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1.
捕食性昆虫螨类及蜘蛛的捕食作用   总被引:5,自引:0,他引:5  
文章综述了昆虫、螨类及蜘蛛捕食作用研究的近况,重点介绍了昆虫及捕食性螨类和蜘蛛的捕食功能反应,血清学法研究捕食作用的概况,分析了ELISA法的优缺点,并总结了捕食作用的研究现状,指出了面临的问题及发展方向。  相似文献   

2.
Despite widespread recognition of linkages between vegetation and insects, understanding of the ecological mechanisms underlying these relationships is limited. Better comprehension of relationships linking abundance and biomass of insects to vegetation would increase accuracy of predictions of the effects of forest management activities on insect communities. This knowledge could also be pivotal to understanding predator–prey dynamics linked to insect populations. We sampled nocturnal flying insects and measured vegetation characteristics in 34 stream reaches in conifer-dominated forests of the Oregon Coast Range in the Pacific Northwest of the United States. We considered five a priori hypotheses (resource quality, resource diversity, resource abundance, resource concentration, and stream cover hypotheses) that could explain mechanisms underlying associations between riparian vegetation and nocturnal flying insects, and used an information-theoretic approach to determine the relative strength of evidence for each. The resource quality hypothesis, which predicts that abundance and biomass of insects increases with cover of deciduous vegetation, explained substantial variation for nearly every order of insect investigated, whereas the remaining hypotheses explained relatively little. Abundance and biomass of insects had stronger associations with characteristics of canopy trees than with characteristics of shrub or understory trees, suggesting that deciduous trees are an important habitat element for nocturnal flying insects in these areas. Resource managers planning riparian vegetation management in conifer-dominated forests should be aware that manipulation of the cover of deciduous trees in riparian areas could have a large impact on these insects and their vertebrate predators. By providing information on forest canopy composition, remote sensing may offer a low-cost tool for identifying areas with high abundance and biomass of insects during conservation planning.  相似文献   

3.
4.
Agrotis ypsilon andSpodoptera littoralis can be successfully controlled on various field crops usingBacillus thuringiensis (Dipel 2X) baits and sprays. Baits based on the pathogen at 200–250 g/Feddan, scored the best efficacy againstA. ypsilon in clover fields followed by potato, tomato, and cotton cultivations. Addition of some chemical additives (inorganic salts) toB. thuringiensis bait formulations greatly enhanced its potency. This was associated with an obvious increase in the yield of clover, potato and tomato crops; calcium oxide showed to be highly afficient in this respect. Sprays of Dipel 2X were also found as affective as lannate in controllingS. littoralis on clover cultivations.
Zusammenfassung Die Untersuchungen ergaben, daßAgrotis ypsilon undSpodoptera littoralis an verschiedenen Feldfrüchten erfolgreich mitBacillus thuringiensis (Dipel 2X) als Köder oder Sprühmittel bekämpft werden können. Die Köder auf der Grundlage von 200–250 gBacillus/Feddan erzielten die besten Ergebnisse gegenA. ypsilon auf Kleefeldern, gefolgt von Kartoffel, Tomate und Baumwolle. Die Beimengung von chemischen Zusatzmitteln (anorganische Salze) zu denBacillus-Ködern erhöhte die Wirksamkeit beträchtlich. Daraus resultierte eine auffallende Steigerung der Klee-, Kartoffel- und Tomatenernte. Dabei war Kaliumoxid das wirksamste Zusatzmittel. Das Sprühen mit Dipel 2X erwies sich in Kleefeldern als ebenso wirksam wie die Anwendung des chemischen Pestizids Lannate.


With 4 tables  相似文献   

5.
Faidherbia albida (Del.) A. Chev. is an important tree species of the scattered tree or parkland systems in the Sahel. The improved crop growth under its canopy is well known, and has been attributed to various components notably: higher soil fertility, improved microclimate and better soil physical properties. The relative contributions of each of these components are not known, but knowledge about this is essential for making proper decisions concerning management options. The overall tree effect on crop production (expressed as fraction of the sole crop production) is analysed here as a weighted sum of (positive and negative) relative net tree effects on the resources for crop growth. In this sum, the weights reflect the degree of limitation of the resources in the environment at the tree-crop interface. The paper shows how the relative net tree effects and the accompanying weights can be estimated from field experiments. In an on-farm field experiment in Niger, millet production under the F. albida canopy was about 36% higher than in the open field. The nitrogen availability under trees was estimated to be more than 200% higher than in the open causing a 26% production increase. The phosphorus availability was estimated to be almost 30% higher and because of its high limitation causing a production increase of 13%. The net effect via other resources (notably light and water) was negligible (3% production reduction) and not significant.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

