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1.
The cabbage whitefly,Aleyrodes proletella, has developed to a key pest in brassica vegetable crops throughout Germany. In a 3-year project we investigated a biotechnical approach employing netting (0.8?×?0.8 mm meshsize) in combination with the native parasitoidEncarsia tricolor in an inoculative-inundative approach in organic Brussels sprouts under field conditions. In small scale plot experiments continuous netting from transplanting in May till October alone reduced whitefly larval densities by 77 % at peak infestation in all years. Remaining whitefly infestation under net was associated with the necessity of temporary net removal for the purpose of mechanical weeding, which caused primary whitefly infestation. Release of mass rearedE. tricolour under net at the first signs of larval infestation significantly increasedA. proletella-parasitation and reduced infestation compared to netted controls without release. Furthermore, at highest dosage in 2009,E. tricolor had a significant enhancing effect on raw yield and the quality level of marketable yield. Additional on-farm experiments without netting in 2008 and 2009 confirmed the control potential ofE. tricolor. Although the most important project mile stones have been achieved, namely (a)E. tricolour-establishment under net and in the open field, (b) enhanced parasitation corresponding with pest density decline and (c) a positive impact on yield and quality parameters, further research will be necessary. The focus should be on the initial infestation period, optimizing the timing, frequency and required dosage.  相似文献   

2.
Mountains are currently less affected by plant invasions than lowland ecosystems. Since 2005 the Mountain Invasion Research Network (MIREN, www.miren.ethz.ch) investigates the risk of plant invasions into mountains and develops preventive management strategies. A database of non-native and invasive plant species in mountains worldwide includes currently some 1500 species. Particularly problematic are woody species and ornamental plants that are often pre-adapted to a mountain climate. The risk of plant invasions in mountains is expected to increase in the near future. Climate change will enable the upward movement of lowland invaders into mountain ecosystems. Increased anthropogenic land use and disturbances and a shift of land use from grazing systems to tourism, which will lead to the introduction of new non-native plants, may further increase invasion risks. Mountains, and in particular the European Alps, are among the very few ecoregions in the world not yet badly affected by plant invasions. Managers have the unique opportunity to respond in time to an emerging threat. Preventive measures are the most effective and cost-efficient management option. Regulation of the transport of potentially invasive plant species should be a management priority. With climate change the upward movement of native lowland plants may also become a conservation concern. A broad discussion of the valuation and management of the change of mountain floras is needed. Besides plants other groups of organisms such as animal and plant pests may increasingly become a problem in mountains.  相似文献   

3.
Abstract In the frame of the investigation of epidemiology of soil-borne viruses, like the Soil-borne cereal mosaic virus (SBCMV), Soil-borne wheat mosaic virus (SBWMV) and the Bymovirus Wheat spindle streak mosaic virus (WSSMV), which were transmitted by fungal vector Polymyxa graminis Ledingham, the infection progress in different cereals was observed. The detection of furovirus and bymovirus in field plants was depending on temperature conditions during the vegetation period and the kind of cereals. The furoviruses tolerate a broad temperature spectrum and once established infection is detectable until the harvest time. In contrast to this observation, the propagation of WSSMV seems to be restricted to lower temperatures. Consequently, this virus is detected best at the end of February until the middle of April. Among the tested cereals, rye becomes more early infected than wheat and triticale. Both furoviruses could be differed by variable virulence reactions on cereal hosts and indicator plants. The SBCMV infects rye, triticale and wheat but not barley. The SBWMV is able to contaminate beside these cultures barley too. Both viruses are distinguished in the infection typ in Nicotiana benthamiana. Whereas SBCMV isolates spread out in the whole plant and cause yellowing and the die back of plants, the SBWMV infects the inoculated leaves only.  相似文献   

4.
Recently semi-dwarf oilseed rape varieties appeared in practical cropping. So far, only few studies about their properties in combination with weeds are available. Recently however an increasing number of weeds that are difficult to control are observed in oilseed rape. For the experiment Anchusa arvensis (L.) M.??Bieb., Sisymbrium officinale (L.) Scop. and a mixture of three different Geranium species were selected to study their development, seed and biomass production. Consequences for cropping on semi-dwarf oilseed rape cultivars were derived from the results. Three rape cultivars different in plant height were chosen for the experiments: the normal growing variety “Viking”, the semi-dwarf variety “PR45D01” and a full dwarf rape biotype for breeding purposes. In contrast oilseed rape with normal height, infestation of light-indigently and high growing weeds is more probable in semi-dwarf oilseed rape varieties. These weeds show increased biomass production and higher seed production per plant.  相似文献   

