闽南番石榴树冠节肢动物群落的结构和动态

2006年8月至2007年8月对惠安番石榴园树冠节肢动物群落结构特征及群落特征的时序动态进行了研究。结果表明,树冠节肢动物共采集到2纲、16目、100科总计218种,其中害虫116种、天敌61种、中性昆虫41种。害虫优势种为桔小实蝇Bactrocera dorsalis(Hendel)和棉蚜Aphis gossypii Glover,天敌优势种为细纹猫蛛Oxyopes macilentus L.Koch和大草蛉Chrysopa septempunctata Wesmael。节肢动物群落的物种丰富度、个体丰盛度、多样性指数、均匀度指数和优势集中性指数等特征随季节的更替发生波动。     

茶园绿肥多花木兰冠层节肢动物群落结构分析

本文对茶园绿肥多花木兰冠层节肢动物群落结构进行初步调查,结果共采集到节肢动物5018头,其中以不危害植物的中性昆虫的数量最多（2968头）,占群落物种个体总数的59.15%;其次是肉食性天敌的数量（1106头）,占群落总个体数的22.04%;植食性害虫的数量（929头）第三,占群落总个体数的18.51%。群落多样性指数以6～7月较高,12月份较低,植食性害虫和肉食性天敌的个体数呈极显著的正相关。初步结果显示多花木兰适于在茶园边坡、路旁种植。     

安徽省沿江植棉区直播棉田节肢动物群落多样性时间格局

采用直接观察法,分析比较了直播棉田的节肢动物群落、害虫和天敌亚群落的结构组成及其多样性特征指数,并对其时间动态进行聚类。结果表明,安徽省沿江棉区直播棉田节肢动物群落共有13目43科56种。节肢动物总群落多样性指数和物种丰富度分别高于害虫亚群落和天敌亚群落,总群落的优势集中性指数和优势度在6月份以后分别低于害虫和天敌亚群落。害虫、天敌亚群落与总群落的多样性特征指数变化趋势较一致。害虫亚群落的优势集中性指数在5月和9月中下旬高于天敌亚群落和总群落。经系统聚类可将该类棉田害虫和天敌亚群落的时间动态分为4个阶段:棉花苗期群落、蕾花期群落、花铃期群落和吐絮期群落;棉花蕾花期是棉田害虫重点防治时期。     

伞房决明与茶树冠层害虫及天敌调查与动态分析

对伞房决明冠层和茶冠层的节肢动物群落进行系统调查,在伞房决明冠层共采集到节肢动物10182个个体.其中:中性昆虫个体数最多6590只,占群落物种个体数的64.72％,极显著高于茶冠层;植食性害虫共采集到2285只,占群落物种个体总数的22.44％;天敌1307头,占群落物种个体总数的12.84％.与茶冠层相比,极显著提...     

芒果园种植大叶油草对果园节肢动物群落结构及多样性的影响

为探究生草大叶油草种植对芒果园节肢动物群落的影响,将种植大叶油草的芒果园与传统清耕生境节肢动物群落结构进行比较,对2种不同生境2018年8月—2019年6月的节肢动物群落物种数量、物种多样性、群落稳定性进行了分析。结果表明,大叶油草生境下芒果园节肢动物物种数量、个体数量约为清耕生境的2倍;物种多样性指数、群落稳定性显著高于清耕生境,在天敌亚群落方面也表现出相似差异。而害虫亚群落方面,清耕生境害虫数量（4730头）约为大叶油草生境（2027头）的2倍。综合分析表明,芒果园种植大叶油草有利于增强节肢动物群落稳定性,减少害虫、提高天敌的种群数量、便于发挥天敌的自然控制作用,是一种较好的绿色防控措施。     

玉米田昆虫群落的结构及时序动态研究

2008年6月6日至2008年9月23日系统调查了夏玉米田主要害虫及天敌的种类和数量动态变化,并运用物种丰富度、优势度、多样性指数和相似性指数、相异性指数分析了昆虫群落的结构和时序动态。结果表明,在夏玉米田共有害虫和天敌11目32科44种;玉米蚜[Rhopalosiphummaidis(Fitch)]为玉米害虫群落中的最优势种,优势度指数为0.0002～0.3889;多样性指数在2008年8月7日和2008年8月21日达到两个高峰值;害虫及天敌在时间上的同步性和在空间上的同域性一致,为保护利用天敌、控制玉米的害虫提供理论依据。     