6.
A field trial was conducted to investigate the use of peas (Pisum sativum cv. Valverde), wheat (Triticum aestivum cv. Capo) and oilseed radish (Raphanus sativus var. oleiformis cv. Adagio) as trap crops to control wireworm in potato fields. We investigated the efficacy of trap crops and distance of attraction by counting larvae in both potato and trap crop rows. Wireworms of the genera Agriotes, Adrastus and Hemicrepidius were observed. In the plots planted with peas as a trap crop, significantly more wireworms were observed than in the other treatments, which was clearly due to the influence of the trap crop pea. The potato rows 0.75 m away from the peas showed 2.4 times more larvae than the potato rows 1.5 m away. This may be due to a decrease of the peas’ attractiveness over time (Miles and Petherbridge 1927), with wireworms that were initially attracted to the peas moving back to the nearby potatoes. In the plots planted with wheat, oilseed radish and the control (bare soil instead of a trap crop), there was no significant difference in numbers of larvae between the potato rows. In the control plots, significantly more larvae were found in the potato rows than in the bare soil. We assessed the damage to potato tubers by weighing them and counting the wireworm holes. Our results indicate that peas are more attractive to wireworms than potatoes and might be an effective trap crop if the right timing and spacing relative to the potatoes is found.  相似文献   

7.
This review highlights the latest findings regarding the use of entomopathogenic nematodes against post-harvest insects. Due to their requirements for moisture, entomopathogenic nematodes had received, until lately, limited attention for application to the dry storage environment. Recent improvements of their formulation and application approaches, as well as the discovery of new, more virulent strains have enhanced the efficacy of entomopathogenic nematodes and renewed interest in using entomopathogenic nematodes in the stored-product environment. The nematode species tested against storage insects belong exclusively to the genera Steinernema and Heterhorhabditis. The virulence of entomopathogenic nematodes against post-harvest insects varies depending on the nematode species and strain. Usually, only a single-nematode species or strain is not equally effective against all major stored-product insect pests; therefore, one nematode strain or species cannot be suitable for controlling all species present in the storage environment, where several insect species coexist. The successful application of entomopathogenic nematodes in storage environments for controlling post-harvest insects is highly dependent on several biotic and abiotic factors, such as the host life stage, temperature, and relative humidity. Entomopathogenic nematodes have still to overcome substantial hurdles to become a reliable alternative for commercial applications in warehouses and storage facilities. However, the use of innovative, enhanced methods of formulation and application, such as encapsulation or bait traps, could boost the exploitation of entomopathogenic nematodes in storage facilities against post-harvest insects.  相似文献   

8.
利用昆虫性信息素防治杨树蛀干害虫技术试验   总被引:3,自引:0,他引:3  
本文通过在四旁、林网释放这两种害虫的昆虫性信息素对害虫的生物学特性、防治效果进行了试验性研究。通过试验表明这两种害虫的性信息素在害虫监测预报方面应用价值极高、防治效果十分显著,其杀虫效果、防治成本等方面均优于常规方法,具有极大的推广价值。  相似文献   

9.
大突肩瓢虫Synonycha grandis对居竹伪角蚜Pseudoregma bambusicola和绿竹链蚧Bambusaspis notabile、密竹链蚧B.miliaris等绿竹主要害虫具有较强的捕食能力。了解捕食性天敌的捕食行为是有效选择天敌用于生物防治成败的关键,为此,观察研究了大突肩瓢虫捕食居竹伪角蚜的行为以及各种行为时间分配。结果表明:大突肩瓢虫捕食行为分为搜寻、取食、清洁、静息、整翅、排泄6个过程,以积极搜索式为主,偶见坐等捕食。幼虫无展翅和清洁行为,且排泄和静息行为较少发生。在饥饿状态下,成虫整个捕食过程各行为所占的时间由长到短依次为取食时间、搜寻时间、静息时间、清洁时间,取食时间占观察总时长的47.02%;各龄幼虫的取食时间显著长于搜寻时间,虫龄越大,取食时间越长;嚼食时间随虫龄的增大而缩短,成虫的嚼食时间显著短于幼虫。  相似文献   