5.
Monitoring of the pathogen spectrum in grain peas (Pisum sativum L.) was conducted in Germany between 2005 and 2007. The outcome of this study implies that the infections of pathogens depend on the annual weather condition and the geographic area.Ascochyta pinodes, which infects aerial plant organs, was the pathogen found most frequently (on average 61, 8%). Especially in years with moist weather conditions a more severe spreading of the pathogen could be observed. Similarly, the occurrence ofBotrytis cinerea depends on the weather conditions. In 2007 were optimal conditions for infections and consequentlyB. cinerea was found with a high frequency of about 70%. Regarding diseases on root and stem base, this study clearly shows that infection of less prominent Fusarium species, such asF. redolens andF. avenaceum was significantly higher compared toF. oxysporum andF. solani.  相似文献   

6.
In the years 2013 and 2014 the presence and the infestation level of Plasmodiophora brassicae in six federal states of Germany were assessed using a bioassay method. Soils were sampled from 237 oilseed rape fields and the farmers provided information about the soil type, the soil pH values and the last year of oilseed rape cultivation. Clubroot was detected in 66 % of the fields investigated with a mean disease severity (BI) of 0.34. Between and within the federal states differences in presence and infestation level of P. brassicae were detected. In Schleswig-Holstein significantly more fields were infected by P. brassicae (90 %) and BI was relatively high (0.49) compared to Lower Saxony, Mecklenburg-Western Pomerania and North Rhine-Westphalia with 50 % infected fields and a mean BI of 0.27. Highly infested fields (BI > 0.8) were prevalent on 15 and 25 % of fields investigated in every federal state. Within the federal states the soil climate regions (BKR) differed significantly from each other. In BKR with light and sandy soils P. brassicae was less widespread compared to neighboring BKR with loamy soils. In addition, BKR with high infestation levels on fields investigated revealed a high presence of clubroot infested fields within this BKR. The infestation level in our study was significantly influenced by soil type, content of sand and soil pH value: soil types with a sand content of 30–35 % and a pH values lower than 5.6 showed high clubroot severity and disease incidences.  相似文献   

7.
Between 2000 and 2005 12 experiments with 18 herbicides were carried out in marigold in experimental stations and on marigold fields of Thuringian farms. The main objective of the tests was to get the necessary data for the authorization procedure according to the regulations of §?18 a PflSchG. Marigold plants are very susceptible against some herbicides Betanal Progress, Goltix Compact + ?l, Kontakt 320 SC, Lentagran WP und Stefes IPU. These herbicides and cause severe damages on this culture. The use oft the herbicides Bandur, BASTA and further herbicides with the active ingredient Glufosinat was authorized for the application in marigold according the regulations of §?18 a PflSchG in the past. The herbicides Devrinol FL, Fusilade MAX, Goltix 700 SC, Roundup UltraMAX und Targa Super can be used in artichoke according the regulations of §?18 b PflSchG. These herbicides aren??t enough for the chemical control of weeds likeEchinochloa spec.,Galinsoga spec., Polygonum spec. in marigold. In addition to the application of the herbicides mechanical measures are necessary.  相似文献   

8.
During 1991 to 1997 4078 samples sent in by public and private institutions were tested for their attack by arthropods. 5994 determinations were done. Seven the store damaging species of Lepidoptera were observed.Plodia interpunctella was the prime pest (305 determinations, mainly in cornflakes, muesli, sunflower seeds, nuts, feed, milk porredge and chocolate products). The percentage ofP. interpunctella increased from 4,3% (1991) to 5.6%–8.4% (for 1993). Larvae and adults and pure larvae samples ofP. interpunctella were mainly noticed from September to November. Pure adults samples could be counted for the most part from March to September. 27 the store damaging Coleoptera-species were determined.Stegobium paniceum was the prime pest (164 samples). 4% of the samples involvedS. paniceum. Further mainly observed beetle-species were:Lasioderma serricorne (36 samples),Tenebrio molitor (in 75 samples) andTrogoderma angustum (134 samples).
Aktualisierte Fassung des auf der Jahrestagung des Arbeitskreises Medizinische Arachno-Entomologie der Deutschen Gesellschaft für Allgemeine und Angewandte Entomologie (K?ln/ Monheim, 1 und 2. 10. 1997) gehaltenen Vortrages.  相似文献   