松墨天牛对马尾松林节肢动物群落数量分布的影响

分析了松墨天牛（Monochamus alternatusHope）对马尾松（Pinus massonianaLamb.）林分节肢动物群落的影响。结果表明：随松墨天牛危害程度加重,马尾松林分中节肢动物的物种数和个体数明显下降,其捕食性、植食性功能群种类和个体数及寄生性天敌个体数明显减少;松墨天牛危害对灌木草本层节肢动物种类和数量影响最大,在重度危害林分中,灌木草本层的节肢动物多样性指数H′和优势集中性指数J均显著低于轻度危害林分中的指数;受松墨天牛危害后,林分中稳定性指数S1/S2和N1/N2显著下降,马尾松林分中节肢动物的多样性和稳定性及其天敌对害虫的制约潜能显著降低。     

不同景观条件对棉田生物群落和多样性的影响

 从棉田节肢动物的个体总数、物种数、害虫数和天敌数等种群和多样性指数、均匀性指数和优势集中性等方面进行了较为详细的比较,初步明确了不同景观条件对棉田主要害虫及其天敌种群数量有一定的影响,对棉田昆虫个体总数和天敌种类数有较大的影响,对物种数和害虫种类数没有明显的影响,对棉田昆虫多样性、均匀性和优势集中性影响较大。     

管理模式对4类茶园节肢动物群落时空格局和多样性影响

选择树龄相同、品种为安吉白茶而栽培管理模式不同的有机茶园、三行密植茶园和丰产茶园,以及种植安吉白茶和龙井43等40多个品种的茶树品种园,通过在1周年内每2月1次的调查,发现：①从品种园、有机茶园、三行密植茶园至丰产茶园,天敌种数和个体数递减;三行密植茶园总个体数最大。②在垂直分层上：天敌种数和个体数在丰产茶园、三行密植茶园和品种园中皆以中层最多,在有机茶园中则以上层最多;害虫种数在丰产茶园、三行密植茶园和品种园中以中层最多,在有机茶园中以上层最多;害虫个体数在丰产茶园和三行密植茶园以下层最多,在品种园和有机茶园以中层最多;③在水平分布上,除了品种园,其他3类茶园东、西向天敌种数之和、个体数之和分别大于南、北向天敌种数之和、个体数之和;④在茶丛内、外层,4类茶园皆以内层害虫种数和个体数略多;外层天敌种数和个体数略多;⑤12月至翌年2月的越冬期间,物种数相对较少;4月、6月和10月物种数相对较多;⑥从有机茶园、品种园、丰产茶园至三行密植茶园,多样性指数递减。分析认为：尽管树龄、品种等相同,但是一个时期以来的不同管理模式可导致4类茶园节肢动物群落时空格局和多样性的显著差异,在一定程度上调控着昆虫群落结构和多样性。     

单季稻田节肢动物群落演替规律

 运用种类丰富度、数量、申农指数等指标,对浙江省富阳市的稻田节肢动物群落的演替过程进行了描述、分析。可将整个演替过程划分为扩展期、波动期、衰减期三个时段,依据对水稻的不同作用性质将节肢动物群落分为天敌、害虫、中性昆虫三个亚群落。从以上三个指标的分析结果来看,三种亚群落的演替过程具有不同步性。相比而言,天敌亚群落具有最高的丰富度和多样性,其贡献率几乎达到50%;中性昆虫亚群落与害虫亚群落三个指标的每周累加值具有相似性,但数量消长呈负相关性。     

海南不同市县旱田代表性杂草发生规律研究

为全面了解海南不同市县旱田代表性杂草全年的发生规律,从2008年至2009年,采用全年定点、定时观测的方法对海南7个市县杂草自然萌发情况进行调查。结果表明:海南不同市县定点观测样方里共有代表性杂草20科60种,其中菊科、禾本科、苋科、豆科和茜草科较多,占杂草总数的63%;外来入侵杂草有29种,占总数的48%;重要值大于5的优势种杂草有12种,占所有杂草的20%。6月是杂草种类萌发高峰,达15种。海南杂草年平均萌发量达1 060株/0.25 m2,其中万宁最高,年平均萌发量达1 559株/0.25 m2;定安最低,年平均萌发量达519株/0.25 m2。海南杂草全年发生数量有两个高峰期:一个在4月,萌发率为16%;一个在9月,萌发率为10%。全年大部分杂草在3~7月和9月萌发,萌发率为全年的70%。在海南,温度均能满足杂草萌发需要,降雨量是杂草发生的主要限制因子。     

