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1.
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   

2.
The cabbage root fly (Delia radicum) is a major pest of cruciferous crops in temperate regions of the world. A model using weather data has been developed to forecast the timing of D. radicum attacks. The model simulates development of a field population of D. radicum, commencing with the overwintering stage (diapause pupa) and following development through the first, second and, where appropriate, third generation until autumn. The model is based on a series of rate equations which describe the relationship between the rate of development of D. radicum and temperature. The model uses soil temperatures in the simulation of the development of the egg, larval and pupal stages, and air temperatures with the adult-fly stage, taking account of periods of summer dormancy (aestivation) and the onset of winter dormancy (diapause). Using local weather data or standard measurements of air and soil temperatures taken at agrometeorological stations, the model can forecast D. radicum activity in any region.  相似文献   

3.
Based on experimental data of oilseed rape monitoring in Schleswig-Holstein during the last seven years and actually established monitoring at four sites in Germany, a forecasting system for a determined autumn application against the important rape pathogen root collar (Phoma lingam; teleomorph: Leptosphaeria maculans) was developed. Early primary infections by ascospores in autumn are the elicitors of severe yield-reducing root collar epidemics, which depend on weather conditions, especially rainfall, leaf wetness and precipitation. Based on measured data and on trial weather records, a model was developed to predict the daily infection risk. Threshold values for a determined application were calculated based on disease incidence monitoring values. Applications predetermined from the calculated “daily infection value” reduced pathogen populations in autumn in comparison to the untreated control. Effects of the autumn treatments on root collar could be recorded; however, a significant yield effect occurred at one site only. Weather conditions over winter until vegetation start in the following year influence root collar severely. Due to this conclusion it is difficult to evaluate prosperous autumn treatments.  相似文献   

4.
During 1986–87 the presence of clubroot in soils sampled from 190 fields was assessed using a bioassay method, based on baiting the soils with Brassica campestris spp. pekinesis cv. Granaat. Clubroot was detected in 148 (72%) of the fields investigated and, on average, 49.2% of the plants were infected according to the bioassay. Subsequent testing of fields in 1990 and 1992 (54 and 81 fields, respectively) where no further Brassica crops had been grown indicated a significant decrease in the degree of infestation to 7.1% in 1992. Clay soils showed, on average, the highest degree of infestation, and high infestation was recorded for a wide range of pH values (5.2–6.6). The highest degree of infestation was recorded on fields where oilseeds were grown five times during the period 1965–85. The results presented show that, in a field with 100% infestation, the level of infestation declined to below the detection level after a period of 17.3 years. The half-life of the spore inoculum was determined to be 3.6 years. During the sensitivity testing of different Brassica species and cultivars, it was found that Chinese cabbage showed a low percentage of infestation in two soils, whilst some oilseed rape and spring oilseed turnip rape cultivars showed high degrees of infestation in these soils.  相似文献   

5.
Journal of Plant Diseases and Protection - Insecticide applications against the cabbage seedpod weevil, Ceutorhynchus obstrictus Marsham (Coleoptera: Curculionidae), in oilseed rape are conducted...  相似文献   

6.
Laboratory tests with carabid ground beetles found in Wellesbourne fields indicated that intermediate-sized beetles such asBembidion tetracolum, Amara familiar is andAgonwn dorsale were more effective predators of cabbage root fly (Erioischia brassicae) eggs than small beetles, e.g.Bembidion lampros andTrechus quadristriatus, or large beetles, e.g.Harpalus rufipes andPterostichus melanarius. Further tests indicated thatA. dorsale would be an ideal predator, as it can survive up to one month without food, is not killed byP. melanarius, aggregates naturally, and eats large numbers of cabbage root fly eggs/larva.A. dorsale is also relatively easy to retain near the stems of plants by simple barriers and is not cannibalistic. Unfortunately, sufficientA. dorsale were not available for greenhouse trials. Greenhouse trials withB. tetracolum indicated that two beetles per plant were sufficient to control the high levels of cabbage root fly infestation normally encountered in the field at Wellesbourne.  相似文献   