9.
Ancient Egyptian insect relics were accidentally enclosed in embalming resin which leaked from a priest's mummy and solidified on the floor of a wooden coffin from the end of the XVIIIth Dynasty (presumably 1323–1295 BC). The preserved insect relics were blowflies (Calliphoridae) recognized as Chrysomya marginalis or Chrysomya megacephala whose larvae had developed by feeding on the deceased's body prior to mummification as well as furniture beetles (Anobiidae) being either Oligomerus ptilinoides or Priobium carpini whose larvae had ingested the coniferous wood of the coffin. It is most likely that the human corpse and coffin were first attacked by the blowflies and furniture beetles prior to embalming, while infestation of the insect remains and textiles by Anthrenus sp. (Dermestidae) occurred in our time.  相似文献   

10.
For a compact growth of many potted plants you often have to use chemical growth inhibitors. Various species of herbs tend to an undesirable extension growth too. In general, the use of chemical inhibitors is prohibited in the production of potted herbs. For several years at the State Horticultural College and Research Institute Heidelberg there is employed an alternative method of mechanical stimulation treatment for a compact growth of potted plants. The greatest reduction of elongation was obtained, when the plants were treated with breaks in the early morning. In 2009 and 2010, the employees of the trial station proofed the effect of mechanical stimulation (Thigmomorfogenesis) to a large assortment of organically produced potted herbs. Green and red varieties of basil, parsley, coriander, chervil, lemon balm (2009) and four different varieties of mint (2010) were stimulated with a machine one week after beginning culture continuously 108 times per day. Compared to the untreated plants all mechanically stimulated herb species and varieties showed a tendency or significantly reduced elongation growth and therefore more stability. Depending on species and varieties the quality of these plants was visibly improved.  相似文献   

11.
Grapevine virus A (GVA) is associated with Kober stem grooving disease which belongs to the Rugose wood complex. The virus is frequently found in grapevine affected by leafroll but is not strictly associated with this disease. Probably the virus has a worldwide distribution – but very little information is available about the occurrence of GVA in Rhineland-Palatinate. The detection of GVA was conducted with indexing procedures using Kober 5BB as indicator and serological methods (ELISA). Indexing trials with infected material did not show any symptoms of Kober stem grooving two years after wooden grafting and five years after green grafting. The most suitable tissue to detect GVA serologically was petioles from mature leaves or cortical scrapings from dormant canes. In all experiments the tests with petioles resulted in much higher extinction values compared to the blades. About 46.9% of the 209 samples tested had an infection of GVA, 87.8% in mixed infections together with GLRaV-1 and 5.1% together with GLRaV-3. Only 7.1% of the tested plants were exclusively infected by GVA, none of the other ampelo- and closteroviruses could be detected. None of the GVA positively tested plants showed any symptoms of Rugose wood. The results indicated that the importance of a GVA infection on vines in Germany seems to be extremely low.  相似文献   

12.
Plant protection strategies are mostly assessed with respect to their efficacy and yield stability rather than their economic result. Therefore, this study aimed at evaluating the economic excellence of different strategies. Based on a long term field trial, the economics of four plant protection strategies in two different winter wheat quality classes (A wheat and E wheat) were evaluated. The field trial located in Dahnsdorf in Brandenburg comprised a crop rotation with six rotation components which is rather untypical for agricultural practice in that region. The economic analysis was based on field trial data from 13 years between 2004 and 2016 which was supplemented by secondary statistical data. Four plant protection strategies were considered: (S1) harrowing without chemical plant protection, (S2) plant protection in accordance to good farming practice taking into account the general principles of integrated pest management and a reduction of the treatment frequency index by (S3) 25% or rather (S4) 50% compared to good farming practice. By calculating the plant protection and labor cost free revenues for each year and strategy and by transferring these into annuities the four plant protection strategies were compared economically. The results for E wheat (elite wheat) were similar to those of A wheat (quality wheat) in terms of economic performance. A comparison of the plant protection strategies showed, that the abandonment of pesticides (S1) led to considerable economic disadvantages compared to the other three strategies. These three strategies which included the application of pesticides (S2, S3, S4) led to almost equivalent revenues, however, a reduction of the treatment frequency index by 25% compared to the good farming practice resulted in the best economical outcome for both wheat qualities. The applied crop rotation with six rotation components in combination with an intensive monitoring of the plant pests clearly supported the reduction of pesticide use in winter wheat without economic disadvantages. The results suggest, that such crop rotations have the potential to contribute to a sustainable crop production.  相似文献   