不同牧草混播方式对冬闲田杂草发生及种类的影响

为了解冬闲田播种的不同种类牧草田的杂草群落发生动态，调查了30％黑麦草＋70％白三叶，30％黑麦草＋70％紫云英，30％黑麦草＋70％紫花苜蓿，3种不同牧草混播处理下冬闲田杂草的生长特点。结果表明：牧草混播种类的变化使冬闲田杂草的发生有差异，主要表现为杂草种类和危害程度不同，其中以30％黑麦草＋70％紫云英处理下的冬闲田杂草危害程度最低。     

稻作区灌溉水流传播的杂草种子与稻田土壤杂草种子库的关系

选择典型稻作区,对灌溉水流传播的杂草种子的种类和数量进行取样调查,并与田埂、灌溉水渠周围生境、下茬麦田的杂草群落及稻田土壤杂草种子库进行比较分析,以研究自然条件下灌溉水流传播的杂草种子与土壤杂草种子库及其他生境杂草群落间的相互关系。 有14科21种杂草种子随灌溉水流输入稻田,这些杂草种子主要隶属禾本科、报春花科、藜科、蓼科等。土壤杂草种子库中共检出19科41种杂草种子,含有所有其他生境中杂草的种子。灌溉水流传播的杂草种子与田埂上、灌溉水渠周围生境、下茬麦田杂草群落及稻田土壤种子库的杂草群落间相似性较高,Sorensen指数均在0.5以上。     

泰山茶园害虫种类调查及主要害虫种群动态研究

为明确泰山茶园害虫种类及主要害虫种群动态,进行了系统调查,结果表明茶园害虫43种,分属2纲7目27科.主要害虫有小贯小绿叶蝉、茶蚜、黑刺粉虱及绿盲蝽.小贯小绿叶蝉全年有2个高峰期,分别在6月上旬和8月上旬;茶蚜全年有2个高峰期,在5月上旬和9月中上旬;黑刺粉虱从4月初至11月初,各种虫态均可见;绿盲蝽的盛发期在5月份.     

苏北垦区豆田杂草生长为害习性

苏北垦区豆田杂草分属15科,36属,41种,恶性杂草有稗,苍耳等9种。在大豆整个生育期间通常出现1～2个萌发高峰,主要集中在6月中旬～7月下旬。杂草种子于8～10月成熟。种子在土壤中的埋深及出苗期,直接影响杂草的出苗和繁殖。杂草与大豆的相互竞争,以在大豆播种一个月后最为剧烈。0～2cm和6～25cm耕层中贮葳的杂草种子最多。     

Distribution of tobacco rattle virus and potato virus X in leaves,roots, and fruits and/or seeds of naturally-infected weeds

Weeds in tobacco rattle virus (TRV)-infested potato fields were examined for TRV and potato virus X (PVX) with the enzyme-linked immunosorbent assay. Questionable positive reactions were evaluated with immunosorbent electron microscopy. Of 615 weeds, representing 28 species, sampled over a two-year period, four species contained only TRV, three were infected only with PVX and eight had both viruses. Tobacco rattle virus was located only in the roots of five species and PVX was found only in the foliage of five species. Seeds and/or fruits of three species contained TRV while two contained PVX. Only one weed species,Solanum sara choides, contained both viruses in all plant portions tested. Potato virus X was not detected in weeds within a field planted with PVX-free potato seed.     