7.
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   

8.
Predicting the risk of weed infestation in winter oilseed rape crops   总被引：1，自引：0，他引：1  
Chemical weed control before crop and weed emergence is a systematic practice in winter oilseed rape crops in France. It would be profitable both for farmers and the environment to predict the level of weed infestation early on in the growing season and to control weeds only when necessary using post‐emergence weed control. The objective of this paper was to develop and evaluate simple models to predict weed biomass in oilseed rape crops. The model input variables were related to weed population characteristics and farmers’ practices. The models can be used to classify oilseed rape plots into two categories: plots with a level of weed infestation above a threshold or those with level of weed infestation below a threshold. A data set including 3 years of experiments, conducted across several regions in France, was used to estimate the parameters and to evaluate the models. High values of sensitivity and specificity were obtained when weed biomass was predicted as a function of sowing date, type of soil tillage, soil mineral nitrogen, crop density, weed density at emergence, and main characteristics of the most abundant weed species. Model performance strongly decreased when input variables related to the weed population were not taken into account. The best models correctly classified 90% of the plots with high weed infestation and 64% of the plots with low weed infestation.  相似文献   

9.
Phelipanche ramosa (Branched broomrape) is an obligate root parasitic plant that is a major pest of oilseed rape in France. Knowledge on seed viability and dormancy under field conditions is crucial to understand how to control P. ramosa, but is as yet unknown. Our study aimed to quantify these processes with a 2‐year seed burial experiment. Two genetically distinct populations of P. ramosa were studied, collected on winter oilseed rape (population O) and hemp (population H). Seed mortality was very low in both populations (4–7% per year). Although obligate parasitic seeds are assumed to germinate only after exposure to germination stimulants from host root exudates, a high proportion of population H seeds germinated spontaneously (up to 90%). Seeds of both populations displayed seasonal dormancy, with timing and magnitude depending on the population. Dormancy was low at the time each native host crop is usually sown. Populations differed in germination dynamics, with seeds of population H germinating faster. The difference in behaviour that we observed between populations is consistent with reported adaptations of pathovars to their preferred hosts. The results indicate that the parasitic plant management requires targeting at the populations concerned. For example, delayed sowing is more promising against population O than against population H.  相似文献   

10.
Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae) is a major pest of oilseed rape in Europe and North America. The last decade has seen growing interest in the occurrence, importance and efficiacy of its parasitoids as biocontrol agents. The infestation of pods by C. obstrictus larvae and their parasitism rates were assessed in a total of nine commercially-grown crops and fifteen experimental plots of winter oilseed rape in 2004–2007. Pod samples were collected at the pod maturation stage and incubated in emergence traps. Emerged larvae, their exit holes and parasitoids were counted and identified; the percentage of infested pods and parasitism rates were calculated. Pod infestation by larvae increased continuously over the study period. The parasitism level was lowest in 2005 and increased thereafter up to 96%. The most abundant parasitoid was Trichomalus perfectus (Walker), but Mesopolobus morys (Walker) and Stenomalina gracilis (Walker) (Hymenoptera: Pteromalidae) were also reared from host larvae. This study showed that naturally-occurring ectoparasitoids of C. obstrictus were capable of becoming established as viable populations and have the potential to contribute to biological control of C. obstrictus.  相似文献   

11.
The pollen beetle is the most important pest in Danish oilseed rape crops and it is essential that farmers are able to control this pest, especially in years when the economic damage threshold will be exceeded. About seven years ago, Danish oilseed rape growers began reporting that the pyrethroids seemed to be losing effectiveness towards pollen beetles. In 2001 18 populations collected from winter and spring oilseed rape fields were tested and very high level of insecticide resistance was found. In 2003 100 populations of pollen beetles were tested, using a FAO dip-test, for resistance to fenitrothion, lambda-cyhalothrin and tau-fluvalinate. It can be concluded that many Danish populations of pollen beetles are resistant to the pyrethroid lambda-cyhalothrin and to a lesser extent to the pyrethroid tau-fluvalinate. No resistance to the organophosphate fenitrothion was found.  相似文献   

12.
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   

13.
Pyrethroid resistant pollen beetles ( Meligethes aeneus ) are widely distributed in Germany and other European countries. Other insect pests on oilseed rape are also exposed to pyrethroids which often have more than one application per season. In spite of this scarce information about the sensitivity of other oilseed rape pest insects is available. To address this monitoring of pyrethroid sensitivity of different oilseed rape pest insects has been carried out since 2005. Laboratory experiments were conducted using an adult-vial-test design with samples collected in different areas of Germany.
Most samples of Ceutorhynchus napi , C. assimilis , C. pallidactylus , Dasineura brassicae , Phyllotreta spp. and Psylliodes chrysocephala tested from 2005–2007 showed 100% mortality at 0.003 and 0.015 µg/cm2 lambda-cyhalothrin used as reference test pyrethroid. Some samples especially of C. pallidactylus , C. napi and C. assimilis showed a lower mortality with alive and healthy beetles at 0.015 µg/cm2 lambda-cyhalothrin. For all samples tested from 2005–2007 100% mortality was found only at higher rates of 0.0375 or 0.075 µg/cm2 lambda-cyhalothrin.
To date, no clear pyrethroid resistance has been detected in other oil seed rape pest insect populations in Germany.  相似文献   

