共查询到20条相似文献，搜索用时 78 毫秒
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旋纹潜叶蛾Leucoptera scitella Zeller是危害板栗的主要害虫,在浙江省绍兴市1 a发生4代.以蛹在枝干树皮缝或枝叉处结茧越冬,翌年4月中旬越冬代成虫羽化并产卵,4月下旬第1代幼虫孵化,5月中旬幼虫老熟并结茧,5月下旬1代成虫羽化并产卵.6月上旬第2代幼虫孵化,下旬化蛹,7月上旬第2代成虫羽化并产卵,7月中旬第3代幼虫孵化,8月上旬化蛹、成虫羽化并产卵,8月中旬出现第4代幼虫,9月下旬开始结茧化蛹越冬.在第1代幼虫期,用1.8%阿维菌素乳油1 000倍液、5%吡虫啉乳油1 000倍液和生绿Bt可湿性粉剂800倍液喷雾防治,5 d后效果分别达到97.2%,98.0%和85.7%. 相似文献
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桉树油桐尺蛾生物学特性及防治试验 总被引：2，自引：0，他引：2
在福建省仙游县开展桉树林油桐尺蛾的生物学特性观察与防治试验,结果表明:在福建仙游油桐尺蛾1 a发生3代,以蛹在土里越冬;翌年4月上旬—中旬成虫开始羽化,4月下旬为羽化盛期;第1代幼虫5月上旬孵出,5月下旬开始结茧化蛹,6月上旬成虫羽化,6月中旬为羽化盛期;第2代、第3代幼虫分别在7月上旬、9月中旬孵化,第3代幼虫10月下旬结茧化蛹进入越冬状态。采用溴氰菊酯烟雾剂进行应急化学防治可迅速降低虫口,灭幼脲Ⅲ号1 000倍液喷雾防治可控制该虫的危害。 相似文献
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杨小舟蛾生物学特性的初步观察 总被引：6，自引：0，他引：6
杨小舟蛾在白城地区1年发生2代,以蛹越冬。6月上旬为成虫羽化始期,6月中旬为羽化高峰期,成虫羽化后即交尾产卵。第2代幼虫出现在7月上旬,7月中旬为幼虫孵化高峰期,8月上旬开始化蛹准备越冬。 相似文献
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对光周期和温度对美凤蝶峨眉种群滞育诱导的影响进行了研究,结果表明:光周期对美凤蝶滞育的诱导作用与温度有关,在20℃的恒温条件下,光照在12～13 h范围内,随着光照时间的缩短,滞育个体增加,在光照时间短于12.5 h后达到100%;在25℃时,光照时间在11～13.5 h范围内,随光照时间的缩短,滞育率增加,但没有出现全部个体滞育的情况,最高滞育率为94.5%;在30℃时,在实验光周期范围内没有出现滞育个体.温度对滞育的影响受光周期的影响,在相同光照条件下,在一定温度范围内,随着温度的上升,滞育率下降,当温度上升幅度达到30℃,无论长短光照条件下均不出现滞育个体.只有在短光照条件下,低温才有利于滞育,而长光照和高温则有利于个体的发育而抑制滞育产生.短光照对滞育的诱导作用具有累积效应.在20℃恒温条件下,美凤蝶的临界光周期为LD 13 h 11 min:10 h 49 min;而在25℃恒温条件下,美凤蝶的临界光周期为LD 12 h 49 min:11 h 11 min.随着温度的升高,临界光照长度缩短.美凤蝶对光周期的敏感期为5龄幼虫. 相似文献
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观察了人工气候箱中不同光周期和温度条件下美凤蝶幼虫生长发育.结果表明:光周期和温度对美凤蝶幼虫发育历期影响明显;在相同温度下,不同光周期下幼虫历期差异明显;在20℃12～14 h,25℃11～15 h、30℃11～15 h光照下,历期分别为39.3～48.5、25.4～36、19.6 29 d,最长和最短历期分别相差9.2、10.6、9.6 d.随着温度升高,在相同光照下,幼虫发育历期缩短;在12.0、12.5、13.0、13.5、14.0 h光照下,幼虫发育起点温度分别为13.6、13.3、9.2、12.2、7.5℃,有效积温分别为332.7、340.5.372.1、350.9,475.4日度;光周期对幼虫的发育起点温度和有效积温有一定影响. 相似文献
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柑橘凤蝶非滞育蛹、滞育蛹和滞育蛹羽化成虫水份含量变化比较 总被引：1，自引：0，他引：1
为了进一步了解柑橘凤蝶滞育机理,利用重量法,测定了非滞育蛹、滞育蛹和滞育蛹羽化成虫不同发育阶段水份含量。结果表明,非滞育蛹水份含量在77．2193％-81．3552％之间,相对较高;滞育蛹水份含量在67．1469％-75．0716％之间,除11月下旬水份含量下降较多外其余时期水份含量相对稳定,相对较低,并呈现一定规律波动。滞育蛹羽化成虫水份含量为66．3596％,含量较低。非滞育蛹、滞育蛹和滞育蛹羽化成虫水份含量与变化差异表明,三者有不同的水份代谢特征。滞育蛹不同发育阶段水份含量变化与滞育蛹的发育阶段有关。 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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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
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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
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《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
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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