沙棘主要蛀干害虫研究概述

沙棘木蠹蛾和红缘天牛是沙棘的两种主要蛀干害虫,主要以幼虫危害沙棘的根部和干部。沙棘木蠹蛾近年在沙棘种植区大面积暴发,红缘天牛也多伴随发生。目前,从生物生态学特性、成灾原因、监测和防治措施等方面,对这两种害虫的研究已取得了很大的进展。本文对沙棘木蠹蛾和红缘天牛不同发生地的生活史、危害特性、暴发成灾的主要原因及所采取的主要防治方法进行概述,以期能进一步更有效地促进其危害控制的研究和应用。     

沙棘木蠹蛾在辽宁省发生危害原因及对策

沙棘木蠹蛾(Holcocerus hippophaecolus)属鳞翅目、木蠹蛾科,1986年在辽宁省首次发现,2001年起,沙棘木蠹蛾在辽宁省西部暴发成灾,致使沙棘林出现大面积死亡现象。并呈继续扩散蔓延趋势,已造成了巨大的经济损失。1沙棘木蠹蛾的发生与危害状况沙棘木蠹蛾在辽宁省主要发生在朝阳市建平县、北票市;阜新市的阜新县、彰武县。根据实地调查测定,朝阳地区所有沙棘林均受到沙棘木蠹蛾的危害,多数林分沙棘个体死亡率达50%以上,有虫株率80%以上,虫口密度20头以上。2沙棘木蠹蛾发生危害的原因分析2.1沙棘木蠹蛾的生物学特性沙棘木蠹蛾4年1代,以幼虫在被…     

辽宁省沙棘木蠹蛾综合治理初步研究

沙棘木蠹蛾Holcocerus hippophaecolus Hua,Chou,Fang et Chen是沙棘的一种钻蛀性害虫,主要在寄主主干和根茎内蛀食危害。近年来,在辽宁、内蒙古、山西、陕西等地发生大面积危害,并呈加剧之势。作者详细调查了沙棘木蠹蛾在辽宁的危害,开展了化学防治试验和沙棘林分大面积营林改造等综合治理措施的研究。研究结果表明:沙棘木蠹蛾的危害与林龄成正比,林龄愈大危害愈重;纯林和混交林中的沙棘受害程度无明显差别;采用营林改造技术林分生态系统恢复快,效果明显,中度受害的林分平茬更新当年即可丛生枝条,2 a即可成林,是控制沙棘木蠹蛾的有效方法。     

当前沙棘木蠹蛾研究中存在的主要问题

沙棘木蠹蛾的大面积暴发,使得其控制研究取得了前所未有的进展,从基础性研究到多种控制方法的实施,都在一定程度上控制了沙棘木蠹蛾的进一步发生和危害。然而,在研究过程中,也出现了许多分歧和问题。为此,本文对沙棘木蠹蛾的研究现状、研究中所存在的问题以及控制技术等方面进行了详细的研究和探讨,以期为沙棘木蠹蛾的综合控制提供较好的理论依据,同时为更有效地控制其危害提供理论指导。     

沙棘木蠹蛾防治技术

沙棘木蠹蛾是危害沙棘的主要蛀干害虫。对沙棘木蠹蛾危害特性、危害程度进行了调查并对防治方法进行阐述,以期能更好地了解沙棘木蠹蛾及其危害,进一步研究出更有效的防治方法。     

基于文献计量学的钻蛀性害虫沙棘木蠹蛾的研究动态分析

沙棘木蠹蛾(Holcocerus hippophaecolus Hua,Chou,Fang et Chen)以幼虫钻蛀危害沙棘的根部、干部,使其大部分被蛀空,导致沙棘大面积死亡,已严重影响到沙棘产业的发展.笔者以中国知网数据库所收录的期刊论文、硕博论文、会议论文、成果和专利5类文献作为统计对象,针对"沙棘木蠹蛾"研究文...     

林木新害虫沙棘木蠹蛾的控制策略

该文对我国沙棘木蠹蛾的发生现状和主要成灾原因进行了简要评述，指出沙棘木蠹蛾已成为制约沙棘事业发展的主要因素之一。立地条件差、树种或品种单一、对该害虫生物生态学特性了解很少以及监测技术缺乏是沙棘木蠹蛾大发生的主要原因。控制策略是在系统进行生物生态学特性研究的基础上，开发性引诱剂和环境协调性药剂应用技术，保护和利用天敌资源，开展沙棘抗旱抗虫品系选育，转变营林模式，最终建立起有效控制沙棘木蠹蛾灾害的综合技术体系。     

内蒙古沙棘木蠹蛾风险分析

沙棘木蠹蛾是以危害沙棘为主的一种钻蛀性害虫，是我国公布的第一批林业危险性有害生物之一。从在内蒙古的分布状况、潜在的危险性、寄主植物的经济重要性、传播扩散的可能性和危险性管理难度等方面对沙棘木蠹蛾进行了风险分析，结果表明沙棘木蠹蛾在内蒙古自治区属高度危险性有害生物，对内蒙古的生态系统、水土保持及农林经济具有一定的危险性，须采取有效措施控制其危害和扩散。     

中国木蠹蛾研究进展情况

木蠹蛾是危害林木和果树的重要害虫。记载我国木蠹蛾的文献可以远溯到二百多年以前,近二、三十年大面积发生成灾。国内对该类害虫进行研究,始于70年代,80年代得到了较大的发展。国内对大面积发生成灾的11种木蠹蛾的生物学及防治技术进行了详细的研究,发表有关论文共63篇,仅80年代即发表39篇。中国木蠹蛾分类工作的开展,是在西北农业大学周尧教授主持与指导下进行的,我们与其合作,完成了《中国木蠹蛾志》一书的编著出版,该书包括我国木蠹蛾两亚科,13属,61种,其中有11个新种(成书前还发表过5个新种)。在防治技术方面的研究,由过去单一的化学药剂防治,发展为营林措施防治、生物防治、人工合成性诱剂使用及大面积的综合防治措施。在生物防治方面,白僵菌剂的使用,取得大面积的防治效果。人工合成性诱剂在较大范围内的试验,也获得初步成效。在大面积范围内采用综合防治措施,也取得令人满意的结果。     

沙棘木蠹蛾性诱剂在林间监测中的应用

为了解右玉沙棘木蠹蛾成虫种群动态变化现状,利用沙棘木蠹蛾性诱剂在林间开展监测试验,并与2006年至2009年间的监测数据相比。结果表明,2006年至2009年沙棘木蠹蛾发生程度大幅度上升,而到2019年沙棘木蠹蛾的发生程度明显降低。沙棘木蠹蛾性诱剂在林间的监测和诱集效果明显,优势突出,具有推广价值。     

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.