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1.
思茅松毛虫质型多角体病毒的应用 总被引：8，自引：0，他引：8
应用思茅毛虫质型角体病毒ＤｅｎｄｒｏｌｉｍｕｓｋｉｋｕｃｈｉｉＣｙｔｏｐｌａｓｍｉｃＰｏｌｙｅｄｒｏｓｉｓＶｉｒｕｓ（ＤｋＣＰＶ）防治思茅松毛虫Ｄｅｎｄｒｏｌｉｍｕｓｋｉｋｕｃｈｉｉ和文山松毛虫Ｄ．ｐｕｎｃｔａｔｕｓｗｅｎｓｈａｎｅｎｓｉｓ的实验证明用ＤｋＣＰＶ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。 相似文献
2.
德昌松毛虫质型多角体病毒防治大柏毛虫应用研究 总被引：1，自引：0，他引：1
应用德昌松毛虫质型多角体病毒Ｄｅｎｄｒｏｌｉｍｕｓ ｐｕｎｃｔａｕｓ ｔｅｃｈａｎｇｅｎｓｉｓ Ｃｙｔｏｐｌａｓｍｉｃ ＰｏｌｙｈｅｄｒｏｓｉｓＶｉｒｕｓ防治四川内地柏木林区大柏毛虫Ｄ．ｈｏｕｉＬａｊｏｎｑｕｉｅｒｅ的试验表明,以７．５×１０＾９ＰＩＢ／６６６．６ｍ＾２以上剂量防治３龄幼虫,其综合防效达８５％以上,且具有显著的扩散流行和持续防治效果 相似文献
3.
该文探讨了荒漠地区黄褐天幕毛虫ＭａｌａｃｏｓｏｍａｎｅｕｓｔｒｉａｔｅｓｔａｃｅａＭｏｔｓｃｈｕｌ－ｓｋｙ幼虫的食叶量。人工模拟不同摘叶强度对胡杨高、径生长量的方差分析及多重比较，Ｆ＞Ｆ０．０１，Ｄ＞Ｄ＊，摘叶３０％、５０％与摘叶１００％之间高、径生长量差异极显著。掌握了胡杨１００ｃｍ标准枝承受的害虫幼虫数及允许受害密度，建立了胡杨幼树单株材积生长量的一元回归方程：Ｙ＝２７．６８１８１＋２５１４２．３５９５７Ｘ。提出天幕毛虫幼虫防治指标：３．４头／１００ｃｍ标准枝，投入防治费用等于挽回经济损失的危害比例为３３．４％，即害虫幼虫危害大于摘叶３３．４％以上，则应立即防治。 相似文献
4.
在Ｄｐｔ ＣＰＶ防治后的德昌松毛虫林区内，通过林间调查及室内镜检连续观测松毛虫的带毒率及感病死亡率。结果 Ｄｐｔ ＣＰＶ的持续效果明显，Ｄｐｔ ＣＰＶ能通过带毒成虫产卵传给子代，并引起幼虫大量感病死亡，蛹重，羽化率，产卵量明显下降；与化防区相比天敌昆虫明显增加，能控制松毛虫５年以上有虫不成灾，郁闭度大的林分已长达１２年； 相似文献
5.
思茅松毛虫的初步研究 总被引：4，自引：0，他引：4
思茅松毛虫Ｄｅｎｄｒｏｌｉｍｕｓ ｋｉｋｕｃｈｉｉ Ｍａｔｓｕｍｕｒａ于１９８６年在首次发现，经３年调查研究，我市１年仅发生１代，幼虫有７龄，４龄越冬，多发生在海拔５００ｍ以上短叶松林中，并已基本摸清该虫在本市的分布及各虫态，虫龄的发生期与历期。 相似文献
6.
人工招引鸟类防治柏毛虫 总被引：1，自引：0，他引：1
人工招引鸟类防治柏毛虫＊崔传顺１杜克国２郭恒芳１王廷光１刘广玺３黑峪林场是历城区的第２大国营林场，林分主要为侧柏纯林，其主要害虫为柏毛虫Ｄｅｎｄｒｏｌｉｍｕｓｓｕｆｆｕｓｌｕｓ。该场柏毛虫１９７１年开始发生危害，１９７３～１９７５年暴发成灾，１９７６... 相似文献
7.
AcNPV病毒试验初报 总被引：1，自引：0，他引：1
用 Ａｃ Ｎ Ｐ Ｖ 病毒对德昌松毛虫 Ｄｅｎｄｒｏｌｉｍ ｕｓ ｐ ｕｎｃｔａｔｕｓ ｔｅｈｃｈａｎｇｅｎｓｉｓ Ｔｓａｉｅｔ Ｌｉｕ 进行初感和回感试验,采用浓度为 １×１０５ Ｐ Ｉ Ｂ／ｍ ｌ,第 １６ 天的死亡率达到 ９８％ ,用同一浓度回感试验,第１４ 天的死亡率达到 １００％ ,效果较明显。 相似文献
8.
黄褐天幕毛虫幼虫食叶量观测及防治指标的测定 总被引：4，自引：0，他引：4
该文探讨了荒漠地区黄褐天幕毛虫Ｍａｌａｃｏｓｏｍａ ｎｅｕｓｔｒｉａ ｔｅｓｔａｃｅａ Ｍｏｔｓｃｈｕｌｓｋｙ幼虫的食叶量。人工模拟不同摘叶强度对胡杨高、径生长量的方差分析及多重比较,Ｆ〉Ｆ０．０１,Ｄ〉Ｄ。摘叶３０％、５０％与摘叶１００％之间高,径生长量差异极显著。掌握了胡杨１００ｃｍ标准枝承受的害虫幼虫数及允许受害密度,建立了胡杨对单株材积生长量的一元回归方程：Ｙ＝２７．６８１８１＋２５１４２ 相似文献
9.
介绍了蜡质毒笔的生产工艺及使用方法。防治试验结果表明蜡质毒笔涂环防治柿毛虫（ｌｙｍａｎｔｒｉａｄｉｓｐａｒ）杀虫率高，蜡毒环经雨水冲刷以后不影响药效，在密封的环境中蜡毒笔保存１年防治柿毛虫的校正死亡率仍达９４．５％。 相似文献
10.
为害水杉和银杏的标毛虫ｐａｒａｌｅｂｅｄａｐｌａｇｉｆｅｒａｗａｌｋｅｒ幼虫经人工感染核型多角体病毒（ＰｐＮＰＶ）后，第４天便开始出现死亡，２５天内最高死亡率可达９０％。病毒的致死中浓度（ＬＣ５０）为１．４９×１０４±３×１０２ＰＩＢ／ｍｌ（Ｐ＝０．５）．害虫死亡率与感染浓度呈正相关，试验表明ＰｐＮＰＶ对栎毛虫有较强的毒力。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
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. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
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. 相似文献
13.
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. 相似文献
14.
《Scandinavian Journal of Forest Research》2012,27(2):118-130
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. 相似文献
15.
Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
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. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
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. 相似文献
17.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
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. 相似文献
18.
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。 相似文献
19.
Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
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. 相似文献
20.
《Wood material science & engineering》2013,8(2):76-84
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. 相似文献