黄刺蛾的生活习性及防治技术

黄刺蛾在通化地区1a1代，以幼虫在为害树的枝叉处结茧越冬，是园林植物的主要食叶害虫之一。可采用秋冬季节人工摘除虫茧或敲碎树干上的虫茧，用黑光灯诱杀成虫，幼虫期喷施每克含孢子100亿以上的青虫菌600倍，喷施80％敌敌畏乳油1000—1200倍液或50％杀螟松、50％辛硫磷乳油1000—1500倍液、50％马拉硫磷乳油1000倍液、25％亚胺硫磷乳油1300倍液、5％来福灵乳油3000倍液、2．5％氯氰菊酯乳油2000，3000倍液等方法进行防治。     

防治松材线虫病的室内药剂筛选

采用40％克线磷乳油、3％克百威颗粒剂、35％阿维菌素乳油及4．5％高效氯氰菊酯乳油4种药剂，分别以6种浓度梯度对松材线虫进行室内药剂生测，初步筛选出防效较好的药剂为40％克线磷乳油，其最佳的使用浓度为200mg／L。     

枣树害虫化学防治

对枣飞象、枣尺蠖、枣镰翅小卷蛾进行林间化学防治,结果表明,5％氯氰菊酯乳油、5％来福灵乳油、20％速灭杀丁乳油、2.5％敌杀死乳油、40％久效磷乳油等可供生产上应用,其浓度随害虫种类的不同而有变化。40％久效磷分别与上述几种农药混用,效果优于各自单独使用。大面积推广,5％氯氰菊酯乳油1500倍液防治枣飞象,5％氯氰菊酯乳油3000倍液、5％来福灵乳油4000倍液防治枣尺蠖、枣镰翅小卷蛾效果好。以5％氯氰菊酯乳油与40％久效磷乳油的1500倍混合液,一次施药同时防治上述三种害虫效果尤为显著。     

鞭角华扁叶蜂防治研究

对鞭角华扁叶蜂进行5年防治试验,在幼虫危害盛期用1:3000～2000倍20％氰戊菊酯乳油、1:1000倍50％甲胺磷乳油喷雾防治,幼虫越冬期的当年11月～次年2月对受害林地进行深翻,成虫羽化高峰期用1:1500倍50％甲胺磷乳油和80％敌敌畏乳油混合液喷雾防治均能达防治目的。     

苹果园山楂叶螨田间药剂防治试验

山楂叶螨的发生与高温干旱气候有关，叶螨繁殖盛期在7月上句。选用5种药剂进行叶螨防治试验，20％螨死净乳油2500倍液、40％水胺硫磷乳油1000倍液、灭扫利3000倍液防治效果较好；40％氧化乐果1000倍液和20％三氯杀螨醇乳油800倍液防治效果较差。     

树冠农药喷雾防治黄连木种子小蜂研究

应用3％啶虫脒乳油等5种低毒农药,采用树冠喷雾的方式开展黄连木种子小蜂防治试验。结果表明：适宜浓度下,五种低毒农药在树冠喷雾中对黄连木种子小蜂防治效果都在90％以上;396啶虫脒乳油、5％吡虫啉乳油、20％乙酰甲胺磷乳油、2．5％溴氰菊酯乳油、10％氯氰菊酯乳油五种农药防治黄连木种子小蜂最佳适宜浓度分别为1000倍、1200倍、600倍、1000倍、800倍;防治的最佳时期为6月上中旬。     

落叶松叶蜂发生规律及防治

落叶松叶蜂在太白林区1年发生1代，以老熟幼虫在林下枯枝落叶层内结茧越冬，是本林区落叶松的主要叶部害虫，以4～5龄幼虫为主要的害虫期。在树冠上部、疏林地、阴坡地带危害最严重。在1～2龄幼虫期采用80?V乳油1000倍液、2．5％溴氰菊酯乳油500～1000倍液或者50％甲胺磷1500倍液喷雾，也可施放林丹烟剂，均可取得良好的防治效果。     

梨喀木虱发生规律与防治技术研究

梨喀木虱1年发生6～7代，以成虫在树干裂缝、杂草、落叶中越冬，对早酥梨为害最严重；已发现天敌有多种蜘蛛及5目8科13种昆虫，在自然状态下天敌对梨喀木虱控制作用明显；不科学的化学防治是造成梨喀木虱危害加重的主要原因；用1．0％爱诺虫清3000倍液、20％梨虱霸乳油2000倍液、5％蚜虱净乳油1500倍液防治梨喀木虱效果都在95％以上，1．0％爱诺虫清是生物药剂，更宜推广。     

万兴乳油防治枣黑腐病试验

经过3a田间药效试验和示范表明，20．67％万兴乳油是防治枣黑腐病的优良杀菌剂，田间使用浓度以2500～3000倍为宜；发病前喷施68．75％易保1500倍和波尔多液，后期喷施万兴乳油，病果率可控制在5％以下。     

马蹄筋草坪害虫斜纹夜蛾的识别与防治方法

采用黑光灯或糖醋液诱杀成虫，对1－2龄幼虫喷洒90％敌百虫与马硫磷乳油800－1000倍混合液或50％敌敌畏乳油与50％辛硫磷乳油1000－2000倍混合液，3龄以上幼虫喷洒50％敌敌畏与50％甲胺磷1000倍混合液，均可取得较好的防治效果。     

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.