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1.
In Ireland, the grey field slug (Deroceras reticulatum) is the predominant slug pest species in arable crops. It can cause enormous damage, but the knowledge about its feeding biology is limited. Adult species were reared under laboratory conditions, and the survival, feeding activity, and weight change of slugs when feed on maize, peas, or wheat seeds were investigated. An especially high mortality was experienced in the wheat treatment. It was hypothesised that the high mortality was due to a Fusarium species, however, a Fusarium infection of the wheat seeds was not confirmed. The weight change of the slugs was very variable due to a high egg production of some slugs. A second experiment examined the food choice and feeding activity of D. reticulatum when offered a choice of the three seed types. Most of the slugs preferred to feed on a mixture of seeds, but the highest feeding activity was recorded on the pea seeds.  相似文献   

2.
Slugs (Lchmannia marginata Müller) were observed moving and feeding on chestnut blight cankers in woods. Preliminary laboratory tests support the hypothesis that slugs are important vectors in the natural spreading of the blight, complementary to other physical and biological factors.  相似文献   

3.
Staining the skin of larger slugs with dots of methylene-blue proved to be a simple, reliable and variable marking technique. The marks lasted for about 6 weeks; vitality and activity of marked slugs were not impaired. By use of marked slugs in a capture-recapture experiment the density ofA. rufus in a maize field could be estimated to be about 0.5 slugs/m2; a repetition gave the same result. Registration of marked slugs in artificial refuges showed thatArion rufus is vagrant. An experimental population had left a round area with a diameter of 20 m completely within 12 and 9 days resp., and was replaced by new immigrants. On lawn, singleA. rufus crawled between 3.5 and 12.8 m within one night; on asphalt, they made only between 1.1 and 5.8 m.  相似文献   

4.
5.
Species composition of galls on the leaves of Ulmus laevis Pall. was analysed in 2001?–?02 in the Mogilski Forest – near an urban agglomeration of Kraków. A total of 5830 galls were found. The galls were caused by 5 insect or mite species. Aceria ulmicola brevipunctata (Nalepa) was the most abundant species in both years. The index of occurrence frequency and Agrell's index of species co-occurrence have been calculated. The index of occurrence frequency (F) reached the highest value in the case of A. ulmicola brevipunctata, namely 1.740, in 2001, and the lowest value, i.?e. 0.00?005 for Schizoneura ulmi (Linné), in 2001. Agrell's index of species co-occurrence reached the highest values, i.?e. 0.500, in the case of A. ulmicola brevipunctata and Physemocecis ulmi (Kieffer), in 2002, and the lowest one, namely 0.050 for A. ulmicola brevipunctata and Schizoneura ulmi, in 2001.  相似文献   

6.
Abtract The system Vicia faba–Aphis fabae fabae was studied under the influence of Ocimum basilicum (basil) and Satureja hortensis, in a wind tunnel, in the greenhouse and in field experiments. In the wind tunnel at 20°C both Lamiaceae were deterrent for A. fabae, and S. hortensis proved to be more deterrent than O. basilicum. In experiments in the greenhouse at low temperatures (average minimum 14.6°C, average maximum 24.1°C), A. fabae colonised first and significantly more intense Vicia fabae (field beans) not surrounded by O. basilicum or S. hortensis. At high temperatures (average minimum 18.0°C, average maximum 38.5°C) this relation was inverted: Vicia faba surrounded by the two Lamiaceae were preferred for colonisation (Ocimum basilicum significantly). It showed that pots with Lamiaceae were no obstacle for the aphids to reach Vicia faba. In strip cropping in the field, the repellent effect of Ocimum basilicum proved to be stronger than of Satureja hortensis. In 2002 there was observed only a tendency of lower aphid attack of field beans intercropped with Lamiaceae, while in 2004 and 2005 the infestation of Vicia faba by Aphis fabae was significantly lower in plots intercropped with basil. In plots with Satureja hortensis as intercrop, Vicia faba were significantly lower infested, after 3 weeks. The differences between the results of the wind tunnel/greenhouse at low temperatures, and the field experiments concerning the deterrence by Satureja hortensis cannot be explained. But basing on our results with Ocimum basilicum and those published by other authors, it is recommended to follow up intercropping, after a sincere analysis in every case, in favour of agronomists.  相似文献   

