发育过程产生影响,而对精子的生成及转移无影响。表明虱螨脲可通过成虫取食或接触而控制小菜蛾种群发展。     

13种植物乙醇提取物对褐飞虱的生物活性研究

用冷浸法提取13种植物的乙醇提取物.在室内对灰飞虱成虫进行产卵忌避活性试验和对若虫进行触杀毒力试验.结果表明,水菖蒲乙醇提取物的产卵忌避作用最好,24 h的忌避率可达99.16%:肉豆蔻乙醇提取物次之,24 h的产卵忌避率为83.40%;花椒、石菖蒲、葫芦巴、水菖蒲、肉豆蔻等5种乙醇提取物对褐飞虱若虫的触杀作用明显,在83.70μg/cm2的计量处理下,24 h后的校正死亡率均达80%以上.     

黄色灯对小菜蛾成虫生物学的影响

研究了室内条件下黄色灯对小菜蛾成虫产卵量、产卵前期、产卵历期和成虫寿命的影响。结果表明,夜间施以黄色灯照射,小菜蛾群体和单管配对后成虫的产卵量均显著降低。同时,单管配对后成虫产卵率由对照组的70%下降到40%;小菜蛾雌成虫的产卵历期和寿命均缩短了2 d,而对其雄成虫的寿命影响不大。     

枣镰翅小卷蛾成虫的寄主趋向和产卵选择

采用固相微萃取(SPME)和GC-MS分析研究木枣和酸枣挥发物成分,并测试枣镰翅小卷蛾触角电位(EAG)反应、寄主趋向和产卵选择,以探明枣镰翅小卷蛾的寄主选择机制。结果显示,在萌芽期,木枣和酸枣嫩叶的挥发成分均为罗勒烯、2-甲基-2-菠烯、α-法呢烯和邻苯二甲酸二丁酯4种,但相对含量稍有不同。枣镰翅小卷蛾成虫对木枣和酸枣2种寄主都有强烈的EAG反应,且同一寄主上雌蛾的EAG反应值极显著地高于雄蛾,其EAG值是雄蛾的3.3倍。枣镰翅小卷蛾对木枣表现强烈的趋向反应,而对酸枣的趋向不明显,且雌虫的趋向反应显著高于雄虫。木枣上的产卵量显著高于酸枣,且木枣枣吊上的单雌产卵量为307.9粒,极显著地高于酸枣枣吊上的产卵量(182.9粒)。研究表明,枣镰翅小卷蛾雌蛾在寄主选择中起主导作用,木枣是其嗜好寄主。     

四种非寄主植物精油对小菜蛾的生物活性

为寻找小菜蛾Plutella xylostella绿色防控方法，于室内测定辣蓼、迷迭香、芸香和紫苏4种非寄主植物精油对小菜蛾的生物活性。结果表明，辣蓼植物精油对小菜蛾2龄幼虫的毒杀作用最强，24、48和72 h时的致死中浓度LC50分别为2.18、1.78和1.46μg/μL，芸香植物精油次之；当芸香植物精油浓度为15μg/μL时，小菜蛾3龄幼虫的选择拒食率最高，作用24 h和48 h时分别为100.00%和92.84%，而在10μg/μL浓度下作用24 h和48 h时非选择拒食率达到最高值，分别为65.72%和42.72%；在4种植物精油中，芸香植物精油对小菜蛾3龄幼虫的生长抑制作用最明显，相对生长率最低，为-34.72%，生长抑制率最高，为133.74%，辣蓼植物精油的生长抑制效果次之，迷迭香和紫苏植物精油的抑制作用相对较差；小菜蛾雌、雄成虫对4种植物精油均表现出一定的触角电位反应和驱避活性，其中，芸香植物精油的驱避效果最明显；气相色谱-质谱分析结果显示，芸香植物精油的主要成分为β-石竹烯、（+）-α-蒎烯和β-蒎烯。表明芸香植物精油对小菜蛾具有显著的生物活性，具备开发为小菜蛾靶标...     

家用调料植物粗提物防治小菜蛾的研究

以安全性和简易性为前提的庭园害虫防治成为休闲生活不可或缺的技术。本文以花椒Zanthoxylum bungea-num、八角茴香Illiciu mverum、辣椒Capsicum frutescens等日用品为材料,研究了不同种类、浓度和作用时间对小菜蛾Plutella xylostella这一重要庭园害虫的拒食、触杀及产卵忌避效果。拒食试验表明,供试3种植物对小菜蛾有显著拒食作用,拒食率从大到小依次为八角茴香(0.94)、花椒(0.86)、辣椒(0.76);拒食率随处理时间长短变化的差异不显著,但随提取液浓度的升高而升高。触杀试验表明,供试3种植物对小菜蛾有显著触杀作用,24h内死亡率从大到小依次为花椒(45.6%)、八角茴香(35.6%)、辣椒(23.3%),均显著高于对照处理的1.1%;触杀死亡率随虫龄的增加而降低。产卵忌避试验表明,3种植物对小菜蛾成虫产卵忌避作用由大到小依次为辣椒、八角茴香、花椒。综合本研究所得结果来看,八角茴香对小菜蛾的控制效果最好。所选材料容易获得,对小菜蛾忌避作用明显,在庭园小菜蛾防治中具有潜在的应用价值。     

