纵坑切梢小蠹蛀梢期空间分布

在昆明地区,纵坑切梢小蠹(Tomicus piniperda)成虫蛀梢多集中在蛀干木附近。 种群密度以蛀干木为中心向周围呈指数递减,散布半径约30m。在蛀梢过程中,该种群逐渐向新区扩张。在树冠内,纵坑切梢小蠹主要分布在4-10轮枝上。第7轮枝虫口百分率最高。6-7轮枝受害率最大。 树冠上层受害较其下层严重。从树冠水平层次考察,树冠外层虫量相对集中,约为树冠中、内层虫量之和。 树冠内层虫量最少。纵坑切梢小蠹在树冠内的种群分布系由梢径、种群密度、蛀梢行为、降落方式、光照等因素综合影响的结果。     

纵坑切梢小蠹蛀梢期空间分布

在昆明地区,纵坑切梢小蠹（Ｔｏｍｉｃｕｓ　ｐｉｎｉｐｅｒｄａ）成虫蛀梢多集中在蛀干木附近。种群密度以蛀干木为中心向周围是指数递减,散布半径约３０ｍ。在蛀虹梢过程中,该种群逐渐向新区扩张。在树冠内,纵坑切梢小蠹主要分布在４—１０轮枝上。第７轮技虫口百分率最高。６—７轮枝受害率最大。树冠上层受害较其下属于重。从树冠水平层次考察,树冠外层虫量相对集中,约为树冠中、内层虫量之和。树冠内层虫量最少。纵坑切梢小蠹在树冠内的种群分布系由梢径、种群密度、蛀梢行为、降落方式、光照等因素综合影响的结果。     

沙棘木蠹蛾卵和幼虫空间分布的地统计学分析

沙棘木蠹蛾(H olcocerushippophaecolus Hua,Chou ,Fang et Chen)是近几年在内蒙古、辽宁、山西、宁夏和陕西等地大面积爆发的一种钻蛀性害虫,其危害发生在幼虫期,主要危害沙棘(H ippophae rhamnoidea)的根干部。为了有效地控制其危害,深入了解种群的空间结构,利用地统计学方法分析了两种受害程度不同的林分内沙棘木蠹蛾幼虫种群和重度受害林分内卵块的空间分布特性。结果表明:两种受害程度不同的林分内,沙棘木蠹蛾的危害具有显著差异,轻度受害林分内无虫样本所占的比例较大,达70 % ,而重度受害林分内不到2 0 % ;虫口密度在轻度受害林分内超过6头/株的只有6 .9% ,而重度受害林分内高达31.9%。根据全方向的变异函数曲线图分析得知:重度受害林分和轻度受害林分内幼虫种群的空间依赖范围分别为7.3m和87.4 18m,而局部空间连续性强度分别为0 .914和0 .178。重度受害林分内幼虫表现较强的空间聚集性,而轻度受害林分则表现为随机分布。在重度受害林分中,单株沙棘树上沙棘木蠹蛾卵块数量最多的为11个,最少的为1个,有卵株率达72 %。分别采用四种不同的理论模型来拟合卵块的实际变异曲线图,得知其全方向的变异函数曲线为指数型,空间依赖范围大小为3.6 m,局部空间连续性强度为0 .876 ,卵块在重度受害林分中呈现较强     

斜纹拟木蠹蛾在广州发生的生物学特征

本文报道了斜纹拟木蠹蛾Indarbela obliquifasciata在广州的发生和为害特征,对其形态和生物学特征做了阐述,表明该虫在广州一年发生一代,其取食寄主达18种,但主要寄主植物为羊蹄甲,其幼虫共6龄并以幼虫越冬。并对该虫的防治提出了建议。     

木麻黄木蠹蛾初步观察

木麻黄是广东沿海地区防护林的主要树种,对防风固沙、保障农业稳产高产起着极大的作用。近几年来,在造林较早的湛江市郊和电白县林带发现木蠹蛾为害极为严重。现将我们对此虫进行观察结果,并参阅原湛江地区林业局防冶站与原中南林学院森保六一级有关资料整理如下。     