7.
通过ITS-rpl16序列和mat K序列的分子分析,对中国现有金合欢属的各亚属间的亲缘关系进行了研究,结果表明:我国现有广义金合欢属的14个种大致被聚为相思亚属、皮刺亚属和金合欢亚属3大类,原产中国的3种皮刺亚属的种聚成1支,表明印度金合欢和羽叶金合欢关系更近,二者再与儿茶形成姐妹类群。基于选自美洲、非洲、澳大利亚和中国乡土种(印度金合欢、羽叶金合欢和儿茶)共40个金合欢属种和1个外类群的mat K序列建立的系统发育树表明:皮刺亚属和相思亚属的亲缘性关系比与金合欢亚属的亲缘关系更近,相思亚属和金合欢亚属均是单系类群,而皮刺亚属属于并系类群;中国的几个乡土种都与非洲一些种的亲缘关系较近,聚为1支。  相似文献   

8.
Varieties of rough rice, Oryzae sativa (L.), were obtained from different sources in the south-central United States and evaluated for susceptibility to the lesser grain borer, Rhyzopertha dominica (Fab.), and the Angoumois grain moth, Sitotroga cerealella (Olivier), in laboratory studies. Adult R. dominica were fed on the rice varieties for 2 weeks, removed, and assessed for progeny production after an additional 6 weeks. Sitotroga cerealella susceptibility was evaluated by exposing two mating pairs of moths on a particular variety until the adults died. Rhyzopertha dominica parental survival, progeny production, and feeding damage by parental and progeny adults were variable, with survival ranging from 19.4 to 95 %. Rhyzopertha dominica parental feeding damage, progeny production, and progeny feeding damage were all correlated (r = 0.35–0.97, P < 0.001). Parental feeding of R. dominica provided access for neonate larvae to infest the rice hull. All rice varieties supported development of S. cerealella, and the variety Vista, which did not support growth of R. dominica, was one of the most susceptible varieties to S. cerealella. Progeny production of both species was generally correlated, but we observed only two instances of specific correlation for any rice variety. Results show that differences in variety susceptibility to stored product insects and differential susceptibility among species are important factors to consider when developing insect pest management programs for stored rice.  相似文献   

9.
Observations on the predacious activity of Deroceras laeve Müll. (Mollusca: Limacidae)on eggs of Pegomyia betae Curt.(Muscidae) and Epilachna varivestis Muls.(Coccinellidae). Deroceras laeve was observed feeding on eggs ofPegomyia betae in the laboratory and in the field. Since little is known about predacious behaviour of species of Limacidae, tests were conducted on the food preferences in two sets of experiments: (1) eggs ofP. betae on sugar beet leaves and (2) eggs ofEpilachna varivestis on bush bean leaves. Eggs ofP. betae were preferred over sugar beet leaf tissue (Fig. 1 and 2). The results showed that the slugs in addition to feeding on the eggs consume small amounts of the surrounding plant surface tissue. The feeding on eggs, however, was not considered to be accidential, because on leaves lacking eggs or on leaves with decreasing number of eggs,D. laeve fed predominantly on the tissue of the leaf margin. In the other set of experiments withE. varivestis the slugs were also found feeding on eggs, but showed a higher preference for plant tissue when compared with P. betae (Table 1).  相似文献   

