本土寄生蜂防治松突圆蚧技术

松突圆蚧是严重为害马尾松的外来有害生物,文章介绍了应用本土寄生蜂防治松突圆蚧技术,包括本土寄生蜂的主要种类、种源调查与保护、放蜂方法和放蜂量、放蜂林分选择、效果检查等。     

松突圆蚧本土寄生蜂的研究

我国利用松突圆蚧(Hemiberlesia pitysophila)寄生蜂已经20多年,但除了占比例很少的试验点外,均未达到控制松突圆蚧成灾、扩散、蔓延、恢复林木长势的目的.为了系统的了解松突圆蚧寄生蜂的应用情况,本文对本土寄生蜂防治松突圆蚧的研究成果进行了归纳和总结,以期全面的认识本土寄生蜂防治松突圆蚧的实际情况.     

寄生蜂防治松突圆蚧的研究进展

文章介绍了松突圆蚧（Hem iberlesia pitysophilaTakagi）的发生历史、危害及防治现状。从生物防治上分别介绍了松突圆蚧寄生蜂花角蚜小蜂（引进种）的生活习性、对松突圆蚧的控制效能、近年来广东花角蚜小蜂种群数量下降的原因等研究进展,以及应用本地寄生蜂防治松突圆蚧的进展情况,并从林间生态位的角度介绍了松突圆蚧及其3种寄生蜂的相互关系。最后讨论了应用寄生蜂防治松突圆蚧过程中存在的问题,提出了相关建议。     

花角蚜小蜂防治松突圆蚧技术的应用

应用花角蚜小蜂防治松突圆蚧面积达１００多万ｈｍ＾２,全面覆盖松突圆蚧疫区范围。放蜂定居成功率达８５％以上,花角蚜小蜂普遍形成自然种群,有效地减缓松突圆蚧的扩散速度及将松突圆蚧控制在有虫不成灾的范围。     

寄生蜂花角蚜小蜂防治松突圆蚧的研究

花角蚜小蜂(Coccobius azumai)属蚜小蜂,是日本松突圆蚧上的优势种天敌.有关资料表明[1],在松突圆蚧原发生地日本冲绳,由于花角蚜小蜂的寄生控制,松突圆蚧对松树危害并不严重.因此,1986年我国从日本首次引入了花角蚜小蜂,并进行了大量的研究与应用试验.本文综述了自1999年以来的寄生蜂花角蚜小蜂防治松突圆蚧(Hemiberlesia pitysophila)的研究,以便更系统了解寄生蜂防治松突圆蚧的情况.     

应用花角蚜小蜂防治松突圆蚧的试验

利用日本花角蚜小蜂防治松突圆蚧，１９８９年林间释放定居成功，１９９０～１９９３年采用人工挂放和飞机撒放种蜂枝条的方法，防治控制面积１４．０９万ｈｍ２。放蜂点的小蜂定居率达９８％以上，１．５年后，松突圆蚧雌蚧被寄生率稳定在２０％～３０％，雌蚧密度由放蜂前每针束３头以上，下降为每针束０．３～０．６头，防治效果显著。     

花角蚜小蜂防治松突圆蚧技术的应用

应用花角蚜小蜂（ＣｏｃｃｏｂｉｕｓａｚｕｍａｉＴａｃｈｉｋａｗａ）防治松突圆蚧（ＨｅｍｉｂｅｒｌｅｓｉａｐｉｔｙｓｏｐｈｉｌａＴａｋａｇｉ）面积达１００多万ｈｍ２，全面覆盖松突圆蚧疫区范围。放蜂定居成功率达８５％以上，花角蚜小蜂普遍形成自然种群，有效地减缓松突圆蚧的扩散速度及将松突圆蚧控制在有虫不成灾的范围。     

松突圆蚧花角蚜小蜂引进和利用的研究

本文介绍了从日本冲绳输引松突圆蚧花角蚜小蜂Coccobius azumai Tachikawa到我国广东省防治松突圆蚧Hemiberlesia pitysophila Takagi的研究。通过对该蜂的繁育、释放及其对松突圆蚧的控制效能等研究,采用松突圆蚧密度较大的小片林地繁育种蜂,再用蜂源地的种蜂枝条扎成2—3kg一把,以600m的间隔进行人工挂放或飞机撒放的方法,放蜂面积约26万公顷,结果表明:95%以上的放蜂点定居成功,放蜂后一年内平均寄生率40%以上,二年后松突圆蚧雌蚧密度控制在每针束1头以下,虫口下降80%—90%,起到了较好的控制作用。     

真菌防治松突圆蚧的试验和应用

发现自然寄生于松突圆蚧的真菌并研制出生防菌.利用菌液对不同类型马尾松上松突圆蚧的防治试验,松突圆蚧的菌粉林间维持和大面积应用效果.生防菌是有效控制松突圆蚧的微生物,值得推广应用.     

松突圆蚧花角蚜小蜂种群下降原因初析

198 9年广东省从日本引进花角蚜小蜂成功控制了检疫性害虫松突圆蚧灾情。 1998年后放蜂区花角蚜小蜂种群急剧下降、数量大幅度减少 ,后因小蜂种源缺乏放蜂工作中断 ,致使松突圆蚧虫口密度逐渐上升 ,灾害日益严重。本文结合花角蚜小蜂的生物学特性及影响花角蚜小蜂种群稳定的因素 ,从气温、寄主、种源 3个方面初步探讨广东松突圆蚧花角蚜小蜂种群下降的原因     

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.