荔蒲吉松叶蜂生物学特性初步研究

荔蒲吉松叶蜂(GilpinialipuensisXiaoetHuang),属松叶蜂科(Diprionidae)、吉松叶蜂属(Gilpinia)。1997年秋末,浙江省仙居县原杨府乡大路溪滩的大面积马尾松(PinusmassonianaLamb.)林突遭荔蒲吉松叶蜂的猖獗危害,其中约3hm2松林被危害致死。1997—2000年全县发生面积623 3hm2,其中近200hm2严重危害。据查,对荔蒲吉松叶蜂生物学特性的研究报道甚少。为此,自1997年冬开始了对该虫的分布与危害情况的调查,并对其生物学特性及防治方法进行摸索探讨。通过近4a的观察与防治试验,基本搞清了该虫的生物学特性及防治方法,现将有关情况小结如下。1　…     

春尺蠖的发生规律及防治技术

春尺蠖（ＡｐｏｃｈｅｉｍａｃｉｎｅｒａｒｉｕｓＥｒｓｃｈｏｆｆ）１９９４年以来在牡丹江市区大量发生，以幼虫取食刚萌发的芽苞、幼叶及老叶，严重地危害了榆、杨柳、锦鸡树等绿化树种。为了控制该虫的发生和蔓延，对其生物学特性、发生规律及防治技术进行了试验研究，取得了较好的效果，控制了该虫的猖獗及危害。１　试验方法个体发育规律　采用室内饲养观察与室外每日定期观测相结合的方法。室内采用２５ｃｍ×２５ｃｍ×５０ｃｍ铁纱网养虫笼饲养，每个笼内放越冬蛹１００头，３次重复。室外模拟自然状态于枯枝落叶层上设样方１ｍ…     

我国苹果绵蚜发生及防治研究进展

概述了近20年来苹果绵蚜在我国的分布与危害、生物学特性、发生规律及防治研究进展。     

粗腿透翅蛾的初步研究

粗腿透翅蛾以幼虫蛀食药用植物栝楼的茎蔓、根颈及主侧根，受害部位形成肿胀虫瘿，严重时导致整株死亡。该文主要观察研究并报道了透翅蛾的形态特征及生物学特性，并提出防治建议。     

核桃黑斑蚜生物学特性与防治试验

核桃黑斑蚜Chromaphis jugland icola(kaltenbach)是核桃树的主要害虫之一。近年来山西核桃产区由于该虫的大量发生为害,使核桃的产量和品质受到很大影响,为此,我们从1987—1990年对核桃黑斑蚜的生物学特性和防治技术等进行了系统研究。明确了该蚜的发生规律和生活习性。通过药剂筛选试验研究,采用对天敌伤害少,而对蚜虫杀伤力强的杀虫剂,在该蚜发生高峰期前进行施药为主的综合防治措施,在推广应用中收到了明显的防治效果。     

梨黄粉蚜生物学特性的研究

<正> 梨黄粉蚜Aphanostigma jaksuise(Kishida)属同翅目,根瘤蚜科,又名黄粉虫。寄主仅为梨,是一种为害梨树的枝干、果实而不为害叶片的蚜虫。被此蚜为害后的梨果,轻者影响外贸出口,重者失去商品价值。1985年由于梨黄粉蚜的为害使河北省的鸭梨出口信誉受到很大影响。为此,我们于1987—1988年研究了此蚜的生物学特性,为有效防治此虫打下基础。现将研究结果报道如下:     

松大蚜生物学特性及其防治技术

本文就宝鸡市松大蚜所造成的危害情况及该虫的生物学特性与综合防治技术，进行了进一步的调查分析与研究探讨。     

新物种青檀绵叶蚜及其综合防治研究初报

青檀绵叶蚜(Shivaphis Pteroceltis Qiao,Jiang and An,sp.nov.)是2007年5月首次被发现的一个危害青檀(Pteroceltis tatarinowii Maxim)的斑蚜科(Drepanosiphidae)、绵叶蚜属(Shivaphis Das)蚜虫新种。2007年以来对其发生规律和综合防治技术进行了研究。     

棕色天幕毛虫的危害习性及防治方法

棕色天幕毛虫属鳞翅目枯叶蛾科，近年来在安徽省皖南泾县地区严重发生，以幼虫危害枫香树叶。为摸清该虫的发生规律，我们于1995～1996年对该虫生物学特性和防治方法进行了观察和试验研究，现将初步结果报道如下。1分布与危害情况棕色天幕毛虫主要分布于我国江西、浙江、福建、广东、广西、四川省（区）。在安徽的分布尚未见记载，有关该虫的生物学特性及防治研究方面报道甚少。笔者于1995年在小溪林场首次发现该虫危害（尚未成灾），到1996年该虫在任县全区范围内大面积暴发成灾实属罕见。据县森防站1996年调查，全县枫树有虫林率达98％以…     

落叶松球蚜生物学特性及防治试验研究

通过对落叶松球蚜发生为害及生物学特性的研究，得出该虫在小陇山林区以青海云杉和落叶松为寄主，两年完成生活周期。其中，以侨蚜在落叶松上一年５代循环危害，５月上旬是第１代侨蚜的初孵若蚜盛期，是防治的关键时期。试用４０％氧化乐果１５００倍液、５０％敌敌畏１５００倍液喷雾，效果均在９０％以上。     

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.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

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。     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.