10.
The sustainable management of vole populations to reduce crop damage requires a reliable estimation of rodent density. The present study was conducted in 2011 in Asturias (NW, Spain) and aimed at developing a method for estimating the density of the water vole Arvicola terrestris cantabriae and the Lusitanian pine vole Microtus lusitanicus in apple orchards based on their presence signs. Previously, as A. t. cantabriae and the Iberian mole Talpa occidentalis occur simultaneously in the same habitats, we had to determine if earth mounds caused by these two species may be accurately differentiated. The results showed that presence signs may be used to discriminate the occurrence of A. t. cantabriae and T. occidentalis in areas of sympatry. The characteristics most interesting for species differentiation were the linear distribution pattern of the mounds and the occurrence of ‘earth sausages’ and ‘earth paths’, all of them typical of moles. The high correlation coefficients (r s ?>?0.88) obtained between animal captures and the presence of activity signs for the two vole species revealed that it is possible to estimate A. t. cantabriae and M. lusitanicus densities by using the presence signs. An estimating model adapted for apple orchards and for simultaneous sampling both voles is proposed. In addition, we confirmed that the three mammal species coexist frequently in the same orchards. The negative relation between A. t. cantabriae and M. lusitanicus numbers suggests a competitive displacement between species. The results of the present study have valuable applications for both crop protection and research purposes.  相似文献   

11.
湖南药用昆虫资源的开发利用研究   总被引:3,自引:1,他引:3  
湖南省自然条件优越,药用昆虫资源较为丰富,种类繁多。作者从药用昆虫种类、药用价值、开发利用现状等方面进行了论述,提出了开发利用的具体措施。  相似文献   

12.
Temporal land use/land cover (LULC) change information provides a variety of applications for informed management of land resources. The aim of this study was to detect and predict LULC changes in the Arasbaran region using an integrated Multi-Layer Perceptron Neural Network and Markov Chain analysis. At the first step, multi-temporal Landsat images (1990, 2002 and 2014) were processed using ancillary data and were classified into seven LULC categories of high density forest, low-density forest, agriculture, grassland, barren land, water and urban area. Next, LULC changes were detected for three time profiles, 1990–2002, 2002–2014 and 1990–2014. A 2014 LULC map of the study area was further simulated (for model performance evaluation) applying 1990 and 2002 map layers. In addition, a collection of spatial variables was also used for modeling LULC change processes as driving forces. The actual and simulated 2014 LULC change maps were cross-tabulated and compared to ensure model simulation success and the results indicated an overall accuracy and kappa coefficient of 97.79% and 0.992, respectively. Having the model properly validated, LULC change was predicted up to the year 2025. The results demonstrated that 992 and 1592 ha of high and lowdensity forests were degraded during 1990–2014,respectively, while 422 ha were added to the extent of residential areas with a growth rate of 17.58 ha per year. The developed model predicted a considerable degradation trend for the forest categories through 2025, accounting for 489 and 531 ha of loss for high and low-density forests, respectively. By way of contrast, residential area and farmland categories will increase up to 211 and 427 ha, respectively. The integrated prediction model and customary area data can be used for practical management efforts by simulating vegetation dynamics and future LULC change trajectories.  相似文献   

13.
Transgenic expression of antimicrobial peptides in crops has become a novel approach among the strategies to combat phytopathogens in modern plant protection measures. The first antimicrobial transgenes of insect origin, modified cecropins, have been demonstrated to confer resistance of several transgenic cultivars against both bacterial and fungal phytopathogens. Insects represent a promising reservoir for antimicrobial peptides to engineer disease resistant crops. The increasing knowledge about the potent insect innate immunity may help to develop a novel strategy in sustainable agriculture. Several approaches are presently under investigation to prevent evolution of phytopathogens that can overcome disease resistance in transgenic crops expressing an insect antimicrobial peptide. Pathogen-induced expression of insect antimicrobial peptides in crops and combined multiple expression of different antimicrobial peptides along with proteinase inhibitors from insects may prevent selection of resistant phytopathogens. The potential of insect antimicrobial peptides as transgenes to render disease resistant crops has just started to be explored and may provide tools to be ahead of the evolutionary adaptability of phytopathogens.  相似文献   

14.
木麻黄虫害研究概述   总被引:1,自引:0,他引:1  
木麻黄是我国东南沿海防护林的主要树种。文章综述了国内外木麻黄虫害研究概况。着重介绍了蛀干害虫星天牛、多纹豹蠹蛾、相思拟木蠹蛾和食叶害虫木毒蛾、棉蝗等在营林技术、林木抗虫性、生物和化学防治上的具体进展。  相似文献   

15.
Multi-functional silvopastoral systems provide a wide range of services to human society including the regulation of nutrients and water in soils and the sequestration of atmospheric carbon dioxide (CO2). Although silvopastoral systems significantly contribute to enhance aboveground carbon (C) sequestration (e.g. C accumulation in woody plant biomass), their long-term effects on soil C pools are less clear. In this study we performed soil physical fractionation analyses to quantify the C pool of different aggregate fractions across three land use types including (1) silvopastoral system with ash trees (Fraxinus excelsior L.), (2) planted woodland with ash trees, and (3) permanent grassland, which were established in 1989 at Loughgall, Northern Ireland, UK. Our results show that 26 years after the conversion of permanent grassland to either silvopastoral or woodland systems, soil C (and N) stocks (0–20 cm depth) did not significantly change between the three land use types. We found, however, that permanent grassland soils were associated with significantly higher C pools (g C kg?1 soil; P < 0.03) of the large macro-aggregate fraction (> 2 mm) whereas soil C pools of the micro-aggregate (53–250 μm) and silt and clay (< 53 μm) fractions were significantly higher in the silvopastoral and woodland systems (P < 0.05). A key finding of this study is that while tree planting on permanent grassland may not contribute to greater soil C stocks it may, in the long-term, increase the C pool of more stable (recalcitrant) soil micro-aggregate and silt and clay fractions, which could be more resilient to environmental change.  相似文献   