13.
Maize production trials carried out in eastern middle of Germany from 1999–2007 were used for statistical analysis of the optimum date for silage maize ripeness, quality and yield potential as well as choice of cultivar under drought conditions for silage and energy maize. The Silage maize Ripeness Index (the ratio of dry matter content of maize grains to dry matter content of stover) is more suitable for the determination of harvest date, yield maximum and silage maize quality as the dry matter content of the plant. The analysis is cheaper as well as not so material and time-consuming in comparison to the dry matter content of the silage maize of different hybrid maize populations and environments. Ensilage optimum and yield maximum correspond almost with the physiological ripeness of silage maize and are close to the grain dry matter content of 60 to 65%, to the dry matter content of stover under 24% and a ripeness index from 2,5 and higher. Only under these conditions it is possible to reach the optimal ripeness of 30 to 35% in the whole plant silage maize. In dependence on the Silage maize Ripeness Index (SRZ) parameters of silage and energy maize were created differential ripeness optimum, quality and yield potential. The aims of silage and energy maize are similar. The vitality of stover has a greater importance for energy maize. The Silage maize Ripeness Index (SRI) is, for whole plant maize, better than the Whole Plant Maize Ripeness Index (SRZ) for the choice of a hybrid in Germany. The dry matter content of grain in interaction with the dry matter of stover are better than dry matter content of the whole plant maize as ripeness indicator in the production of silage and energy maize for the harvesting time. SRI is also suitable for use as a standard in scientific trials and for better characteristic of cultivar types and environmental influence.  相似文献   

14.
Cover crops and under-sown crops have often been reported to have a positive impact on soil structure, soil living organisms and soil fertility. In many studies it was shown that they suppress weed populations. However, the percentage of winter annual cereals in European cropping system has strongly increased, which consequently reduced the time for growing cover crops. In this study, it was investigated if cover crops and under-sown have the capacity to reduce weed infestations also in rotations with a high percentage of winter annual cereals. Three field trials were conducted using at the University of Hohenheim from 2008 until 2010. Trifolium repens and Lolium perenne reduced weed density and weed biomass in Triticum aestivum and Triticum spelta, when they were sown as under-sown crops. Both under-sown crops had no negative effect on grain yield. Until 14 days after harvest, the under-sown crops developed a dense plant canopy. In the third experiment, Sinapis alba, Phacelia tanacetifolia, Avena strigosa and a mixture of Trifolium alexandrinum, Vicia sativa, Fagopyrum tataricum and Guizotia abyssinica were sown directly after harvest of winter wheat. Most of the cover crops emerged after few days and significantly reduced the density and biomass of emerging weeds. Sinapis alba resulted in a 93% reduction of above-ground weed biomass. Avena strigosa reduced root-biomass of weed by 97% and weed density by 90%. In order to achieve a significant weed suppression, cover crops need to emerged quickly and grow rapidly until the soil has been covered. The results of this study underline the potential of under-sown crops and cover-crops to support a sustainable and environmental friendly cropping system.  相似文献   

15.
Glyphosate is the most widely used herbicidal active ingredient in the world. In Germany, the distributed amounts have been doubled during the last ten years. There is public concern and criticism on this extensive use and use limitations are claimed. However, also loss of efficacy as reported from countries with high use intensity of glyphosate reduces long term use of these herbicides. Recently, scientific studies aimed to quantify the economic benefits of glyphosate to estimate the costs of losing or banning this herbicide. In this text, possibilities of reductions of glyphosate use in arable farming are discussed to obtain a necessary extent. It is pointed out, that those uses are preferential, that enable minimum soil cultivation that minimize soil erosion. Post-harvest applications have the potential for use reductions, due to replacement techniques such as soil cultivation that are available. Pre-harvest applications, which are targeted for crop maturation only, should not be used as a routine. It is suggested to seek for best management practices of glyphosate use.  相似文献   

