稻田蜘蛛对弹尾虫的功能反应及选择作用

作者在室内研究了拟环纹豹蛛和草间小黑蛛对弹尾虫的功能反应和选择作用。结果表明,两种蜘蛛对弹尾虫的功能反应均为Ⅱ型反应,并存在极显著的差异,拟环纹豹蛛对弹尾虫的功能反应明显强于草间小黑蛛,其对弹尾虫的控制作用（ａ／Ｔｈ＝３９．７５８）是草间不黑蛛（１３．０３１）的３倍左右。弹尾虫和白背飞虱共存时,两种蜘蛛的功能反应变为Ⅲ型反应,并对弹尾虫都具有明显的偏好性,弹尾虫的存在降低了两种蜘蛛对白背飞虱的捕食     

弹尾虫特征特性及其对经济作物的危害

弹尾虫虫体微小、种类丰富、分布广泛。近年来发现该虫对食用菌、天麻、姜、蒜、百合、芋头等多种经济作物为害严重。本文详细介绍了弹尾虫的外部形态特征、生物学特性及其对经济作物的危害。     

两种稻田蜘蛛对褐飞虱的捕食作用试验

经室内测试 ,八斑鞘腹蛛和柔弱锯螯蛛对褐飞虱的最高日捕食量分别为 5.7± 0 .5头 ,5.3±0 .9头 ,差异不显著。但柔弱锯螯蛛的Q/Th值较大 ,干扰系数较小 ,表明柔弱锯螯蛛对褐飞虱的控制能力较强 ,相互间的干扰程度较小 ,因此 ,在一定条件下的应用效果将会更好     

异色瓢虫对桃大尾蚜的捕食作用研究

测定了异色瓢虫 2龄、4龄幼虫和成虫对桃大尾蚜捕食功能反应及自干扰作用 ,结果表明其功能反应属于Holling-Ⅱ型圆盘方程式 ,寻找效应与自身密度的关系可用Hassell数学模型描述。异色瓢虫对桃大尾蚜具有较强的捕食能力 ,对猎物的寻找效应随着自身密度的增大而下降。模拟后的各方程理论值与实测值经X² 检验差异不显著     

食虫齿爪盲蝽对枸杞木虱的捕食作用研究

在室内研究了捕食性天敌食虫齿爪盲蝽成虫对枸杞木虱2龄若虫的捕食作用。结果表明,食虫齿爪盲蝽对枸杞木虱的捕食功能反应符合HollingⅡ型反应,拟合的圆盘方程为Na=0.964 9N/(1+0.313N)。捕食木虱数量随木虱密度增加而增大,但寻找效应随之而降低。食虫齿爪盲蝽对自身密度的功能反应用Watt模型拟合为A=43.089 0P-0.780 5,其捕食作用率与个体间相互干扰作用的关系用Hassell-Varley的干扰反应模型拟合为E=0.5394P-0.378 7,饥饿48 h的食虫齿爪盲蝽的捕食速度与时间段关系的数学模型为V=2.128 1x-1.007 2。     

红基盘瓢虫对柑桔木虱捕食作用的研究

用Holling—Ⅰ型和Holling—Ⅱ型功能反应模型对红基盘瓢虫Lemia circumusta雌成虫、雄成虫、四龄幼虫捕食柑桔木虱若虫的作用进行拟合,得出功能反应的数学模型分别为:雌成虫对柑桔木虱若虫的捕食率随自身密度的增加而降低。     