Investigation of the Mode of Action of Nematode Neuropeptides

The neuropeptide AF2 has a complex set of actions on the dorsal muscle strip of Ascaris suum, including a potentiation of the acetylcholine-stimulated muscle contraction. Caffeine at 100 μm and 5 mm inhibited this potentiation, as did 100 μm theophylline in two out of six studies. The cyclic-AMP-potentiating compounds IBMX, dibutyryl cAMP and forskolin had no effect on the AF2-induced potentiation of the acetylcholine-stimulated muscle contraction. These preliminary data suggest that the potentiating action of AF2 is not mediated by a cAMP pathway.     

厚朴病虫害种类的初步调查

采用标准地法和线路调查法,对湖北恩施市新塘乡双河厚朴基地的厚朴病虫害进行了系统调查,记录主要虫害13种,其中叶部害虫9种,枝干害虫2种,根部害虫2种。厚朴主要病害5种。藤壶蚧、厚朴枝角叶蜂和厚朴新丽斑蚜为湖北省首次报道,小绿叶蝉为厚朴新寄主记录种。同时记录了藤壶蚧的天敌6种,其中寄生小蜂2种,瓢虫4种;厚朴新丽斑蚜的天敌昆虫8种。对藤壶蚧、厚朴枝角叶蜂和厚朴苗木根腐病等重要病虫害的发生规律进行了初步调查,同时提出了防治建议。     

Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato

The effects of timing and method of application of Penicillium oxalicum on the control of fusarium wilt of tomato were investigated. Application of P. oxalicum to tomato seedlings in seedbeds reduced disease caused by Fusarium oxysporum f.sp. lycopersici in a growth chamber by 45–49% and in glasshouse experiments by 22–69%. Disease suppression was maintained for 60–100 days after inoculation with the pathogen in the glasshouse. No disease reduction was observed in tomato plants where P. oxalicum was applied to seeds. Treatment with P. oxalicum did not affect the population of F. oxysporum f.sp. lycopersici in the rhizosphere.     

棉花黄萎病菌致病型的AFLP分析

 选用41个棉花黄萎病菌(Verticillium dahliae)代表菌系,在温室条件下,对4个棉花品种鄂荆1号(感)、中棉所12(耐)、文-5(抗)和唐棉2号(抗)进行致病性测定,结果可将供试菌系分为落叶型与非落叶型2类。选取8对AFLP引物PCR扩增的结果中,统计带型稳定、清晰且有多态性的条带,共169条作系统聚类分析,将上述菌系分为2大类,第一类为非落叶型菌系,包括10个非落叶型菌系和1个过渡菌系;第二类为30个落叶型菌系。根据聚类分析建立树状图,发现菌系与地理来源存在一定的相关性,而依据菌系致病力强弱分类则相关关系不大。选用25对EcoRⅠ和MseⅠ引物组合,对供试的41个V.dahliae进行AFLP扩增,筛选到2对引物E64(GACTGCGTACCAATTCGAC)、M53(GATGAGTCCTGAGTAACCG)和E49(GACTGCGTACCAATTCCAG)、M65(GAT-GAGTCCTGAGTAAGAG),能分别扩增出433bp和110bp2条仅为V.dahliae非落叶型菌系独有的特异片段,可将落叶型与非落叶型菌系分开,这2条特异片段被命名为EM₄₃₃和EM₁₁₀。     

百合地下害虫主要种类调查及生物（源）农药筛选

调查了甘肃省临洮县为害百合的地下害虫种类, 并以主要发生为害种类为供试对象, 采用拌土法测定了几种生物（源）农药对主要害虫的室内毒力和致死中时。调查发现小云斑鳃金龟Polyphylla gracilicornis、棕色鳃金龟Holotrichia titanis为主要发生及为害种类, 不同时间发生种类存在差异, 9月份以小云斑鳃金龟幼虫发生为害为主, 发生量占地下害虫总数的66.16%, 平均种群密度为10.48头/m2, 10月份, 则以棕色鳃金龟幼虫发生为主, 发生量占地下害虫总数的96.86%, 平均种群密度为7.79头/m2, 主要取食百合根系和鳞茎, 造成根系数量减少, 鳞茎出现不规则褐色缺口或凹陷斑。药剂筛选结果表明, 1.8%阿维菌素乳油、200亿孢子/g球孢白僵菌粉剂对两种蛴螬均具有较高的杀虫活性和速效性, 药后7 d时, 校正死亡率在82.22%以上, 对小云斑鳃金龟幼虫和棕色鳃金龟幼虫的LC50分别为0.161、0.060 mg/g和5.558×107、0.362×107孢子/g, LT50分别为2.237 d（2.2 mg/g）、1.393 d（2.2 mg/g）和6.645 d（40.0×107孢子/g）、4.940 d（2.0×107孢子/g）, 这两种生物（源）农药对两种蛴螬的LC50和LT50值均略大于两种化学农药25%二嗪磷乳油、40%辛硫磷乳油处理的, 且对小云斑鳃金龟幼虫的杀虫活性均低于对棕色鳃金龟幼虫的杀虫活性, 致死中时则长于对棕色鳃金龟幼虫的致死中时。     

