日本赤松毛虫质型多角体病毒Dendrolimus Spectabilis CPV对马尾松毛虫的生物测定

应用日本赤松毛虫质型多角体病毒(以下简称JDS-CPV)对马尾松毛虫第一代3龄和5龄幼虫进行了生物测定。结果表明,JDS-CPV对3龄和5龄幼虫的LC_(50)分别为1.6×10~5CPB/ml和3.3×10~5CPB/ml。其回归直线方程分别为Y=2.44+0.49x和Y=1.83+0.57x。对一代3龄虫的LD_(50)为2.1×10~3CPB/ml,回归直线方程为Y=1.72+0.98x。以1×10~8CPB/ml浓度为例的LT_(50),3龄虫为8.5天,5龄虫为13天。证实JDS-CPV对我国马尾松毛虫有较好的毒力。     

马尾松毛虫质型多角体病毒的研究——Ⅰ.病毒的毒力测定

本文对马尾松毛虫质型多角体病毒(D.CPV)防治技术进行研究。室内个体、群体毒力测定表明:病毒包含体为2×10~5—2×10~8CPB/ml,校正死亡率均达82%以上,其浓度间致毒死亡率差异不显著。林间防治试验表明:林间致毒浓度为2×10~6CPB/ml时,校正死亡率70.7%,低于病毒加20%速灭杀丁(1∶2.5万倍液)死亡率88.5%的17.8%。温度平均低于18.4℃,幼虫总死亡率(73.5%—77.2%),温度平均在19—29℃之间的死亡率(82.7%—89.9%),病毒致死率相差不大。     

质型多角体病毒对松毛虫的防治实验

通过质型多角体病毒 (CytoplasmicPolyheddrosisVirus ,简称CPV)感染赤松毛虫的室内试验和林地试验 ,分析研究CPV对松毛虫幼虫、蛹、成虫、卵、子代幼虫的数量不同程度的影响 ,得出了松毛虫质型多角体防治林地松毛虫的可行性和良好的效果 ,为林区有效防治松毛虫提供参考     

质型多角体病毒与Bt混用防治赤松毛虫

质型多角体病毒(CPV)与Bt混用,可迅速降低赤松毛虫幼虫的取食量,提高杀虫效果。与单用CPV相比,处理后第5天幼虫的排粪量约为单用CPV的2/3～1/2,LT50值最大差3.6天,LT90值最大差6.9天。     

松毛虫感染质型多角体病毒中肠病变程度与病毒产量的关系

以日本赤松毛虫病毒在马尾松毛虫上的感染株为毒源喷施松针(浓度为1×10~7PIB/毫升),饲喂山东赤松毛虫5—6龄幼虫。接种12—14天幼虫中肠Ⅰ、Ⅱ类病变率达85.10%,第15天采收病毒较适宜。本次试验喷毒量与收获量之比为1:98.9。这表明以林间老熟幼虫为宿主,采用此法繁殖病毒,可在短期内获大量病毒,适合生产单位自行繁殖应用。     

利用棉铃虫为宿主增殖松毛虫质型多角体病毒

应用细胞质多角体病毒JDS-CPV在日本防治赤松毛虫(Dendrolimus spectabilis)以及在我国台湾省防治马尾松毛虫(D.punctatus)均取得较好的效果。自1983年以来,利用JDS-CPV在我国广东、云南、浙江、安徽等省防治松毛虫,也都具有很好的效果。JDS-CPV的复制,过去主要是利用林间的松毛虫。如何使之成为周期性的连续生产,宿主的供     

中国绿刺蛾质型多角体病毒RNA的提取与鉴定

中国绿刺蛾质型多角体病毒RNA(Ps CPV RNA)用热酚法从提纯的病毒多角体中提取。紫外吸收光谱测定最高和最低吸收值分别在260 nm和230 nm处,经测定其T_m值为805℃.在3％聚丙烯酰胺凝胶中,经电泳CPV RNA可分离得到10条基因片段,各片段大小为0.34×10~6～2.57×10~6,总分子量为14.88×10~6.     

马尾松毛虫质型多角体病毒(D、CPV)混剂的研究

马尾松毛虫质型多角体病毒（D、CPV）混剂的研究结果表明，在3种药剂的9个组合中，以A1B1C1组合防治效果最好，在林间防治中，平均校正虫口下降率达97．3％，比单一使用病毒（浓度为2×107CPB／ml）的平均校正虫口下降率（80％）提高17．3％。     

思茅松毛虫质型多角体病毒的应用

应用思茅松毛虫质型多角体病毒 Dendrolimus kikuchii Cytoplasmic PolyhedrosisVirus(Dk CPV)防治思茅松毛虫 Dendrolimuskikuchii和文山松毛虫 D.punctatus wen-shanensis的实验证明用 Dk CPV粉剂防治 3～ 5龄幼虫效果达 97% ,且具有显著的扩散流行和持续控制效果。     

美国白蛾无公害防治

辽宁省自1979年发生美国白蛾以来就开展了生物(仿生物)药剂防治美国白蛾试验,经过十几年的试验、推广、应用确,定了几种药剂的防治方法。1美国白蛾核型多角体病毒1 1防治方法将美国白蛾2～3龄幼虫喂食喷过美国白蛾核型多角体病毒的树叶进行接毒,接毒后5～7d收取虫尸,盛在暗色瓶内放在冰箱(-4℃)或冻库内(-10℃)保存,或制成粗提纯剂放在冰箱或冷库内保存。第一代防治用头年第二代虫尸提纯剂,5×10PIB mL,第二代防治用当年第一代虫尸稀释液,2×10PIB mL。1 2防治效果从防治效果看出(见表1),2～3龄幼虫的死亡高峰为第8天至第9天,3龄为第1…     

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.