16.
项目通过参与式土地利用规划方法,重视农村妇女在项目中的参与程度,增加了农村妇女的赋权,使当地农村妇女为项目的顺利实施做出了贡献。  相似文献   

17.
Shifting cultivation is one of the main factors that has caused forest degradation in many tropical countries. In Sabah, Malaysia, the government has granted land titles to local farmers outside the Forest reserve, and introduced tree cash crops to reduce farmers’ dependence on shifting cultivation. Granting land titles, however, was not always an incentive for farmers to plant tree cash crops. Farmers often planted tree cash crops on land without secure legal rights. The Land Ordinance and illegal logging had introduced exclusive and (semi-)permanent rights to land into this region, and the Forest reserve also was divided among villagers. The Land Ordinance stipulates that planting trees confers permanent heritable and transferable rights of use and occupancy but not within Forest reserves. Local farmers who were anxious about their land rights believed that they could obtain those rights even within the Forest reserve, and applied for land titles. Farmers planted tree cash crops not only for future income but also to secure their land rights. At present, the policy of Forest reserve has nearly collapsed in this region and it is impossible to neglect or remove local farmers if the government utilizes Forest reserves for any purpose. Lands in the interior regions will be reclassified in the near future out of necessity.  相似文献   

18.
Thailand aims to increase the use of renewable and alternative energy by 25% of total consumption under the Alternative Energy Development Plan (AEDP 2012–2021) by 2021, which include outputs from energy crops. This initiative is likely to put pressure on land resources, especially near parks and protected areas. Our study examined energy crop plantations, farmer responses to the AEDP, and community roles in forest protection in four villages adjacent to Phu Wiang National Park, Thailand in 2014. The majority of respondents (80%, n = 50) used their land for rice cultivation, but many villagers increased plantings of sugarcane (54%) and cassava (20%) because of high market demand for energy crops. Only a few examples of agricultural expansion into the national park were observed. Nevertheless, encroachment is likely to occur at this and other national parks as a result of government incentives to plant energy crops and the limited availability of agricultural land. Reliance on community-based management strategies may not be powerful enough for villagers to withstand the pressures of modernization, materialism, and other socioeconomic influences, possibly negating the effect of sustainability. Striking an equitable balance between government policies, community development, and forest protection will be a challenge for resource managers.  相似文献   

19.
Selective logging is one of the main economical activities in tropical and subtropical forests. While most of the effects of this activity on bird communities have been studied by comparing exploited vs. non-exploited areas; the use of human-created treefall gaps by birds is relatively unknown. We studied habitat structure, resource abundance (fruits, flowers and arthropods) and bird activity in logging gaps of different age (1-year-old and 10- to 20-year-old) in a mountain forest (Yungas) of northwest Argentina in both dry and wet seasons. In less than a year after creation, short herbs colonize logging gaps increasing the abundance of arthropods in the ground and the activity of understory insectivores. During dry seasons recently created gaps become an important source of resources for understory frugivores-insectivores. Later on in succession logging gaps are invaded by exotic graminoid vegetation and tall herbs (dispersed through extraction tracks) which can impede the colonization and development of pioneer trees and natural regeneration. Probably as a consequence of a high abundance of fruits and flowers in the understory and a very low abundance of these resources in the canopy, old gaps were mainly used by understory frugivores-insectivores while arboreal frugivores were rare. Because arboreal frugivores disperse most tree seeds in tropical and subtropical forests, the low activity of this guild in logging gaps contribute to the low observed regeneration. Sustainable timber harvest in tropical and subtropical forests should include gap and logging track management to minimize the invasion by exotic graminoid vegetation and facilitate natural succession.  相似文献   

20.
克拉玛依地区人工林病虫害调查初报   总被引:1,自引:0,他引:1  
2003—2004年,首次对克拉玛依市所属的克拉玛依区、白碱滩区、乌尔禾区、独山子区、小拐乡、乌尔禾乡的人工林常见病虫害进行了全面系统的调查。经鉴定病虫害共153种,其中害虫123种,病害30种。  相似文献   

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