沙棘灌丛林受害程度的预测模型

我国沙棘灌丛林目前的灾害可分为生物灾害和非生物灾害。生物灾害以沙棘木蠹蛾危害为主,是近几年在内蒙古、辽宁、山西、宁夏和陕西等地大面积爆发的一种钻蛀性害虫;非生物灾害主要是立地和气候因素,总体表现为沙棘生长衰退,甚至出现大面积枯死。对辽宁省建平县和内蒙古敖汉旗不同受害程度沙棘灌丛林进行抽样调查,共设50块标准地,分别调查沙棘死亡株率、有叶树冠比例、沙棘木蠹蛾危害株率和20cm根干部沙棘木蠹蛾虫口数等沙棘受害指标,同时调查记录坡向、坡位、坡度、树高、地径和林分密度等多项生跃环境因子。通过模糊综合评判法,对4种受害特征指标进行权重分配,并根据综合评判值的大小,将沙棘灌丛林的受害程度分为健康、轻、中和重4个等级,以坡向、坡位、坡度、树高、地径和林分密度为预测因子,分别构建沙棘灌丛林受害程度BP神经网络模型和Logistic模型,BP神经网络的拟合率达88．1％,预留样本检验准确率为75％,Logistic模型的概率一致率为69．4％。在其它条件相同的情况下,坡位对受害程度的影响是其它因素的4．93倍。     

荔枝两种茎蛀虫的研究

本文记载两种钻蛀荔枝树茎的害虫,荔枝拟木蠹蛾及相思拟木蠹蛾。它们是福建、广东、广西及云南等地的荔枝和其他热带、亚热带果树及林木的常见害虫,而我国大陆过去尚未有记载。已查悉寄主植物有无患子科的荔枝、龙眼,芸香科的柑桔类等24科42种类。 这些害虫的幼虫钻蛀树茎成坑道后,匿居其中,夜出食害树茎韧皮部,并以虫粪、木屑等在树皮上缀成隧道,以循避敌害;它们一年皆发生一代,只幼虫在坑道中越冬,4-5月间相继化蛹,4月下旬至7月上旬有成虫出现。卵块生于树皮上。幼虫多于树茎分叉处蛀害。 以666及DDT粉剂或油剂滴注坑道,以及以该药剂较高浓度的水悬液,于7-8月间喷布树茎虫害处,皆有甚好的防治效果。 华南各地荔枝产区,蠹害荔枝树茎的害虫,主要有隶属于鳞翅目,拟木蠹科(Metarbelidae)的荔枝拟木蠹蛾(Arbela dea Swinhoe)及相思拟木蠹蛾(Arbela baibarana Mats.)等两种。这些害虫发生普遍,被害的植株往往导致风折或严重削弱树势,尤以幼树受害更显著,需要加以防治。 鉴于这些害虫除致害荔枝外,尚加害其他多种热带、亚热带果树及林木,而我国大陆过去缺乏记载,为此,笔者将近十年(1952-1962)来累积的一些资料整理报导,冀供昆虫工作者参考。     

大蓑蛾生物学的初步观察

<正> 大蓑蛾Clania variegata Snellen又名棉避债蛾、大袋蛾、大背袋虫,属鳞翅目蓑蛾科(Psychidae),在彭泽棉区间断普遍发生,局部为害较重。为害多种树木,7—8月间迁往棉田,为害棉叶,取食上部叶片和嫩头,严重时可将嫩头和棉叶全部吃光,影响棉花生长,甚至造成棉株枯死。为了解其生物学特性和探索防治措施,现将调查观察结果简报如下。     

