Utskrift
UGRAS er planter som er uønsket. En slik definisjon betyr at samme art kan være ugress et sted, for eksempel i hveteåkeren, men ha pryd- eller nytteverdi i en annen sammenheng. FREMMEDE INVADERENDE PLANTER er uønska fordi de kan utgjøre risiko for hjemlige arter, naturmangfold eller kulturplantene våre.
Therese With Berge
Forsker
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Divisjon for bioteknologi og plantehelse
(+47) 922 93 927 therese.berge@nibio.no Kontorsted: Ås - Bygg H7
Ugras som er svært vanskelig å bekjempe, for eksempel floghavre (Avena fatua), er underlagt lovverk for å hindre spredning. En kan også definere kulturplanter (f.eks. oljevekster) som ugras hvis de dukker opp i en annen kultur (f.eks. kornåker) året etter og stjeler mye lys, vann og næring. Kveke (Elymus repens) er et av ugrasene som det er satt store ressurser inn på å bekjempe, men kveka kan faktisk være til hjelp hvis den sprer seg i en veiskråning og binder jorda, slik at erosjonsfaren reduseres. Man må se hvor, når og hvordan plantene opptrer for å kunne definere dem som ugras.
Nettside med nyttig og relevant informasjon om biologi og bekjempelse av planteskadegjørere (ugras, sykdommer og skadedyr). Du finner også informasjon om biologien til en del nyttedyr av plantevernbetydning.
Mer informasjon Til tjenestenVarsling innen planteskadegjørere
Mer informasjon Til tjenestenPlantevernguiden er en nettbasert tjeneste som gir deg en samlet oversikt over godkjente kjemiske og biologiske plantevernmidler. Tjenesten er utviklet i et samarbeid mellom Mattilsynet og NIBIO.
Mer informasjon Til tjenestenMany herbaceous perennial plant species gain significant competitive advantages from their underground creeping storage and proliferation organs (CR), making them more likely to become successful weeds or invasive plants. To develop efficient control methods against such invasive or weedy creeping perennial plants, it is necessary to identify when the dry weight minimum of their CR (CR DWmin) occurs. Moreover, it is of interest to determine how the timing of CR DWmin differs in species with different light requirements at different light levels. The CR DWmin of Aegopodium podagraria, Elymus repens and Sonchus arvensis were studied in climate chambers under two light levels (100 and 250 μmol m−2 s−1), and Reynoutria japonica, R. sachaliensis and R. × bohemica under one light level (250 μmol m−2 s−1). Under 250 μmol m−2 s−1, the CR DWmin occurred before one fully developed leaf in R. sachaliensis, around 1–2 leaves in A. podagraria and E. repens and around four leaves in S. arvensis, R. japonica and R. × bohemica. In addition to reducing growth in all species, less light resulted in a higher shoot mass fraction in E. repens and S. arvensis, but not A. podagraria; and it delayed the CR DWmin in E. repens, but not S. arvensis. Only 65% of planted A. podagragra rhizomes produced shoots. Beyond the CR DWmin, Reynoutria spp. reinvested in their old CR, while the other species primarily produced new CR. We conclude that A. podagraria, R. sachaliensis and E. repens are vulnerable to control efforts at an earlier developmental stage than S. arvensis, R. japonica and R. × bohemica.
I denne rapporten presenteres resultater fra biologisk veiledningsprøving av ugrasmidler i gras- og kløverfrøeng, vår- og høstkorn, åkerbønne, potet, blomkål, gulrot under plast og på friland, rotpersille og jordbær.
I denne rapporten presenteres resultater fra biologisk veiledningsprøving av ugrasmidler i grasfrøeng, vår- og høstkorn, potet, blomkål, gulrot under plast og på friland, pastinakk, rotpersille, bønne og jordbær, samt en test av avdriftreduserende dyser.
Ornamental jewelweed (Impatiens glandulifera Royle) is an alien invasive plant in Europe. This annual plant often grows in riparian habitats where herbicides are prohibited. Several studies have reported the negative effect on ecosystem and ecosystem services by this species. However, limited research is published on control measures and the aim of our study was to explore use of hot water and cutting to control I. glandulifera. A lab experiment showed that the lethal water temperature for seed was between 45 and 50 C. In a pot experiment with seeds in soil, emergence of I. glandulifera was reduced by 78% and 93% compared with the untreated control with volumes of hot water (80 C) of 7.2 and 14.5 L m−2, respectively. When treatments were conducted on relatively tall plants (almost 60 cm) in late June, hot water gave significantly better control than cutting. Compared with an untreated control, I. glandulifera cover was reduced by 97% and 79% after hot water and cutting, respectively. Application of hot water to smaller (<40 cm) and less developed plants (BBCH 12–13) in early June and cutting of plants with visible flower buds (mid-July) led to no significant difference in cover. Compared with an untreated control, I. glandulifera cover was reduced by 99% (cut below first node) and 91% (hot water and cut above first node). When relatively tall plants (almost 60 cm) were treated, hot water use was high (31.1 L m−2) and required twice as many work hours (4.8 min m−2) as cutting (2.4 min m−2). When smaller plants (<40 cm) were targeted, work hours and hot water use were reduced to 2.1 min m−2 and 13.7 L m−2, respectively.
