竹巨股长蝽生物学特性初步研究

竹巨股长蝽Macropes bambusiphilus Zheng在浙江省一年1代，以成虫在竹林地表落叶下越冬。越冬成虫3月底至4月初上竹，5月中旬开始产卵，下旬出现若虫，若虫5龄，历期约1个月，6月底出现当年成虫。成、若虫主要生活在小枝竹箨、竹花竹箨及竹小峰危害产生的虫苞叶鞘中。     

草履蚧的发生与防治

草履蚧每年1代,1月下旬越冬,卵在0℃以上就可孵化.初龄若虫2月中旬上树后,定居在1年生枝条上芽眼旁、叶痕处或1～2年生枝条交界处吸取树液危害.2龄若虫4月上旬出现,3龄若虫4月中旬出现.4月底雌雄成虫交尾后,雄虫死去,雌虫减少取食,下树潜入土中或老树皮产卵30～50粒,以卵越冬.不同时期的防治措施如下:     

淡娇异蝽生物学特性及无公害防治

对武义县板栗林中为害较为严重的淡娇异蝽30多年的观察和防治试验表明,淡娇异蝽1年1代,以卵越冬,越冬卵一般在2月下旬至3月上旬孵化,4月上中旬若虫开始为害嫩梢,5月中旬至6月上旬陆续进入成虫期,10月底或11月初开始产卵越冬;若虫发育历期34～61 d,3龄若虫对板栗危害最严重;成虫历期145～213 d;卵期102～135 d;无公害防治采取刮除卵块,石硫合剂喷雾,2.5%的溴氰菊酯、10%吡虫啉防治淡娇异蝽药效最好。     

防治竹卵圆蝽的策略及方法

<正> 竹卵圆蝽是近年来在毛竹上新发现的重要害虫,浙江省1984年被害毛竹林面积仅1万余亩;1987年湖州市、杭州市的5个县及1个区已有18.6万亩毛竹林被害。严重被害毛竹林竹株枯死率高达75%,急需防治的占被害竹林面积的50%以上。在什么时间,用什么方法防治此虫,最为安全、经济、有效,是迫待解决的问题。笔者根据近几年来的研究及防治试验结果,谈谈此虫的防治策略及防治方法,供生产单位参考。一、竹卵圆蝽生活史简介竹卵圆蝽为一年发生1代,以3、4龄若虫于地面枯枝落叶下越冬(4龄占98%),翌年4月中旬爬行上竹,在竹枝、干的节上取     

竹卵圆蝽生物学特性及其天敌种类调查研究

通过调研，基本摸清了竹卵圆蝽的生物学特性和天敌种类。该虫在湖南省1年发生1代，3月中旬，越冬若虫爬行上竹群集竹秆、竹枝取食毛竹汁液；5月中旬羽化成虫；6月中下旬开始交尾产卵；11月中旬以2～4龄若虫下至地面笋壳、枯枝落叶层下越冬。该虫天敌种类较多，其中卵期有5种寄生蜂。     

竹卵圆蝽的生物学及其防治

竹卵圆蝽Hippota dorsalis(Stal)属半翅目、蝽科。是近年来在浙江西北部竹林中暴发的一种重要害虫。据安吉县1987年调查,受害竹林面积已达8.1万亩。该虫在浙江安吉为一年一代,于11月以4龄若虫在地表落叶层下越冬,翌年4月上中旬开始取食为害,若虫5龄,除越冬外,若虫常年在竹上为害。用黄油、机油、溴氰菊酯混合剂在竹秆基涂环可阻止若虫上竹,在秆基注射50％甲胺磷乳剂,虫口减退率达90％以上。     