牛角花齿蓟马为害对苜蓿无性系根茎叶及同化产物分配的影响

为探索同化产物分配利用与苜蓿耐蓟马的关系,本试验以扦插的抗蓟马苜蓿无性系R-1和感蓟马苜蓿无性系 I-1为材料,研究不同虫口牛角花齿蓟马为害对苜蓿的抗性、根、茎和叶生长特性及可溶性糖含量的影响.结果表明: 随着虫口压力的增大,R-1和I-1苜蓿的受害指数升高;在相同虫口压力下,R-1苜蓿的受害指数显著低于I-1.受蓟马为害后,R-1和I-1苜蓿株高降低、叶面积减少、茎秆变细、节间长变短、节间数增加,根颈和主根直径加粗、侧根增多.在低虫口密度下,随虫口压力增大,R-1和I-1苜蓿地上部生物量增加,根冠比下降,分配到茎的生物量比例升高;在高虫口密度下,地上部生物量随虫口压力增大而减少,根冠比增加,分配到根系的生物量比例升高;R-1根冠比和茎生物量比例随虫口压力变化曲线的拐点均为每枝条5头,I-1根冠比和茎生物量比例随虫口压力变化曲线的拐点均为每枝条3头.在低虫口压力下,R-1苜蓿茎和叶中的可溶性糖含量随虫口压力增加而升高;在高虫口压力下,茎和叶中的可溶性糖含量随虫口压力增加而下降;根中可溶性糖含量随虫口压力增加持续下降.I-1根、茎和叶中的可溶性糖含量均随虫口压力增加持续下降.牛角花齿蓟马为害后,R-1根、茎和叶的农艺性状及抗性比I-1好,对同化产物的分配利用率高.     

番茄潜叶蛾幼虫和卵在新疆大棚番茄的空间分布型及理论抽样数

【目的】明确新疆新发外来入侵生物番茄潜叶蛾幼虫和卵在不同种群密度下的垂直分布、空间分布型和理论抽样数,探索田间易观察的危害症状和幼虫密度的关系,为田间取样和调查提供理论指导。【方法】在察布查尔县连续调查3个大棚同一品种京番502杂交一代上的番茄潜叶蛾的不同种群密度,利用聚集度指标及Iwao回归分析,计算并分析了番茄潜叶蛾卵和幼虫在不同种群密度下的空间分布型、垂直分布和理论抽样数,分析危害叶片数、虫道长度和虫道数与幼虫密度的动态关系。【结果】计算并统计番茄潜叶蛾幼虫和卵的空间分布聚集度指标的均值m、扩散系数C、扩散型指数I、负二项分布值K、平均拥挤度m~*、聚块指数m~*/m、扩散指数CA和种群聚集均数λ。番茄潜叶蛾卵主要集中在上部,占比43.9%～100%。幼虫主要集中在下部,占比53.3%～100%。番茄潜叶蛾幼虫数与虫道数、虫道长度或为害叶片数的比值随为害加剧呈动态变化。番茄潜叶蛾幼虫和卵Iwao直线回归方程拟合公式为m~*=1.9114+1.2055m (R~2=0.9703)和m~*=0.0536+1.4147m (R~2=0.9014)。根据空间分布型参数,在D=0.1、0. 2和0. 3时,幼虫的理论抽样数模型分别为n=1118. 4/x+78. 9、n=279. 6/x+19.7、n=124.3/x+8.8,卵的理论抽样数模型分别为n=404.8/x+159.3、n=101.2/x+39.8、n=45.0/x+17.7,该模型适用于不同虫口密度下的田间抽样。【结论】在京番502杂交一代上,番茄潜叶蛾幼虫为m=0.6头·株~(-1)以上,卵在达到密度最大值前,均呈聚集性分布。番茄潜叶蛾成虫偏好在幼嫩的叶片产卵,随植株被害加剧该偏好略有减弱。当番茄潜叶蛾幼虫的虫口密度为10和30头·株~(-1)时,建议分别取样50和30株;当卵量为10和30粒·株~(-1)时,分别取样50和45株。     

华南阔叶树种幼苗叶片的养分特征

研究了阔叶树种幼苗山杜英、红锥、海南红豆、火力楠、红花油茶、枫香、黎蒴、米老排和樟树的N、P、K浓度和单位叶面积含量。结果表明,海南红豆、黎蒴和樟树的N、P、K浓度较高,而红花油茶、黎蒴和樟树的单位叶面积N、P、K含量较高,9种树种的上部和下部叶片的平均养分浓度分别为N16．67和17．09g·kg^-1,P1．29和0．84g·kg^-1,K11．77和6．65g·kg^-1,平均养分含量分别为N0．871和1．069g·m^-2,P0．065和0．052g·m^-2,K0．608和0．426g·m^-2,各树种上部叶片的P和K浓度和含量大于下部叶片,从养分含量的角度考虑,红花油茶与其他8种树种混交,红锥或米老排与山杜英、枫香、海南红豆、黎蒴、樟树混交,火力楠与黎蒴、樟树混交是合理的。     