10.
Ten forest sites with a tree layer of almost pure beech in southern-central Scania, south Sweden, were studied. They were all located in the interior of large forest stands. Five of the stands were developed on mor Podzols with scanty or almost no ground layer vegetation. The other five sites were located on mull Cambisols with a rich ground layer of many vascular plant species and a shrub layer of varying density. In total, 42 carabid beetle species and 9260 individuals were captured with pitfall traps (15 per site, diameter 87 mm) during 12 weeks in April, July and September 2007. Composition of the carabid fauna differed considerably between the two types of sites. In the Cambisol sites 39 carabid species were found, compared to only 21 species in the Cambisol sites. Mean carabid species richness per site differed significantly between Cambisol and Podzol sites (n = 20.4 and 13.2, respectively). The difference was wholly due to a lower number of small carabid species (mean body length <12 mm) in the Podzol sites. Of four variables (pH-KCl, Clay, Organic matter, and Sum of plant cover percentages below tree canopy) the sum of plant cover variable usually accounted for more (>50%) of the carabid beetle variability compared to the three other variables. Carabus glabratus and Pterostichus oblongopunctatus were almost exclusively found on Podzol. Carabus coriaceus, Pterostichus melanarius and in particular Carabus nemoralis were more abundant on Cambisol, whereas Carabus hortensis and Pterostichus niger were almost ubiquitous and attained the highest total numbers. There was no significant difference between Podzol and Cambisol sites in the total number of carabid individuals captured. C. coriaceus, C. hortensis, and Carabus violaceus, species that were abundant enough in all sites for a comparison, had significantly larger mean body sizes in the Podzol than in the Cambisol sites, a finding valid for both sexes. There were more males than females of C. coriaceus, C. violaceus, and C. nemoralis in the catches, whereas sex distribution of C. hortensis was equal. Possible explanations for the findings are differences in microclimate and food web characteristics related to differences between Podzols and Cambisols in understorey vegetation and soil or litter properties.  相似文献   

11.
130?kg of acorns of Common Oak (Quercus robur L.) were distributed on an area of 1.44?ha in an oak forest near Zagreb (Croatia), where acorns were lacking. The influence of this surplus of food on the development of mice and voles was observed from September 1999 till February 2000 on the experimental plot and on an untreated control area before and after offering the acorns. The Redbacked Vole Clethrionomys glareolus was the most abundant and dominant species in both observed areas. After distribution of the acorns, all species of mice, e.?g. the Yellownecked Fieldmouse Apodemus flavicollis, the Longtailed Fieldmouse A. sylvaticus, and the Striped Field Mouse A. agrarius, increased up to 4 times in number on the area treated with a surplus of acorns. On the same area, however, all species of voles, e.?g. the Redbacked Vole C. glareolus, the Field Vole Microtus agrestis, and the Common Vole M. arvalis, decreased. The numbers of captured and recaptured rodents before and after offering acorns on the treated and the untreated control area were compared by statistical analysis (Chi2-test). The results show how food can influence the competitive relations between mice and voles.  相似文献   

12.
Modes of passive dispersal of the grape rust mite Calepitrimerus vitis (Eriophyoidea) were investigated in a vineyard of South-Western Germany. More than 200 Eriophyoidea per month were trapped in a wind chamber during summer (32,1?% C.?vitis) suggesting long-distance dispersal by air currents. Rain washed part of the adult C.?vitis population from the foliage. SE micrographs suggest that quiescent nymphs are affixed to the leaf by a substance of unknown nature. However, the role of rain in C.?vitis colonisation of uninfested vineyards is still unclear, as is the role of phoretic transport by arthropods. For the first time, evidence of rust mite dispersal by human activity is presented. A large number of C.?vitis was found adhering to clothes and hands of workers carrying out customary cultural practices in the vineyard. Other arthropods, including Typhlodromus pyri, the main predator of C.?vitis, were also passively transported by wind, rain and human activity.  相似文献   