Couch grass (Elymus repens) is a morphologically diverse, rhizomatous, perennial grass that is a problematic weed in a wide range of crops. It is generally controlled by glyphosate or intensive tillage in the intercrop period, or selective herbicides in non-susceptible crops. The aim of this review is to determine the efficacy of non-chemical strategies for E. repens control. The review shows that indirect control measures like crop choice, subsidiary crops, and fertilizer regimes influence E. repens abundance, but usually cannot control E. repens. Defoliation (e.g., mowing) can control E. repens growth, but efficacy varies between clones, seasons, and defoliation frequencies. Tillage in the intercrop period is still the main direct non-chemical control method for E. repens and its efficacy can be increased, and negative side-effects minimized by an appropriate tillage strategy. Some new tillage implements are on the market (Kvik-up type machines) or under development (root/rhizome cutters). Alternative methods that can kill E. repens rhizomes (e.g., steaming, soil solarization, biofumigation, hot water, flooding) often have high costs or time requirements. More studies on the effect of cropping system approaches on E. repens and other perennial weeds are needed.
Teff is a staple and well adapted crop in Ethiopia. Weed competition and control have major effects on yields and economic returns of the crop in the country. Among the weed management methods, development and use of weed competitive teff varieties remain the cheapest and most sustainable weed management option. Ten teff varieties were tested for their weed competitive ability in two locations. Treatments were applied using a split plot design with three blocks at each location for two consecutive seasons. Hand weeding and non-weeded treatments were applied to whole plot treatments with teff varieties assigned as split plots within the whole plot. The main objective was to determine relative competitive ability among teff varieties. Results showed that teff varieties showed significant variation in their weed competitive abilities. The varieties ‘Kora’ and ‘DZ-Cr-387’ significantly reduced weed density, dry weight, and cover more than the other teff varieties. They also had the lowest yield losses with a loss of 6% in biomass yield and 18% in grain yield recorded from ‘Kora’ and a loss of 17% in biomass yield and 21% in grain yield recorded from ‘DZ-Cr-387’. Therefore, they showed the highest weed competitive ability compared to the other varieties.
There is a need both in organic farming and on farms using integrated pest management for non-chemical measures that control the perennial weed flora. The effect of mechanical weeding and fertilisation on perennial weeds, fungal diseases and soil structure were evaluated in two different experiments in spring cereals. Experiment I included six strategies. The first strategy was (1) without specific measures against perennial weeds. The other strategies encompassed one or two seasonal control measures; (2) rhizome/root cutting with minimal soil disturbance in autumn, (3) hoeing with 24 cm row spacing, (4) combined hoeing and disc harrowing in autumn, (5) ‘KvikUp’ harrowing in spring, and (6) ‘KvikUp’ harrowing in spring and autumn. Experiment II included factor (i) inter-row hoeing and (ii) fertilisation level. This experiment included the comparison between normal row spacing (12 cm) with weed harrowing versus double row spacing (=24 cm) in combination with inter-row hoeing and 4 fertilisation levels (50–200 kg N ha−1). In experiment I the strategies consisting of no or one direct weed control measure (1, 2, 3 and 5) clearly did not control the perennial weeds. The two seasonal control measures (4 and 6) gave a satisfactory weed control and highest crop yield. The combination of best weed control and no measured harmful effects on soil structure or increase of fungal diseases may explain the highest yields for these strategies. In Experiment II, hoeing and 24 cm spacing gave less perennial biomass compared to 12 cm spacing. Grain yields increased linearly with increasing nitrogen input. The study shows that both inter-row hoeing and weed harrows, are important elements in integrated pest management practice and organic farming. In addition, our results indicate that efficient mechanical weeding is possible without harmful effects in crop rotation consisting of various spring cereals as regards soil structure and plant health.