雷州半岛15个阔叶树种混交幼林的生长分析*

通过15个阔叶树种2.5a生幼林在雷州半岛的生长比较,结果表明,树高、胸径和冠幅生长超过所有树种平均值的有水翁(Cleistocalyx operculatus)、盘架子(Winchia catophyua)、麻楝(Chukrasia tabularis)和秋枫(Bischofia javanica);按生长过程变化15个树种可分为3个类型:一是水翁、盘架子、秋枫和阴香(Cinnamomum burmanni),二是山楝(Aphanamixis polystachya)、麻楝、樟树(Cinnamomum camphora)、黎蒴栲(Castanopsis fissa)、火力楠(Michelia macdurei)、人面子(Dracontomelon duperreanum)、扁桃(Mangifera persiciformis)和榄仁树(Temninalia catappa),三是见血封喉(Antiaris toxicaria)、木棉(Bombax malabaricum)和无忧树(Saraca dives),不同类型的树种对生态位有不同要求,营造混交林应注意选择搭配。月平均温度、降雨量和相对湿度与多数种类的早期树高生长量与有较好的相关性,而与胸径和冠幅生长量的相关性则不明显。     

Progression of ash canopy thinning and dieback outward from the initial infestation of emerald ash borer (Coleoptera: Buprestidae) in southeastern Michigan

Our objective was to characterize the rate at which ash (Fraxinus spp.) trees decline in areas adjacent to the leading edge of visible ash canopy thinning due to emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). Trees in southeastern Michigan were surveyed from 2003 to 2006 for canopy thinning and dieback by comparing survey trees with a set of 11 standard photographs. Freeways stemming from Detroit in all directions were used as survey transects. Between 750 and 1,100 trees were surveyed each year. A rapid method of sampling populations of emerald ash borer was developed by counting emerald ash borer emergence holes with binoculars and then felling trees to validate binocular counts. Approximately 25% of the trees surveyed for canopy thinning in 2005 and 2006 also were sampled for emerald ash borer emergence holes using binoculars. Regression analysis indicates that 41-53% of the variation in ash canopy thinning can be explained by the number of emerald ash borer emergence holes per tree. Emerald ash borer emergence holes were found at every site where ash canopy thinning averaged > 40%. In 2003, ash canopy thinning averaged 40% at a distance of 19.3 km from the epicenter of the emerald ash borer infestation in Canton. By 2006, the point at which ash trees averaged 40% canopy thinning had increased to a distance of 51.2 km away from Canton. Therefore, the point at which ash trees averaged 40% canopy thinning, a state of decline clearly visible to the average person, moved outward at a rate of 10.6 km/yr during this period.     

Reproduction of invasive Amur honeysuckle (Lonicera maackii) and the arithmetic of an extermination strategy

Ecological restorations often require removal of invasive species. The abundance of invasives has tended to catalyze research emphasizing removal, not broader understandings, of species mechanisms for persistence in the landscape (e.g. reproductive output and seed dispersal). Asiatic shrub honeysuckles (Lonicera spp.) are pernicious invaders throughout eastern North America. Heavy tree canopy cover apparently reduces growth and reproductive output in Lonicera maackii, which is widespread through the lower Midwestern United States. To help focus control efforts more effectively, we quantified the effect of tree canopy cover on vegetative growth, flowering, and fruit production under three canopy densities. Mean vegetative growth of flowering shoots was not affected by canopy cover. All aspects of sexual reproduction (flower production, fruit set, fruit number, fruit mass, seed number, and seed size) were strongly reduced by moderate shade. Although all individuals modify community and ecosystem properties, a limited number of high light individuals might also provide the greatest proportion of the seeds. Through model simulation of honeysuckle population structure in relation to canopy cover, we argue that it can sometimes be more efficient to initially target reproductive individuals in the high light edge and interior gap environments than to immediately focus on all individuals in the forest interior.     