山西壶瓶枣缩果病病原菌分离和鉴定

 2005~2008年山西壶瓶枣缩果病害发生严重,造成了巨大的经济损失。本文利用真菌ITSrDNA和细菌16S rDNA基因的通用引物,分别对分离自山西晋中的罹病壶瓶枣果实表面寄生真菌和细菌基因组DNA进行PCR扩增,将扩增产物进行核苷酸序列测定,在GenBank数据库进行Megablast同源性分析,确定壶瓶枣果实的主要寄生菌是细极链格孢菌(Alternaria alternata)、白囊耙齿菌(Irpex lacteus)、青霉菌(Penicillium expansum)、芽枝孢菌(Cladosporium tenuissimum)4种真菌和枯草芽孢杆菌(Bacillus subtilis)、巨大芽孢杆菌(B.megaterium)、短小芽孢杆菌(B.pumilus)、多粘类芽孢杆菌(Paenibacillus polymyxa)4种细菌。回接试验证明链格孢菌、青霉菌、芽枝孢菌是壶瓶枣果实主要的致病真菌,而所分离的细菌没有致病性。     

盘锦稻区蜘蛛群落的建立与多样性分析

采用吸虫器抽吸法,系统调查了盘锦稻区蜘蛛物种组成及群落的建立过程,并分析了单季稻区蜘蛛群落多样性特点。结果表明,盘锦稻区共采集到10科37种蜘蛛,种类较丰富,其中横纹金蛛Argiope bruennichii、粽管巢蛛Clubiona japonicola和草间钻头蛛Hylyphantes graminicola 3种为优势种蜘蛛。随着水稻插秧,蜘蛛逐渐从非稻田生境向稻田生境迁移,至8月上旬(8月10日前后),种类数达到最大值26种,完成群落建立过程。Shannon-Wiener指数表明,6月初蜘蛛多样性水平最低,8月下旬蜘蛛多样性水平最高,指数最高值为3.0697,而均匀度指数、丰富度指数与其呈正相关,优势度指数与其呈负相关。     

化防田与综防田蜘蛛群落物种组成及优势类群动态分析

洞庭湖平原地区共有稻田蜘蛛10科27属41种,其优势种为拟水狼蛛、食虫沟瘤蛛、八斑鞘腹蛛和锥腹肖蛸。在两类防治田的早稻田中,蜘蛛优势种没有变化,主要为拟水狼蛛和食虫沟瘤蛛;晚稻田中,蜘蛛优势种存在更替现象。在综防田和化防田中,蜘蛛种类和个体数量存在较大差异。同时,对蜘蛛控制害虫生物量进行了定量测定。     

华北大黑鳃金龟成虫周年发生动态及影响因素分析

华北大黑鳃金龟[Holotrichia oblita(Faldermann)]是一种为害多种作物的重要地下害虫,为了解其近年的发生动态以便针对性防治,于2010-2013年对其成虫出土规律进行了周年系统研究,并对其发生期和发生量影响因素进行了初步分析。结果表明,2010-2013年华北大黑鳃金龟的出土盛期仍在5月份,与文献相比总体一致,但出土期略滞后并且时间有所延长;而2013年始发期明显晚于其他年份,对其气象因素分析发现,2013年春季干旱,首次降雨在5月26日,明显晚于其他年份,其始发期也较其他年份偏晚,说明土壤湿度可能影响成虫出土始期。出土盛期成虫出土量与气象因素的灰色关联度分析表明,成虫日出土量与平均相对湿度关联最密切,其次是日均温和降雨量。研究结果为华北大黑鳃金龟的预测预报以及针对性防治提供了基础。     

Molecular characterization and diagnostics of stubby root and virus vector nematodes of the family Trichodoridae (Nematoda: Triplonchida) using ribosomal RNA genes

Plant parasitic nematodes of the family Trichodoridae cause substantial yield losses in many agricultural crops. Rapid and accurate identification of trichodorids to the species level is critical for selection of appropriate measures for control. This study analysed 99 sequences of the D2–D3 expansion segments of the 28S rRNA gene and 131 sequences of the 18S rRNA gene from the stubby nematodes belonging to the genera Nanidorus, Paratrichodorus and Trichodorus. Species delimiting was based on the integration of morphological identification, which is not provided in the present article, and molecular‐based phylogenetic inference and sequence analysis. Twenty‐two valid species and several species complexes were identified among nematodes included in the analysis. PCR‐RFLPs of the partial 18S rDNA and the D2–D3 expansion segments of the 28S rDNA were tested and proposed for identification of these nematodes. Gel PCR‐RFLP profiles and tables with restriction fragment lengths for several diagnostic enzymes are provided for identification. Some problems of taxonomy and phylogeny of nematodes of the family Trichodoridae are also discussed.     