14.
In Israel, narcissus bulb flies (Diptera: Syrphidae) are serious pests of cultivated flower bulbs of the families Liliaceae and Amaryllidaceae. The large narcissus fly(Merodon eques) is the major pest, whereas the small narcissus fly (a new species in the genusEumerus, yet to be described) is only a secondary pest. The large narcissus fly is also considered a quarantine pest by the U.S.A. authorities. Narcissus bulbs,Narcissus tazetta (var. ‘Ziva’), were planted in an experimental field at Bizzaron during November 1995 and harvested during June 1996. Currently aldicarb (Temik) is recommended for the control of narcissus fly larvae. We compared the control efficacy of imidacloprid (Confidor) and isazofos (Miral) with that of aldicarb. These latter insecticides were applied to the soil in February, in April, or on both dates. The mean level of damaged bulbs in the untreated plots was 32%. Two applications of aldicarb, one in February and one in April, reduced the damage to the lowest level of 0.5%. A single application of aldicarb in February, and two applications of imidacloprid—one in February and one in April—reduced the damage to 5-10%. Treatments with imidacloprid in February or in April, reduced the damage to 12-13%. Neither one application of aldicarb in April, nor any of the treatments with isazofos, was effective. In all treatments, larvae of the large narcissus fly were found in only approximately one-third of the damaged bulbs. The level of infestation with the small narcissus fly in the untreated bulbs was only approximately 2%. The effects of the insecticide treatments on the small narcissus fly were similar to those recorded for the large narcissus fly .  相似文献   

15.
Pollen beetle, Meligethes aeneus F. (Coleoptera: Nitidulidae) is a major univoltine pest of oilseed rape in many European countries. Winter oilseed rape is cultivated on several million hectares in Europe and the continuous use of pyrethroid insecticides to control pollen beetle populations has resulted in high selection pressure and subsequent development of resistance. Resistance to pyrethroid insecticides in this pest is now widespread and the levels of resistance are often sufficient to result in field control failures at recommended application rates. Recently, metabolic resistance mediated by cytochrome P450 monooxygenases was implicated in the resistance of several pollen beetle populations from different European regions. Here, we have also investigated the possible occurrence of a target-site mechanism caused by modification of the pollen beetle para-type voltage-gated sodium channel gene. We detected a single nucleotide change that results in an amino acid substitution (L1014F) within the domain IIS6 region of the channel protein. The L1014F mutation, often termed kdr, has been found in several other insect pests and is known to confer moderate levels of resistance to pyrethroids. We developed a pyrosequencing-based diagnostic assay that can detect the L1014F mutation in individual beetles and tested more than 350 populations collected between 2006 and 2010 in 13 European countries. In the majority of populations tested the mutation was absent, and only samples from two countries, Denmark and Sweden, contained pollen beetles heterozygous or homozygous for the L1014F mutation. The mutation was first detected in a sample from Denmark collected in 2007 after reports of field failure using tau-fluvalinate, and has since been detected in 7 out of 11 samples from Denmark and 25 of 33 samples from Sweden. No super-kdr mutations (e.g. M918T) known to cause resistance to pyrethroids were detected. The implications of these results for resistance management strategies of pollen beetle populations in oilseed rape crops are discussed.  相似文献   

16.
This paper describes the consequences of the ban on neonicotinoid seed treatments on pest management in oilseed rape. Since the ban was implemented in December 2013, there have been serious crop losses in 2014, 2015 and 2016 owing to cabbage stem flea beetles, Psylliodes chrysocephala, and aphids, Myzus persicae, which have developed resistance to the alternative pyrethroid sprays that were employed to control them. This has resulted in increased crop losses, decreased yields and a substantial decrease in the area grown, leading to fewer flowering crops available in the spring, especially in the eastern region of the United Kingdom. This is likely to have an adverse effect on bees locally. © 2016 Society of Chemical Industry  相似文献   

