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桦三节叶蜂 Arge similis Vollenhoven危害桦树。在互助县北山林区一年发生 1代 ,以幼虫危害叶片 ,总食叶量可达 47.1 cm2 /头 ,桦三节叶蜂发生程度主要取决于气候条件 ,特别是温湿度适宜与否。其次是受越冬蛹茧基数、寄主树种的多寡以及天敌数量的影响 ,在防治上应采取综合防治措施 ,如人工消灭越冬蛹茧、营造混交林 ,保护天敌等方法 ,以减少幼虫发生量 ,药剂防治在卵刚孵化后的幼虫期效果最佳 相似文献
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桦三节叶蜂Ａｒｇｅ ｓｉｍｉｌｉｓ Ｖｏｌｌｅｎｈｏｖｅｎ危害桦树。在互助县北山林区一年发生１代，以幼虫危害叶片，总食叶量可达４７．１ｃｍ＾２／头，桦三节叶蜂发生程度主要取决于气候条件，特别是温湿度适宜与否。其次是受越冬蛹茧基数、寄主树种的多寡以及天敌数量的影响，在防治上应采取综合防治措施，如人工消灭越冬蛹茧、营造混交林，保护天敌等方法，以减少幼虫发生量，药剂防治在卵刚孵化后的幼虫期效果最佳。 相似文献
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两种药剂防治桦三节叶蜂效果分析 总被引：1，自引：0，他引：1
《湖北林业科技》2015,(6)
为了控制神农架林区桦三节叶蜂的危害,应用3%高渗苯氧威、1.2%烟碱·苦参碱两种药剂,采取喷烟和喷雾两种措施对桦三节叶蜂进行推广防治。用药48 h后,防效最佳,平均校正死亡率达到90.8%。在一般林地,采用喷烟的方法进行防治,以提高工作效率。在游人活动区、金丝猴等动物活动区、蜜蜂养殖场所附近,采取喷雾方法进行防治,以避免烟雾造成负面影响。防治时间应避开桦三节叶蜂的天敌羽化高峰期,以免对其天敌的造成较大伤害。 相似文献
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近年来,榆三节叶蜂发生严重,大大降低了榆树的园林景观效果,该文开展了榆三节叶蜂发生规律观测及防治试验。研究发现：榆三节叶蜂在沧州地区1a发生2代,以老熟幼虫在土中结丝质茧变为预蛹越冬。以幼虫取食各种榆树叶片危害,危害期集中在6月下旬至7月中旬、8月中旬至9月上旬。在防治榆三节叶蜂幼虫时,宜采用25%灭幼脲悬浮剂1500～2000倍液、苏云金杆菌乳剂1500～2000倍液、白僵菌可湿性粉剂800～1000倍液,4.5%高效氯氰菊酯乳油1000～1500倍液喷雾适用于虫龄较大或大发生时使用。防治效果均可达到90%以上。 相似文献
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马尾松吉松叶蜂（ＧｉｌｐｉｎｉａｍａｓｓｏｎｉａｎａＸｉａｏ）属松叶蜂科Ｄｉｐｒｉｏｎｉｄａｅ，是危害马尾松的一种新害虫，近年来在安徽滁县沙河集林业总场发生相当严重。经研究，此虫一年发生２代，以预蛹越冬。该幼虫的空间分布型为聚集分布，我们编制了“马尾松吉松叶蜂地面茧数”查定表；制定了防治指标；其防治适期为２—３龄幼虫出现高峰期：第１代为５月１５－３０日；第２代为１０月１０—２５日。以２．５％溴氰菊酯乳油２０００—５０００倍液等进行喷雾防治，效果均在９４％以上；以２．５％溴氰菊酯乳油等加柴油配成油烟剂进行喷烟防治，效果在９６％以上。 相似文献
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桦三节叶蜂(Arge pullata)是近年来湖北省神农架林区危害红桦的主要食叶害虫。为有效控制该害虫的蔓延和危害,应用新一代植物源农药2.8%木烟碱微囊悬浮剂对桦三节叶蜂进行防治试验,结果表明:利用2.8%木烟碱微囊悬浮剂低量10倍液处理或超低量5倍液处理,防治效果分别为97.41%和95.68%。试验为防治桦三节叶蜂最佳用药量等防治技术的推广应用提供了依据。 相似文献
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马尾松吉松叶蜂属松叶蜂科Ｄｉｐｒｉｏｎｉｄａｅ，是危害马尾松的一种新害虫，近年来在安徽滁县沙河集林业总场发生相当严重。经研究，此虫一年发生２代，以预蛹越冬。该幼虫的空间分型为聚集分布，我们编制了“马尾松吉松叶蜂地面茧数”查定表；制定了防治指标；其防治适期为２－３龄幼虫出现高峰期；第１代为５月１５－３０日；第２代为１０月１０－２５日。以２．５％溴氰菊酯乳油等加柴油配成油烟剂进行喷烟防治，效果在９６％ 相似文献
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《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
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《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
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《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
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《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
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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
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
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. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
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. 相似文献
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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):166-178
This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes. 相似文献