13.
Three softwoods, Sugi (Cryptomeria japonica), Korean Pine (Pinus koraiensis) and Hinoki (Chamaecyparis obtusa), were vacuum–pressure impregnated with a fire retardant chemical consisting of ammonium phosphate polymer (APP), guanyl urea phosphate (GUP), phosphonic acid and a minor amount of additives. The variation in impregnation between and within wood species was investigated. A significant relationship and similar trends were found between fire retardant chemical (FR) uptake and specific gravity (SG), as well as void volume filled (VVF) and SG. Moreover, the effects of fire retardant treatment on mechanical properties, including modulus of rupture (MOR), static modulus of elasticity (MOE) and dynamic modulus of elasticity (DMOE), were evaluated. The results indicated that the trend of impregnation and regression function varied between species and positions within the same species. However, the relationship of SG and chemical uptake and that of VVF and chemical uptake could be represented by a positive linear regression, and the trends were similar between wood species. Both of SG and VVF increased with increasing FR uptake. After fire retardant treatment, the MOR and static MOE were reduced compared with before treatment. Conversely, the DMOE increased after treatment.  相似文献   

14.
The occurrence and symptoms of root and butt rot were examined in a 35 × 30 m plot of 68‐year‐old Todo fir plantation in Hokkaido, Japan. Forty‐seven percent of the cut stumps were decayed and 52% of the decayed stumps showed similar decay characteristics with yellowish orange to light brown colouration and expanded pockets in the heartwood. Morphological characteristics of the pure cultures isolated from the decay were similar to the cultures isolated from basidiocarps of Heterobasidion annosum sensu lato, found on fallen logs outside of the research site. Also DNA analysis based on the combined data set of three gene loci (glyceraldehyde 3‐phosphate dehydrogenase, heat shock protein 80–1 and elongation factor 1‐alpha genes) showed that the isolates from the decay are included in the same clade with the Japanese H. annosum s.l. isolates. They form a subclade to H. parviporum (the European S group of H. annosum s.l.). This is the first report of molecular determination of H. annosum s.l. isolated from root and butt rot in a plantation in Japan.  相似文献   

15.
The pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of the pine wilt disease, has been detected in several regions of Portugal affecting Pinus pinaster, a coniferous species of a great economic value. The nematodes, migrating through resin canals and feeding on parenchyma cells, induce rapid metabolic changes in ray parenchyma cells, cavitation areas, and denaturation and necrosis of parenchyma and cambial cells. To understand how anatomic changes and biochemical incidences of tree defense reactions affect the technological parameters of the wood, the gross calorific value (GCV) and chemical composition of PWN-infected and -uninfected P. pinaster wood were evaluated. The GCV was determined using Parr 6300 Automatic Isoperibol Calorimeter, and chemical composition analysis was performed by determining the contents of carbon, hydrogen, nitrogen, sulfur and Ash on complete and instant oxidation of samples by “flash” combustion. The Student’s t test with Welch correction was used for statistical data analysis. The difference between the GCV and chemical composition for PWN-infected and -uninfected P. pinaster wood was statistically significant for the GCV and for hydrogen and nitrogen contents. The carbon, oxygen, sulfur and Ash contents did not differ statistically. The GCV of PWN-infected wood varied between the highest value of hardwood and the lowest value of softwood. This interdisciplinary study stresses the important technological and economic aspects, namely the impact of PWN on wood properties and the suitability of infected P. pinaster wood for use in the wood-processing and energy industries.  相似文献   

16.
Berberis species are endangered, high-value medicinal plants in Pakistan with important eco-cultural, commercial and livelihood roles in mountain communities. To assess the geographical distribution of Berberis species across the Karakoram Mountain Ranges in Pakistan, we used IUCN Red List Categories and Criteria (2001) to calculate the extent of occurrence (EOO, <100 km2) and the area of occupancy (AOO, <10 km2) of Berberis pseudumbellata subsp. pseudumbellata and B. pseudumbellata subsp. gilgitica. Overgrazing and habitat loss were key population-limiting factors. The two subspecies had contrasting responses to temperature, elevation, precipitation and insect susceptibility. B. pseudumbellata subsp. gilgitica is endemic to Gilgit-Baltistan and grows in single-cropping zone (areas > 200 m a.s.l.). Status evaluation revealed that both subspecies meet the criteria set for critically endangered species. Prolonged disregard of its declining population trend might lead to its extinction; therefore, integrated conservation efforts are necessary.  相似文献   

