桉树扦插苗主要病虫害及其防治技术

从桉树扦插育苗过程中可能发生危害的主要病害和主要虫害的种类和防治方面展开论述,总结了灰霉病、茎腐病、叶斑病以及桉小卷叶蛾、蚜虫、小地老虎以及白蚁等桉树苗主要病虫害的发生特点、规律和防治方法,对于指导桉树育苗生产有一定的实际意义.     

果树褐腐病的防治技术

褐腐病主要危害苹果、梨、桃、杏、李及樱桃等果树的果实。在8—9月份喷50％甲基托布津可湿性粉剂800×10^-6等可有效预防褐腐病的发生;在果树落花后10d左右至采收前1个月,每隔半月左右喷1次50％多菌灵可湿性粉剂800×10^-6～1000×10^-6等可有效防治褐腐病。     

桉树主要病虫害及防治措施

桉树主要病虫害有:1、溃疡病。危害期多从3月份开始,8、9月份为发病盛期,11月后停止蔓延。防治措施:建立无病苗圃,对病苗彻底清除,加强水肥管理,在病害流行期,适当施磷钾肥,少施N肥。在发病期间可用1:1:100波尔多液或50％多菌灵可湿性粉剂1000倍喷雾防治。2、茎腐病:主要危害苗木。苗木过密,连绵阴雨、高温高湿天气较易发生。通常在桉苗离     

反季节杏树栽培褐腐病的防治技术研究

通过研究用3种药剂喷施处理已发病的杏树反季节杏树栽培褐腐病的防治技术,结果表明,棚室内反季节栽培杏树一旦发生褐腐病,应立即喷施80%代森锰锌可湿性粉剂0.125%药液,每隔7d喷1次,连喷3次。     

我省当前桉树的主要病害问题

文中对我省当前新发现的桉树的主要病害:桉树青枯病、按树间座壳菌溃疡病及桉树扦插苗柱枝菌叶枯病和菜豆壳球抱菌茎腐病的病源、病原菌、症状作了阐述,并提出了防治方法.     

噻虫啉防治花椒蚜虫和红黄蜘蛛药效试验

噻虫啉防治花椒蚜虫和红黄蜘蛛药效试验表明,2%噻虫啉可湿性粉剂速效性较好,有效期在10 d左右;3%噻虫啉悬浮剂持效性较好,持效期20 d左右。2%噻虫啉可湿性粉剂1 000倍液防治效果优于2%噻虫啉可湿性粉剂1 500倍液,3%噻虫啉悬浮剂500倍液防治效果优于3%噻虫啉悬浮剂1 000倍液。     

银杏幼苗茎腐病的诊断与防治

银杏幼苗茎腐病的诊断与防治○朱少云银杏茎腐病又叫苗枯病，夏季高温多湿地区发病严重。该病对播种苗、扦插苗、一年生移栽苗均有很大程度的危害。如何诊断与防治，应引起广大育苗工作者的高度重视。一、诊断一年生苗的初期症状是茎基部变成褐色，叶片失去正常绿色，稍向...     

桉树无性扦插苗病害的发生与防治研究

近年来桉树作为造纸和纤维板原料显出其特殊和重要。六万林场计划在近几年内种植桉树５万亩 ,在种苗供应上主要采取无性扦插培育。但在培育苗木过程中 ,苗木大量死亡 ,给育苗承包者带来极大的难题。笔者为此对扦插苗的病害种类及危害程度进行了调查研究 ,并对各主要病害的发生规律进行了观察与防治试验 ,现总结如下 :主要病害的发生规律与防治１．穗腐病发生情况 :主要危害扦插后７～３０日的苗木 ,危害率一般为２０ %左右 ,有的高达５０ %～７０%。症状与发生特点 :表现为苗木的下部分叶及茎基变褐色 ,叶片失去正常绿叶 ,稍向下垂 ,随之受…     

速生桉五种重大病害及其防治

从发生情况、危害程度、病原、症状及防治方法介绍了严重危害桉树的灰腐病、焦枯病、青枯病、茎腐病、红叶枯梢病等5种病害。     

几种生根剂对桉树扦插育苗作用的试验初报

用双吉尔-GGR6号、CPD生根粉、2%萘乙.吲丁可溶性粉剂、20%α-萘乙酸粉剂等4种生根剂分别处理桉树插穗进行扦插育苗试验,结果表明:不同生根剂对扦插苗生根率、苗高、地径的影响差异达到极显著水平,不同处理间扦插苗生根数有显著差异,而扦插苗的根长差异不显著。用双吉尔-GGR6号和CPD生根粉处理的扦插苗以上5项指标均比用2%萘乙.吲丁可溶性粉剂和20%α-萘乙酸粉剂处理的明显提高。     

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.