两种毒蛾核型多角体病毒病的初步观察

1976年从以来,我们对舞毒蛾(Ocneria dispar L.)和苹毒蛾(DasychiraPudibunda L.)的两种核型多角体病毒病进行了初步的观察。两虫均属鳞翅目,毒蛾科。食性很杂,是重要的园林树木害虫。舞毒蛾广泛分布于我国各地。苹毒蛾主要分布于我国华北、东北等地区。在沈阳市这两种害虫均普遍发生,其中尤以舞毒蛾为害较重。去秋我们首先在公园、苗圃的林地内,发现苹毒蛾老龄幼虫大量死亡。又于今年4月下旬,发现在室内饲养的3—4龄舞毒蛾幼虫大量死亡。发病幼虫,虫体均呈现痈肿、色亮,表现迟钝,不取食。其死亡形态,苹毒蛾幼虫多爬到树冠的上半部,以腹足附着于枝条或叶片上,呈倒“V”字型悬挂,或以尾足附着于枝、叶上倒挂。舞毒蛾在室内饲养的条件下,幼虫也以腹足或尾足附着于饲养箱壁或枝、叶上呈倒“V”字型或倒挂死亡。死亡后的幼虫,体节拉长,体色逐渐变深,体壁极易破裂,流出淡黄或浓稠     

贵州省1990年防治松毒蛾效果检查评比报告

1松毒蛾为害概况松毒蛾是我省近年来发生面积大、为害地点分散、扩展蔓延迅速.造成经济损失严重的一大森林害虫。据普查材料统计,松毒蛾仅分布于天柱、三穗、石阡、松桃、修文等县,曾于1976年在天柱小面积发生。迄今该虫的分布范围已涉及贵阳、惠水、龙里、余庆、麻江、万山、独山等县(市)。1987年,松毒蛾首次在罗甸县国营林场马尾松林内大面积暴发,有虫     

黄羽毒蛾观察初报

黄羽毒蛾Pida strigipennis(Moore),别名细纹黄毒蛾,属鳞翅目毒蛾科。有关该虫的生物学特性、寄主,国内未曾见报道。1983年在森林昆虫调查中,发现该虫在我县为害多种林木,且分布广泛。为了进行防治,近年来对该虫做了观察,现将结果整理如下,供参考。     

舞毒蛾核型多角体病毒的初步研究

舞毒蛾Lymantria dispar(L.)为林业重要害虫之一,食性杂,危害树木达数十种之多,如杨、柳、栎、松、杉等。该虫在欧洲、北美及亚洲均有分布。国内分布于东北、河北、江苏、台湾、四川、辽宁等地。在大兴安岭主要危害柞、山杨、落叶松。 1976年在辽宁省盖县杨树林舞毒蛾大发生区,我们经过镜检,发现患病致死的大量幼虫为病毒所致。舞毒蛾核型多角体病毒病广泛发生于美国、欧洲,在德国的部分地方也有发生。最初称作树顶病Smith,K.M.(1976)。Rollinson,W.D.et al,(1965)试验证明,将多角体喷于舞毒蛾取食的植物上,能引起舞毒蛾病害的流行。国内关于舞毒蛾核型     

侧柏毒蛾生活规律观察及防治试验

侧柏毒蛾Parocneria furra(Leech)属鱗翅目,毒蛾科,柏毒蛾属。据资料记载,该虫在我国分布于河北、江苏、浙江、四川、湖南、湖北、山东、河南、青海、广西等省。主要为害侧柏、黄桧、桧柏、臭柏[Sabina vulgrais Antoine (Juniperus sabina Linn.)]等。我县大保当、瑶镇公社的臭柏林亦受害严重,林木的嫩枝、     

杨毒蛾生活习性研究初报

杨毒蛾(Leucoma SalicisL.)属鳞翅目毒蛾科。国外分布于朝鲜、日本、蒙古、苏联美国等地。国内分布于黑龙江、山东、山西、辽宁、吉林、新疆、青海、宁夏、甘肃、陕西、西藏等省(区)。我区一些盟市均有发生,乌盟较多,尤以商都、化德、察右后旗、察右前旗、兴和、丰镇、凉城等地受害严重。主要危害杨、柳树。几年来,杨毒蛾在察右前旗连年发生,危害猖獗,大发生时成片的林子树叶被吃光,造成植株干枯,树木生长受到很大影响。其发生特点是:突然暴发,来势凶猛,面积较大,被害严重。为了摸清规     

午毒蛾的卵寄生蜂——平腹小蜂

在午毒蛾的寄生物中有些特别引人注意的寄生在卵期能将其消灭在开始为害以前的种类。可以有把握的说,其中最有实践意义的是平腹小蜂Anastatus disp-aris。它广泛分布于俄罗斯的草原地带,乌克兰、克里木、乌兹别克斯坦、吉尔吉斯、巴萨基尼亚和远东(大陆部分),在很多欧洲国家、日本和美国也有发现。在最适宜的条件下平腹小蜂能感染60—100％的午毒蛾卵块;而在个别的卵块的卵粒寄生率达68.5％。     

回归分析方法在检验松毒蛾越冬蛹空间分布型与抽样调查中的应用

本文采用测定空间分布型的回归分析方法:Iwao的m-m模型,徐汝梅、于秀林、马占山改进的m-m模型,Taylor的幂法则和兰星平的m-v模型,对省龙里林场松毒蛾越冬蛹的空间分布型进行了检验。确定了不同模型下的序贯抽样方程,最适抽样数量的方程。检验结果表明松毒蛾越冬蛹的空间分布型为聚集分布,分布的基本成分为个体群。     

洁泰毒蛾生物学特性

洁泰毒蛾生物学特性王家双，陈宝泉，董彦才，栾风福（莒南县林业局，２７６６００）洁泰毒蛾ＴｅｉａｉｍｍａｃｕｌａｔａＧａｅｄｅ，属鳞翅目毒蛾科，省内已知分布于莒南、临沭等地，寄主为条编柳类（杞柳、筐柳、簸箕柳等）、山枣子（小灌木）、胡枝子及农作物花生。...     

法国梧桐茸毒蛾的初步观察

茸毒蛾[Dasychira pudibunda(Linnaeus)],别名苹叶纵纹毒蛾,苹毒蛾,属鳞翅目毒蛾科茸毒蛾属。 此虫于一九八○年秋,在我县临天桥一带人行道及庭园内法国梧桐树上猖獗一时。每株树上少则几百条,多则数千条。仅在八、     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.