17.
During an outbreak of the soybean semilooper,Plusia orichalcea F. in Jabalpur, the caterpillars not only caused heavy damages to the soybean crop but were also commonly feeding on many other plants growing in soybean fields and nearly bunds. A list of these alternative host plants containing 15 species of 6 families is given.  相似文献   

18.
Relative susceptibility of 23 Eucalyptus provenances of 11 species to pink disease caused by Corticium salmonicolor was assessed in culture filtrates of two isolates (CS1 from E. tereticornis and CS2 from E. grandis) of the pathogen, employing cut-shoot bioassay. The results showed statistically significant variation in response among different provenances within a species. Cut shoots of eucalypus giving susceptible response were affected significantly by the culture of filtrates at low dilutions, whereas those giving resistant response tolerated high concentration with little damage to shoots. This evidence clearly indicated an interaction between the host and culture filtrates of the pathogen. The response of CS1 and CS2 culture filtrates gave statistically significant differences in their reactions on various eucalypts, possibly indicating that the isolates are of two different strains. The criticism of cut-shoot bioassay and its significance in laboratory screening of eucalypts to pink disease are discussed.  相似文献   

19.
Agroforestry is a promising method for enhancing land-use sustainability in the Bolivian Andes. However, its benefits in terms of rural development are under-recognized due to gaps in understanding users?? perceptions while taking into consideration both local and global environmental goals. Our study aimed to narrow these gaps by developing an analytical framework for analyzing the site-specific socio-ecological factors and interactions related to local woody species and assessing their ecological, economic, and socio-cultural plant values in order to identify the most promising agroforestry species. The framework was then tested in an indigenous community at 2,760?C3,830?m?a.s.l., incorporating vegetation surveys, environmental studies, and interviews on plant functions. Ecological, economic, and socio-cultural values and the ecological apparency of plants were calculated, and detrended correspondence and principal component analyses helped to reveal the socio-ecological context of significant factors for plant distribution and uses. Results showed dominating seral woody species along an altitudinal gradient. Although shrubs were more ecologically apparent than trees, trees were perceived to be more valuable as the usefulness and cultural importance of species increased with plant height and timber availability. Phytosociological factors played a minor but still significant role in perceived usefulness. Schinus molle and Prosopis laevigata (<3,200?m a.s.l.), Polylepis subtusalbida (>3,200?m a.s.l.), and Baccharis dracunculifolia (both zones) were evaluated as most promising for agroforestry use. In conclusion, our analytical framework proved to be a valuable tool for context-specific agroforestry plant selection. Nonetheless, economic, technical, and socio-cultural limitations of cultivating native agroforestry species were revealed as well. Agroforestry science and practice should, therefore, focus on enhancing reproductive potentials of existing woody vegetation, as well as problem-oriented horizontal dialogues between indigenous, expert, and scientific actors.  相似文献   

20.
This study was conducted to analyze the stand structure of Quercus mongolica forests in Korea and to understand their regeneration dynamics. Forest community types of Mt. Joongwang, Mt. Chiri and Mt. Worak were classified into 7 groups by TWINSPAN. Q. mongolica appeared mainly on mid to upper slope positions. Acer mono, A. pseudo-sieboldianum, Maackia amurensis and Tilia amurensis are commonly associated with Q. mongolica. The density and basal area of Q. mongolica decreased as the stand developed into pole and early-mature stage forests. Total number of species increased as stands developed. Q. mongolica is an early invader of disturbed areas and dominates the stand, which means that this species should be considered as a pioneer species rather than a climax. Germination rate of scattered acorns was very low but fallen leaves over the acorns protected them from animal feeding and raised the germination rate. Among the seedlings of Q. mongolica, more than 70% originated from seedling sprouts. They showed a higher growth potential than seedlings, and their heartwoods are decay resistant. Therefore, their number and size were very important factors in determining the species composition of future forests after clearcutting.  相似文献   

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