17.
BACKGROUND: Pollen beetle (Meligethes spp.) is a major pest of European oilseed rape crops. Its resistance to pyrethroid insecticides has been recorded in samples of beetles collected in Europe since at least 1999, and problems with the control of the beetle in the field have been widely reported. In 2007, a Pollen Beetle Working Group was formed through the Insecticide Resistance Action Committee (IRAC) in order to coordinate efforts for surveying pyrethroid resistance development. RESULTS: The results of the first 3 years of the pollen beetle pyrethroid susceptibility survey using a laboratory test are presented in this paper. Resistant beetle samples were collected from 20 of the 21 countries surveyed, with a general trend of increasing frequency and spread of resistant samples in European oilseed‐rape‐growing regions. CONCLUSION: Pyrethroid‐resistant beetles dominate in Western and Central Europe and are becoming established in the North and East, the main oilseed‐rape‐growing areas of Europe. The development and spread of pyrethroid‐resistant pollen beetles highlights the need for effective management strategies for oilseed rape insect pests. Copyright © 2011 Society of Chemical Industry  相似文献   

18.
Data on weed species currently found in winter oilseed rape, the extent of their occurrence and regional distinctions were collected in autumn 2005 and 2006 from a total of 978 rape fields throughout Germany. Investigations took place on untreated sites at the six to eight leaf stage of rape. Weed frequencies and densities were determined by randomly placing a 0.1?m2 quadrate frame ten times in each plot, identifying and counting all plants within the frame. Two year results are presented here with a main focus on regional distinctions in total weed infestation, species richness as well as differences in frequencies and densities of selected weed species between the federal states. As expected, the majority of weed species occurring in winter oilseed rape is not evenly spread over Germany. On the on hand there are weeds with a more or less limited distribution which can be frequently found in some regions but are absent in others while on the other hand several ubiquitous weed species mainly show regional differences in their densities. Sisymbrium officinale, Descurainia sophia, Centaurea cyanus, Anchusa sp., Sonchus sp., Rumex sp. or Euphorbia sp. are some of the weed species of mostly regional importance. In contrast statistically proofed differences in weed densities in the federal states of Germany were recorded for Capsella bursa-pastoris, Chenopodium album, Galium aparine, Lamium sp., Matricaria sp., Stellaria media, Thlaspi arvense, Veronica sp. and Viola arvensis. Total weed infestation level and the mean number of species per site also differed between the federal states of Germany.  相似文献   

19.
The olive fruit fly, Bactrocera oleae (Rossi), is the major olive pest in the Mediterranean Basin, being responsible for high losses in olive production. The objective of this work was to study the influence of B. oleae infestation on the pomological parameters and nutritive value (lipids, proteins, carbohydrates and ash) of eight olive cultivars (Abani, Aellah, Blanquette de Guelma, Chemlal, Ferkani, Limli, Rougette de Mitidja and Souidi) from Algeria. The results displayed different degrees of susceptibility of the studied cultivars to this pest. Fruit size (weight) and the Fruit weight / stone weight ratio are significantly correlated with the attack. The statistical treatment of the results (PCA and HAC) highlighted different behaviors from the cultivars, concerning the attack. There are some cultivars more susceptible, being the nutritional value also affected. The lipid and protein contents were positively correlated with the attack and the carbohydrates negatively, suggesting a careful choice by the B. oleae. Ovipositional preference of olive fruit fly females and the success of larval development in different olive cultivars are crucial to establishing new approaches in Integrated Pest Management (IPM) against this pest.  相似文献   

20.
Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most important diseases of oilseed rape worldwide and leads to considerable yield losses. In this study, a non-specific lipid transfer protein-like antimicrobial protein gene (LJAMP2) from motherwort (Leonurus japonicus) was introduced into oilseed rape (Zhongyou 821) by Agrobacterium-mediated transformation. In vitro experiments revealed that the mycelial growth of S. sclerotiorum was significantly inhibited when supplied with crude leaf extracts from transgenic oilseed rape plants overexpressing LJAMP2. Furthermore, in vivo studies showed that transgenic LJAMP2 plants had enhanced resistance to S. sclerotiorum. Semi-quantitative RT-PCR analysis showed that the LJAMP2 gene was transcribed in all transformed plants. In addition, we also found that overexpression of LJAMP2 in transgenic plants caused constitutive activation of the defense-related gene PR-1 and an increase of H2O2 production, but did not enhance PDF1.2 expression. Our results suggest that constitutive expression of the LJAMP2 gene from motherwort seeds might be exploited to improve the resistance of oilseed rape against S. sclerotiorum.  相似文献   

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