槟榔林冠穿透雨空间格局的时间稳定性

槟榔林是热带地区广泛种植典型经济林,独特的树冠结构改变了穿透雨的空间格局,但针对穿透雨空间格局的时间稳定性研究很少,影响对穿透雨生态效应的认识与调控。以海南岛槟榔林为研究对象,基于33场降雨数据,研究了穿透雨的空间格局及时间特性,结果显示:(1)槟榔树冠内不同位置穿透雨差异极显著(P0.01),穿透雨率分别为:树干附近(85.6%)、冠幅中央(48.3%)、冠幅边缘(59.8%),穿透雨空间格局表现为向树干附近汇集的特点;不同方位的穿透雨率仅东面显著高于南面(P0.1),表明风向对穿透雨空间格局具有一定影响。(2)槟榔树冠下各位点穿透雨时间变异程度大(65.7%),但槟榔树冠幅中央穿透雨时间稳定性较好(55.6%),而树干旁边和冠幅边缘穿透雨时间稳定性较差(25%、19.4%),各方位穿透雨的时间稳定性相差不大(约1/3)。(3)距树干距离和降雨量影响穿透雨的时间稳定性,距树干不同距离平均叶片倾斜角度的差异是造成穿透雨在时间上不稳定的关键因素,平均叶片倾斜角度与穿透雨时间不稳定程度呈现显著正相关关系(P0.05);穿透雨时间稳定性在中等降雨条件下最差,随着降雨量增加,冠层对穿透雨的"屏蔽效应"减弱,"滴水效应"增加。揭示槟榔植株个体穿透雨的空间格局及时间稳定性,可为认识乔木个体尺度穿透雨时空特征提供参考,也可为解释林地小尺度土壤水分和土壤侵蚀的空间格局及时间动态提供依据。     

Biology and damage traits of emerald ash borer planipennis Fairmaire）in China

Emerald ash borer （Agrilus planipennis Fairmaire） （Coleoptera： Buprestidae） is a major stem borer of ash （Fraxinus spp.）. It is univoltine in Tianjin, while it is semivoltine in Heilongjiang Province, and both univoltine and semivoltine in Changchun, Jilin Province, where the majority is univoltine. The longevity of emerald ash borer adults is 17.2 ± 4.6 days （n = 45）, eggs 9.0 5：1.1 days （n = 103）, univoltine larvae 308 days, semivoltine larvae 673 days, and pupae 61.2 ± 1.6 days （n = 45）. It takes about 100 days from the time larvae bore into the phloem to when they complete the pupal cell. In a 10-year-old velvet ash （Fraxinus velutina Tort.） plantation in Tianjin, emerald ash borer preferred to oviposit on the regions of boles from 50-150 cm above ground, accounting for 76.7% of the total girdling. Girdling on the south side of the tree boles accounted for 43.40% of the total girdling. The emerald ash borer population density is higher at the edge of the plantation compared with the center.     

Reducing the impact of insect herbivory in eucalypt plantations through management of extrinsic influences on tree vigour

In this paper it is argued that concepts developed in ecologically derived insect–plant interaction models can contribute directly to the management of insect herbivory in eucalypt plantations. Common to most species of commercially planted eucalypt is their genetic potential for early rapid growth. Several plant defence theories predict that intrinsically fast growing plants are able to tolerate relatively high levels of herbivory. The risk of this strategy failing increases when plants are exposed to external stressful factors that reduce canopy growth and vigour. Results from a young Eucalyptus camaldulensis plantation stressed by moisture deficit and two young Eucalyptus dunnii plantations, stressed by flooding and weed competition, respectively, are summarized. In all three cases, the stress‐inducing agents reduced canopy growth rates and architecture so that the proportion of leaf tissue damaged by insects increased and the tree’s ability to tolerate this damage decreased. Therefore, alleviating tree stress through improved silvicultural practices or improved site selection techniques may indirectly reduce the impact of insect herbivory. In resource‐limiting environments, an alternative approach may be to plant eucalypt species that although slower growing, are predicted to have better defended foliage. Manipulation of these natural antiherbivore plant strategies are not exclusive of other management approaches, such as the need for routine surveillance of key pest insects or the genetic selection of natural insect resistance and selective chemical control techniques, but should be viewed as an overarching concept for plantation health.     

