栗瘿绿色长尾小蜂的初步观察

<正>栗瘿绿色长尾小蜂Torymus(synto maspis)SP.(俗称栗瘿长尾小蜂或长尾小蜂),属膜翅目,小蜂总科,长尾小蜂科。是栗瘿蜂的主要天敌。近年来,板栗产区栗瘿蜂发生普遍。为了更好地保护和利用栗瘿长尾小蜂,以控制栗瘿蜂的为害,我们对栗瘿长尾小蜂进行了观察,现将结果初报如下。     

栗瘿蜂与中华长尾小蜂种群数量消长关系研究

栗瘿蜂在一定的区域内呈周期性发生，影响栗瘿蜂发生的主导因素是寄生性天敌的种群数量。中华长尾小蜂是最主要的天敌种群。两者相辅相成，相互制约，它们之比称益害比。人工保护利用中华长尾小蜂防治栗瘿蜂，提高栗园益害比达1：5以上时，可控制栗瘿蜂的大发生。     

栗瘿蜂寄生蜂的研究概述

栗瘿蜂为一种孤雌生殖的瘿峰 ,是危害板栗树的最主要的害虫之一。它有许多天敌 ,尤其是长尾小蜂 ,被认为是有效的生物防治手段。文中介绍了栗瘿蜂天敌的种类 ,其中着重介绍长尾小蜂科的有益长尾小蜂和中华长尾小蜂 ,对它们在形态及生理生化上的区别进行了简要综述。中华长尾小蜂的种群在日本增长缓慢 ,在定殖上有一定难度 ,据报道 ,可能与雌雄性比比较低和本地兼性重寄生蜂的活动有关     

锥栗瘿蜂的分布、危害及寄生蜂调查

【目的】研究锥栗瘿蜂在主要锥栗产区的分布、危害特征及天敌种类,比较近缘种栗瘿蜂的形态特征,为控制其危害提供基础。【方法】于福建、浙江及湖南主要锥栗产区采集瘿蜂虫瘿,调查锥栗瘿蜂及其天敌种类和危害情况。【结果】锥栗瘿蜂虫瘿形态与栗瘿蜂相似,以成虫中胸侧板斜纵刻纹、并胸腹节背板侧隆线等特征可与栗瘿蜂相区分。锥栗瘿蜂分布于福建省周宁县、建瓯市、政和县、寿宁县及浙江省庆元县。多与栗瘿蜂混合发生,混合发生地锥栗瘿蜂羽化成虫的数量比例为0.6%～86.0%。调查地有虫株率100%,锥栗瘿蜂的危害枝率为17.9%～32.9%,每虫瘿内虫室数3个左右。植株的东南西北方位皆可致瘿,于树冠上部形成的虫瘿数显著低于中下部,与栗瘿蜂占据着类似的生态位。调查地锥栗瘿蜂的寄生性天敌种类主要有日本大痣长尾小蜂、栗瘿啮小蜂、栗瘿长尾小蜂、栗瘿旋小蜂及黑褐宽缘广肩小蜂,其中日本大痣长尾小蜂和栗瘿啮小蜂为其优势天敌,对锥栗瘿蜂种群数量起到了明显的自然控制效果。【结论】锥栗瘿蜂分布于福建省周宁县、建瓯市、政和县、寿宁县及浙江省庆元县,在锥栗林与栗瘿蜂占据着类似的生态位。主要寄生性天敌种类为日本大痣长尾小蜂、栗瘿啮小蜂、栗瘿长尾小蜂、栗瘿旋小蜂及黑褐宽缘广肩小蜂。     

栗瘿蜂寄生蜂的初步研究

栗瘿蜂的寄生蜂，在山东有２８种，均为小蜂类，主要种１０种，本文对其识别特征作了简单描述。在这些寄生蜂中，有单食性的也有寡食性的；有初寄生的，也有重寄生的；有在体外寄生的，也有在体内寄生的。其中能对栗瘿蜂种群密度的变动产生影响的优势种只有４－５种，在不同的寄生环境中占有一定的生态位，其寄生总效应是以中华长尾小蜂为核心，主导着栗瘿蜂种群密度的周期性变动。     

栗瘿长尾小蜂初步研究

栗瘿长尾小蜂(Torymus sp.)属长尾小蜂科、长尾小蜂属,是栗瘿蜂幼虫的重要天敌之一。作者在禄劝县板栗生产乡的调查表明,凡是有栗瘿蜂危害的板栗园中,都会找到栗瘿长尾小蜂的踪迹,自然寄生率最高可达80%以上,对栗瘿蜂发生有显著的抑制效果。     

寄生于桉树枝瘿姬小蜂的一种长尾啮小蜂

在广西发现寄生于桉树枝瘿姬小蜂（Leptocybe invasaFisher ＆ La Salle）的长尾啮小蜂属（Aprostocetus sp.）的1种重要寄生性小蜂。对其形态特征进行详细描述,并介绍了其林间寄生和跟踪现象。     

板栗瘿蜂寄生性天敌幼期形态研究

本文用常规及电镜扫描等显微观察方法,系统地研究和描述了板栗瘿蜂的主要寄生蜂(中华长尾小蜂、葛氏长尾小蜂、双刺广肩小蜂、黄褐宽缘广肩小蜂、栗瘿旋小蜂、果瘿刻腹小蜂等)的幼期形态特征。结果表明,它们的卵、老熟幼虫和蛹的形态特征差异明显。老熟幼虫的主要分类特征是:头壳和体表上刚毛着生位置、数量和长短;触角形态;上颚形态和大小;体表结构。卵的主要分类特征是颜色,有无印柄,卵及卵柄长短、卵体形态。利用老熟幼虫的形态特征进行小蜂的类群分类是可行的。     

中国板栗瘿蜂天敌的研究

从中国11个省市,20个县采集到23,878个栗瘿瘤,并从中育出各种寄生蜂3999头,共30种,分属11个科。对其中分布广、数量多的中华长尾小蜂Torymussinensis Kamijo,葛氏长尾小蜂T.geranii(Walker),玫瑰广肩小蜂Eurytomarosae Nees,黄褐宽缘广肩小蜂Decatoma concinna(Boh.),黑褐宽缘广肩小蜂D.variegate(Curtis),纵脊刻腹小蜂Ormyrus Punctiger var.rulifanusMayr,栗瘿旋小蜂Eupelmus urozonus Dal marl,栗瘿姬小蜂 Tetrastichussp.等进行了较深入的研究。并且通过虫瘿解剖及幼虫形态鉴别确认了它们之间的、以及它们与栗瘿蜂之间的关系。研究表明,栗瘿蜂天敌在栗瘿蜂种群动态自然调节中起重要作用。     

灌根法防治栗瘿蜂试验初报

栗瘿蜂是危害板栗等的重要害虫之一。本试验通过用内吸性杀虫剂灌根防治栗瘿蜂,结果表明:在栗瘿蜂幼虫期用50％甲胺磷乳油150倍液每株5公斤灌根,死虫率达66.82％,校正杀虫率为64.82％,同时兼治粟大蚜等害虫。此法优于栗瘿蜂成虫出瘿期喷药防治。     

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.