16.
Early blight is a major disease of potatoes which has established in most potato growing areas as a destructive disease. The integration of several factors like weather conditions, nutrition, the use of potent fungicides as well as the cultivation of tolerant varieties are essential parts of an integrated control strategy and can be effective in preventing early blight disease. Cultivar resistance to early blight disease has become more important due to losses in fungicide sensitivity. Nevertheless, little research has been directed towards this area. Several, perennial field trials were carried out in order to investigate disease susceptibility for varieties out of different maturity groups. Early maturing varieties have shown to be more susceptible. The disease intensity (AUDPC) was much more expressed in early varieties contrary to medium and late maturing varieties. However, a stronger impact on potato yield has been found in the medium to late maturing varieties. We discuss the relevance of time and amount of leaf damage for formation of tuber yield.  相似文献   

17.
One year old rooted cuttings were fertilized with Osmocote exact according to 0,8 g N L? ? 1 substrate in February 2009. In August half of the plants received the same fertilizer dose while the other half was not refertilized. In autumn 2009 and in spring 2010 early resp. late frost tests were carried out under controlled conditions, furthermore sprouting was evaluated in spring 2010. Frost damage was measured with the electrolyte leakage method. In the early frost test biochemical stress responses like glucose, sucrose and proline were analyzed. In the new shoots N-, P-, and K-concentration were measured. Refertilized plants did not grow more but showed higher N-, P-, and K-concentrations. These plants had more proline in their buds and roots compared to the non-refertilized ones. Sucrose and glucose contents in the roots of refertilized plants were lower than in non-refertilized ones, in the buds there was no difference. Damage due to early frost was independent from refertilization for new shoots and buds but in roots higher for the refertilized plants. In spring 2010 refertilized plants sprouted earlier compared to non-refertilized ones. In buds damage due to late frost slightly increased in refertilized plants while in roots there was no difference between the fertilization treatments.  相似文献   

18.
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19.
Wheat insect pests and the beneficial arthropod populations were assessed using sweep net across a large scale winter wheat field in Bad Lausick (Free State of Saxony, Germany) before and after insecticide applications. The insecticides used were Karate (pyrethroid), Biscaya (neonicotinoid) and NeemAzal T/S (botanical insecticide). The tested compounds were sprayed twice during the early season growth stage (Elongation- GS 32) and at the heading stage (GS 55), and their effects were evaluated on wheat insect pests. The side effects of these insecticides on associated natural enemies were also studied. Monitoring was conducted for 4 weeks after each treatment. Cereal aphids, thrips, leafhoppers, cereal leaf beetles, cereal bugs and also many natural enemies such as predators (lady beetles, lacewings, syrphids, dance flies and spiders) and parasitoids (parasitic wasps) were surveyed. The dose of these insecticides resulted in reductions of wheat insect and natural enemy populations and this reduction was corrected based on Abbott equation. The results showed that Karate is correlated with the highest percentage reduction (79.5 %) to wheat insect pests. Karate use also resulted in a percentage reduction to natural enemies (30–60 %). Biscaya and NeemAzal T/S is correlated with an equivalent mortality percents (50–65 %) to wheat insect pests and resulted in a smaller percentage reduction of natural enemies (10–40 %) compared to Karate. Thrips and cereal bugs were more affected than leafhoppers. Lacewings and dance flies were more susceptible; while spider, syrphids and parasitoid wasps were more tolerant. Compatibility between natural insecticides and natural enemies is highly required to keep the environment clean.  相似文献   

20.
In the period from the beginning of grain cultivation in Central Europe until the middle of the last century, the number of arable weed species has steadily increased due to diverse and extensive cropping systems. Since 1950, crop production systems have been intensified, arable land has been used for development (construction), chemical and mechanical weed control has improved and many crops have disappeared. These factors all have contributed to a strong decrease of weed species diversity. Based on detailed vegetation assessments this pattern was confirmed in the Mehrstetten area (Reutlingen County). Sampling data from 2011 were compared to data available for the same sites from 1948/1949 and 1975–1978. In the period covered, weed diversity decreased from by 64 % (97 species). Abundance of weed species was significantly higher in the field margins as compared to the center of the fields. Vegetation data obtained in 2011 no longer allowed for the identification of plant species communities since no species distinctly characterizing certain communities were recorded. There was no shift in the Ellenberg, Zeigerwerte von Pflanzen in Mitteleuropa, 1991, indicator values. None of the 23 endangered species still present in 1948/49 was recorded in 2011. Based on survey results, we assume that decrease in weed species diversity was caused by intensive cropping practices associated with the use of mineral fertilizer and herbicides as well as other effective methods of weed control.  相似文献   

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