Local habitat and landscape influence predation of bird nests on afforested Mediterranean cropland

Afforestation programs such as the one promoted by the EU Common Agrarian Policy have contributed to spread tree plantations on former cropland. Nevertheless these afforestations may cause severe damage to open habitat species, especially birds of high conservation value. We investigated predation of artificial bird nests at young tree plantations and at the open farmland habitat adjacent to the tree plantations in central Spain. Predation rates were very high at both tree plantations (95.6%) and open farmland habitat (94.2%) after two and three week exposure. Plantation edge/area ratio and development of the tree canopy decreased predation rates and plantation area and magpie (Pica pica) abundance increased predation rates within tree plantations, which were also affected by land use types around plantations. The area of nearby tree plantations (positive effect), distance to the tree plantation edge (negative effect), and habitat type (mainly attributable to the location of nests in vineyards) explained predation rates at open farmland habitat. We conclude that predation rates on artificial nests were particularly high and rapid at or nearby large plantations, with high numbers of magpies and low tree development, and located in homogenous landscapes dominated by herbaceous crops and pastures with no remnants of semi-natural woody vegetation. Landscape planning should not favour tree plantations as the ones studied here in Mediterranean agricultural areas that are highly valuable for ground-nesting bird species.     

Spatial Patterns of Soil Microbial Communities in a Norway Spruce (Picea abies) Plantation

The phospholipid fatty acid (PLFA) profiles of soil microbial communities were determined in relation to the patterns of tree cover in a mature Norway spruce plantation. Replicate samples of the surface organic layers were taken close to the trunk, at 1 m and at 2 m (under the edge of the canopy) beneath five trees. Samples were analyzed for standard PLFAs to assess the initial composition of the microbial communities. Replicate samples were then incubated under constant or fluctuating moisture conditions for 30 d to test the hypothesis that the patterns of microbial community structure (or its physiological state) might be determined by biophysical conditions under the tree canopies. The PLFA profiles near the trunks and at 2 m were similar, but samples taken 1 m from the bases of the trees contained lower concentrations of polyunsaturated (fungal) and monounsaturated PLFAs, and higher concentrations of saturated PLFAs. These differences in PLFA profiles were maintained during laboratory incubation under a regime of drying and wetting cycles, but there was some evidence of convergence in community structure under constant moisture conditions resulting from significant increases and decreases in specific bacterial PLFA concentrations. There were no effects of either moisture treatment on fungal PLFA concentrations. It is concluded that variation in the soil biophysical environment beneath the tree canopies resulted in the differentiation of spatially defined bacterial communities that were tolerant of moisture stress. The anomaly that differences in community structure were largest at an intermediate position of 1 m between the trunk and below the canopy edge was not explained but may relate to tree root distribution.     

Effects of Severe Tropical Cyclone Larry on rainforest vegetation and understorey microclimate near a road,powerline and stream

Abstract Severe Tropical Cyclone Larry damaged a large swathe of rainforest to the west of Innisfail in north‐eastern Queensland on 20 March 2006. Within the path of the most destructive core of the cyclone were sites previously established along human‐made (powerlines and highways) and natural (streams) linear canopy openings for a study of edge effects on adjacent rainforest plant communities and associated microclimates. Vegetation damage and understorey microclimate parameters were measured 6 months after the passage of Cyclone Larry and compared with results before the cyclone. We examined the spatial patterns of vegetation damage in relation to natural and artificial linear clearing edges and the vegetation structural factors influencing these patterns as well as resulting alterations to microclimate regimes experienced in the rainforest understorey. Vegetation damage was spatially patchy and not elevated near linear clearing edges relative to the forest interior and did not differ between edge types. Vegetation damage was influenced, albeit relatively weakly, by structural traits of individual trees and saplings, especially size (diameter at breast height, d.b.h.) and successional status: tree damage was greater in pioneer species and in larger trees, while sapling damage was greater in canopy tree species than in understorey tree or shrub species. Changes in the understorey microclimate mirrored the degree of damage to vegetation. Where vegetation damage appeared greater, the understorey microclimate was brighter, warmer, drier and windier than below less‐damaged areas of the forest canopy. Overall, understorey light availability, wind speed and the diurnal ranges of air temperature and vapour pressure deficit increased dramatically after Cyclone Larry, while pre‐cyclone edge gradients in light availability were lost and temperature and vapour pressure deficit gradients were reversed.