Mode of action of etoxazole

The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition.     

青稞种子带菌检测及杀菌剂消毒处理效果

为了研究青稞种子外部和内部携带真菌情况,比较不同杀菌剂对青稞种子的带菌消毒效果和对幼苗生长的影响,为青稞种子播前包衣处理和种传真菌病害防控提供依据,采用离体平皿法对云南迪庆‘云青1号’、‘云青2号’和‘短白青稞’3个主栽品种进行带菌检测,并对种子进行拌种或浸种处理测定6种杀菌剂对种子消毒效果,分析杀菌剂对种子发芽和幼苗生长的影响。结果表明:供试青稞种子表面携带的优势菌群为青霉(Penicilliumspp.)、镰刀菌(Fusariumspp.);种子内部寄藏的真菌主要为镰刀菌、核腔菌(Pyrenophoraspp.)、附球菌(Epicoccumspp.)、丝核菌(Rhizoctoniaspp.)、链格孢(Alternariaspp.)和木霉(Trichoderma spp.)。青稞不同品种的种子表面及内部携带的真菌种类差异较大。致病性测定表明,镰刀菌对种子萌发和幼苗生长影响最大,后期出现幼苗坏死现象。45%咪鲜胺EW、75%百菌清WP、50%福美双WP对青稞种子携带真菌均有显著抑制作用和消毒效果,50%福美双WP消毒效果最优,达100%;45%咪鲜胺EW、75%百菌清WP、50%福美双WP处理对青稞种子发芽和幼苗生长均无显著影响。     

黑麦草属DNA条形码鉴定技术研究

以毒麦、田毒麦、多花黑麦草、多年生黑麦草、硬直黑麦草、高羊茅与狗牙根等禾本科的7种植物为材料,拟采用 DNA 测序、特异性位点比对、种间遗传距离测定、建立系统树等分析候选 DNA 条形码 psbA-trnH 鉴别黑麦草属常见植物的能力。实验结果表明,以 psbA-trnH 为 DNA 条形码时,建立的系统发育树能较好区分毒麦和田毒麦与其他几种植物。psbA-trnH 序列可以作为黑麦草属植物的潜在条形码。     

Effects of different temperature treatments on dormancy of sclerotia of ten isolates of Sclerotium cepivorum

The variability of dormancy of sclerotia of ten isolates ofSclerotium cepivorum was investigated. Of all isolates tested, the freshly harvested sclerotia were dormant. After drying for 48 hours the sclerotia of six isolates were able to germinate, two isolates stayed dormant and two isolates were infested by hyperparasitic fungi. After storage in soil at 5°C or 20°C, the sclerotia of the different isolates exhibited considerable differences in respect to germination capability, but all isolates showed highest germination after a treatment of 8 weeks at 20°C followed by 8 weeks at 5°C. The sclerotia of all isolates showed an increased capacity to germinate withoutAllium extracts at 10°C after pretreatment at 30°C for 28 days.     

Allelopathy of buckwheat: Assessment of allelopathic potential of extract of aerial parts of buckwheat and identification of fagomine and other related alkaloids as allelochemicals

The allelopathic potential of buckwheat ( Fagopyrum esculentum ) was investigated. Field study showed that living buckwheat reduced weed biomass compared with plots without buckwheat. Laboratory study revealed that root exudates suppressed root and shoot growth of weeds and reduced weed dry weight. Sequential partitioning of the aqueous ethanolic extract of the aerial parts of buckwheat showed that the chloroform extract caused an 80% reduction in radicle elongation of lettuce seedlings at a concentration of less than 100 p.p.m. Fagomine, 4-piperidone and 2-piperidinemethanol were isolated and identified by ¹H and ¹³C nuclear magnetic resonance from the chloroform extract. These compounds caused a 50% inhibition of radicle elongation in lettuce seedlings at concentrations of less than 100 p.p.m. These results suggest that compounds 1, 2, and 3 might act as allelochemicals and affect the growth or germination of different plant species.