Four years validation of decision support optimising herbicide dose in cereals under Spanish conditions

The Danish decision support system Crop Protection Online (CPO) optimises herbicide weed control. CPO recommends specific herbicide solutions to achieve a required level of control. The aim is to apply herbicides as little as possible but as much as necessary. CPOWeeds is a version of CPO adjusted to conditions in North-eastern Spain. The predicted efficacies and the yield obtained with CPOWeeds were validated in winter cereal field trials from 2010 to 2013. All CPOWeeds treatments were related to the efficacies obtained with standard herbicide treatments decided upon by local advisors. The predictions from CPOWeeds were compared to the actually achieved efficacies in the field trials for the nine weed species at different developmental stages and for 84.2% of the comparisons the obtained efficacies were equal to or higher than predicted. The average difference between predicted and observed efficacies was 2.35 percentage points. Yield was measured in three trials and the recommendations from CPOWeeds were maintaining yield. There were two situations where CPOWeeds were performing suboptimal. One is in the early weed growth stages, as the model is not yet prepared to account for water stress on root action herbicides applied at 10-11 BBCH. The second situation was in fields with a prior unidentified population of resistant Alopecurus myosuroides. For key species in winter cereals in Spain, such as Avena sterilis, Lolium rigidum and Papaver rhoeas, CPOWeeds achieved a satisfactory control level. It was concluded that the use of CPOWeeds allowed optimisation of the herbicide application with a very high robustness. The recommendations were satisfactorily for the conditions of the Northeast of Spain and have the potential to decrease the amount of applied herbicides by at least 30%. Therefore, it can be an important tool in Integrated Weed Management.     

Population Dynamics of Empoasca fabae (Hemiptera: Cicadellidae) in Central Iowa Alfalfa Fields

Adults and nymphs of Empoasca fabae Harris (Hemiptera: Cicadellidae) and adults of predatory species in the families Coccinellidae, Anthocoridae, Nabidae, Chrysopidae, and Hemerobiidae were sampled in Iowa alfalfa fields from June to September in 1999 and 2000. The relationship between each predatory taxa and E. fabae was examined using regression analysis. In 2000, all predators were found to be positively correlated with the presence of E. fabae during all periods sampled and most likely contributed to mortality. Orius insidiosus (Say) (Hemiptera: Anthoridae) was the most numerous insect predatory species; population numbers ranged from 0 to 1 and 0.1 to 3.7 adults per 0.25 m² in 1999 and 2000, respectively. Partial life tables were constructed for E. fabae nymphs for two alfalfa-growing periods. Nymphs were grouped into three age intervals: first and second, third and fourth, and fifth instars. For the first alfalfa growing period examined, E. fabae nymphal mortality was 70% in 1999 and 49% in 2000. During the last growing period of each season (August–September), total nymphal mortality was relatively low (<25%). Adult E. fabae density ranged from 5.4 to 25.6 and 1.4–9.2 per 0.25 m² in 1999 and 2000, respectively. E. fabae population peaks were similar for each age interval in all growing periods. This study provides further information on the population dynamics of E. fabae and its relationship with select predatory species in Iowa alfalfa fields.     

Effects of water-saving irrigation on weed infestation and diversity in paddy fields in East China

The purpose of the article is to investigate the effects of water-saving irrigation on weed infestation and diversity in paddy fields; a two-year field experiment was conducted in Gaoyou Irrigation District, China. The responses of two irrigation treatments, controlled irrigation (CI) and traditional irrigation (TI), were observed and compared. The irrigation water use, yield, weed density, coverage ratio, height, species richness, density, dominant species, Shannon–Wiener index, and Pielou index were examined to analyze the water productivity, weed infestation, and diversity in paddy fields under the two treatments. The results showed that the water conditions were similar before the late tillering stage, and thereafter the CI fields were alternatively dry and wet with shallow standing water and low soil water content, while the TI fields were mostly continuously flooded by deep standing water and high soil water content. Irrigation water use for CI was 46.8% lower than TI. The CI treatment reduced weed density by 38.0%, decreased coverage ratio by 13.8%, and resulted in a 39.0% increase in weed height. Fewer species were found in CI fields than TI fields. The Shannon–Wiener index decreased by 11.5%, and the Pielou index increased by 3.2%. The changed water regime under CI not only impeded the growth of dominant species but also placed the whole weed community at a relatively stable level with reduced weed density. Meanwhile, aquatic weeds were well controlled; however, semi-aquatic weeds became the dominant species. In general, CI effectively reduced the risk of weed outbreaks, and weed diversity also decreased when it reduced irrigation water use.