Phylogenetic analysis of the citrus Huanglongbing (HLB) bacterium based on the sequences of 16S rDNA and 16S/23S rDNA intergenic regions among isolates in China

Phylogenetic analysis of Chinese isolates of the citrus Huanglongbing (HLB) bacterium based on the 16S rDNA and 16S/23S rDNA intergenic regions sequences was carried out. Nine HLB samples collected from different hosts with different symptoms in seven Chinese provinces, were subjected to PCR for amplifying and sequencing the 16S rDNA. The identity level among Chinese isolates was 98.5% to 100% and was the same with the Indian HLB isolate ‘Poona’ (GenBank accession number: L22532). By contrast, identity values were 97.5% to 97.8% with Candidatus Liberibacter africanus strain ‘Nelspruit’ (L22533), 96.3% to 97.3% with Ca. L. africanus subsp. ‘Capensis’ (AF137368), 95.3% to 96.5% with the Ca. Liberibacter sp. ‘LSg2’ (AY919312), and 94.9% to 96.0% with a strain of Ca. L. americanus from Brazil (São Paulo State; AY742824). A phylogenetic tree constructed with 16S rDNA sequences showed that all Chinese isolates belong to Ca. L. asiaticum. Analysis of the 16S/23S rDNA intergenic region was conducted on 18 HLB-diseased citrus samples with different symptoms, collected in seven provinces. These isolates showed no obvious variation and had an identity level >99.0% with one another. Sequence analysis of 16S/23S rDNA intergenic region and the relative phylogenetic tree showed that the Chinese isolates are very close to Ca. L. asiaticus, and distinct from Ca. L. africanus and Ca. L. americanus. These results suggest that the Chinese HLB isolates belong to the species Candidatus Liberibacter asiaticus. This is the first report on the classification of HLB isolates from China based on molecular investigations.     

云南烟草上1种新的细菌性病害病原鉴定

 2006~2007年在云南文山州的西畴县和保山市的昌宁县发现1种由细菌侵染引起的烟草新病害。主要发生在苗期(漂浮育苗)和移栽期,症状开始为白色至暗绿色小斑点、湿腐和茎上出现褐色斑点,在KB培养基上产生荧光。根据致病性、菌体形态、培养性状、生理生化反应、Biolog测试和16S rDNA序列分析将该病原菌鉴定为铜绿假单胞菌(Pseudomonas aeruginosa)。尽管该病害曾在菲律宾发生,但在中国尚属首次报道。     

氮肥缺失对旱地土壤细菌群落多样性的影响

本文旨在研究氮肥缺失对旱地土壤细菌群落多样性的影响.采用直接提取土壤微生物总DNA的方法,对不施肥(CK)、适量施肥(F1)、和缺氮施肥(F2)3种不同施肥水平土样DNA进行提取,扩增细菌16S rDNA基因片段,建立克隆文库.用限制性内切酶Hha I和Rsa I进行PCR-RFLP分析,分别得到146、187、11个酶切类型.采用α多样性的测度对试验结果进行分析统计结果表明,不同处理间土壤细菌的多样性(H′、Ds和Dg)和物种丰富度(dMa、R2和E)均为F1>CK>F2;λ、dMa、E和H′指数在不同施肥处理间的变异系数达到56.96%～163.1%,尤其Simpson指数λ是非常敏感的指标,处理间的差异最大,表明氮肥缺失严重影响土壤细菌群落多样性,合理施肥有利于土壤细菌的多样性.