榉树枝毡蚧在上海的生物学特性及发生规律

榉树枝毡蚧Eriococcus abeliceae Kuwana在上海部分地区首次发生,严重危害榉树Zelkova serrata的健康生长。为有效控制虫害发生,通过野外调查和室内饲养相结合的方式研究了该虫的生物学特性及发生规律等,结果表明:榉树枝毡蚧在上海地区1 a发生1代,以2龄雌若虫及雄蛹越冬。3月上旬始见雄成虫,3月中下旬为羽化高峰期。5月上旬受精的雌成虫开始孕卵,5月中旬达到产卵盛期,每雌平均产卵265粒。6月上旬卵开始孵化,6月中旬至下旬达到孵化盛期,但孵化不整齐,可持续到7月初。8月底第1次蜕皮进入2龄,9月底雄若虫蜕皮变成预蛹,7~8 d后进入蛹期,10月下旬进入越冬状态。     

东方绛蚧生物学及防治研究

东方绛蚧ＫｅｒｍｅｓｏｒｉｅｎｔａｌｉｓＳｈｉｅｔＬｉｕ一年１代，１０月中、下旬以２龄若虫在芽基、枝干裂缝等部位越冬。第二年３月下旬开始为害，雌若虫在原处脱皮２次进入成虫期，雄若虫转移到枝干或地面杂草处作茧，经预蛹和蛹期，５月上旬羽化为成虫，５月下旬是雌成虫产卵和卵孵化高峰。１龄若虫初期是化学药剂防治的有利时机     

竹蝉生物学特性的研究

竹蝉在浙江省为6a1代，若虫于地下吸食竹子鞭、根的汁液以卵在竹上枯枝中和各龄若虫在土下越冬，成虫发生在6月底，7月初到9月上中旬，刺吸竹、树树汁液为补充营养，有扑灯、鸣叫习性；7－8月在竹上已死2－3年的枯竹枝上产卵，每产卵孔中有卵12－21粒，卵于下年7月上旬孵化。若虫5龄，生活于土下5－40cm深的竹鞭两侧，每穴1虫，虫穴与地面有垂直的通气孔；若虫性好斗，两虫相遇，常争斗致伤或致死。天敌较多，重要的有竹蝉卵旋小蜂，38．3％－41．4％的产卵孔中发现有旋小蜂的幼蜂，1头幼蜂可食竹蝉卵2－4粒。竹蝉履甲取食若虫，挖掘500余头老熟若虫于室内饲养，若虫被食率28．71％－32．58％。蝉花菌也寄生若虫，经5a调查，寄生率为32．5％－37．8％。防治竹蝉可采取加强竹林管理、挂枝诱成虫产卵、灯诱成虫及人工捕捉等措施。     

竹卵圆蝽生活史及防治

1.竹卵圆蝽(竹蝽象)生活习性竹卵圆蝽(竹蝽象)是半翅目,蝽科,渐变态害虫,一年一代。以中龄幼虫在地表渣石或石块下越冬,3月惊蛰后开始上竹,但不整齐。阳坡上竹早,阴坡较晚,上竹后群集取食,每节处少则3￣5只,多则10只以上,取食处竹节流汁,刚上竹的若虫便于人工药杀。4￣7月取食最为活跃(对竹子的危害也最严重)。成虫体长12￣16毫米,扁平,黑褐色或灰白色,中胸小盾片发达,口器刺吸式,腹部有臭腺。成虫6￣8月交尾,交尾后10天左右产卵,卵产于竹上部枝叶上。每卵块7￣18粒。卵粒长圆形,长约0.8￣1毫米。初产卵粒米黄色,快孵化时黑褐色。卵粒排列紧密,纵向成行,错位排列。卵产后7天左右孵化,初孵幼虫淡红色,在竹上部活动,逐渐长大为黄褐色,长到6毫米(荞壳大小)长时,变为黑褐色(背部三角盾已明显),11月初下到地面越冬(向阳山坡11月中下旬还有幼虫在竹上取食)。2.竹卵圆蝽的伴生害虫——小蚂蚁竹卵圆蝽危害的竹林,小蚂蚁特别多,约是竹卵圆蝽的10倍以上。蚂蚁本身不能破坏毛竹的输导组织,但竹卵圆蝽吸食竹子后,使竹子流汁招来蚂蚁取食。它们集中在竹卵圆蝽危害过的竹节枝丫处、流汁处进行取食,每盘枝节处都有一堆小蚂蚁,它们和竹...     

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.     

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.     

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.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

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.     

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。