Allelopathic potential of 10 teff varieties was assessed in laboratory experimentation (conducted in NIBIO, Norway), and determined with an agar-based bioassay using ryegrass and radish as model weeds. Field experiments were conducted in Tigray, Ethiopia during 2015 and 2016 to identify the most important agronomic traits of teff contributing to its weed competitive ability. A split plot design with three blocks was used considering hand weeding as the main plot and varieties as the subplot. Randomized complete block design (RCBD) with four blocks was used in the laboratory experiment. The highest potential allelopathic activity (PAA) and specific potential allelopathic activity (SPAA) were recorded from a local landrace with an average PAA value of 11.77% and SPAA value of 1.21%/mg respectively, when ryegrass was used as the model weed. ‘Boset’ had the highest average PAA value of 16.25% and an SPAA value of 1.53%/mg, when using radish as the model weed. The lowest PAA and SPAA values were recorded from ‘DZ-Cr-3870 when using ryegrass and radish as model weeds. Days to emergence, height, tiller no./plant, biomass yield, and PAA of the crop significantly contributed to the variance of the weed biomass, cover, and density. Hence, they were the most important agronomic traits enhancing the competitive ability of teff.
Resistens mot kjemiske plantevernmidler hos skadedyr, plantepatogene sopper og ugras er et alvorlig problem i flere matkulturer. Resistens oppstår som følge av for hyppig og ensidig bruk av plantevernmidler med samme biokjemiske virkemåte. Resistente skadegjørere kan også spre seg over landegrensene ved immigrasjon eller ved at de følger med importert plantemateriale. Vi har hatt mistanke om at immigrerende kålmøll og gråskimmel som følger med importerte småplanter av jordbær kan være resistente mot kjemiske plantevernmidler som brukes til å bekjempe disse skadegjørerne i Norge. I 2016 immigrerte store mengder kålmøll (Plutella xylostella) til Norge, og det ble påvist resistens mot insektmiddelet (insekticidet) lambda-cyhalotrin hos kålmøll-larver som ble samlet inn fra to kålfelt i Viken og Trøndelag. I 2019 var det en ny kålmøllinvasjon, og vi samlet inn og testet kålmøll-larver fra tre kålfelt i Rogaland og Viken. Larvene på alle de tre stedene var resistente mot lambda-cyhalotrin.
In autumn, agricultural perennial weeds prepare for winter and can store reserves into creeping roots or rhizomes. Little is known about influence of climate change in this period. We tested the effect of simulated climate change in autumn on three widespread and noxious perennial weeds, Elymus repens (L.) Gould, Cirsium arvense (L.) Scop. and Sonchus arvensis L. We divided and combined simulated climate change components into elevated CO2 concentration (525 ppm), elevated temperatures (+2–2.5°C), treatments in open‐top chambers. In addition, a control in the open‐top chamber without any increase in CO2 and temperature, and a field control outside the chambers were included. Two geographically different origins and three pre‐growth periods prior to the exposure to climate change factors were included for each species. All species increased leaf area under elevated temperature, close to doubling in E. repens and quadrupling in the dicot species. E. repens kept leaves green later in autumn. C. arvense did not benefit in below‐ground growth from more leaf area or leaf dry mass. S. arvensis had low levels of leaf area throughout the experiment and withered earlier than the two other species. Below‐ground plant parts of S. arvensis were significantly increased by elevated temperature. Except for root:shoot ratio of C. arvense, the effects of pure elevated CO2 were not significant for any variables compared to the open‐top chamber control. There was an additive, but no synergistic, effect of enhanced temperature and CO2. The length of pre‐growth period was highly important for autumn plant growth, while origin had minor effect. We conclude that the small transfer of enhanced above‐ground growth into below‐ground growth under climate change in autumn does not favour creeping perennial plants per se, but more leaf area may offer more plant biomass to be tackled by chemical or physical weed control.
I denne rapporten presenteres resultater fra biologisk veiledningsprøving av ugrasmidler i grasmark, grasfrøeng, vår- og høstkorn, gulrot under plast og på friland, pastinakk, rotpersille og bønne.
Reducing soil tillage can lead to many benefits, but this practice often increases weed abundance and thus the need for herbicides, especially during the transition phase from inversion tillage to non-inversion tillage. We evaluated if subsidiary crops (SCs, e.g., cover crops) can mitigate the effects of non-inversion tillage on weed abundance. Two-year experiments studying SC use, tillage intensity, and nitrogen (N) fertilization level were carried out twice at six sites throughout northern and central Europe. SCs significantly reduced weed cover throughout the intercrop period (−55% to −1% depending on site), but only slightly during the main crops. Overall weed abundance and weed biomass were higher when using non-inversion tillage with SCs compared to inversion tillage without SCs. The effects differed due to site-specific weed pressure and management. With increasing weed pressure, the effect of SCs decreased, and the advantage of inversion over non-inversion tillage increased. N fertilization level did not affect weed abundance. The results suggest that SCs can contribute by controlling weeds but cannot fully compensate for reduced weed control of non-inversion tillage in the transition phase. Using non-inversion tillage together with SCs is primarily recommended in low weed pressure environments.
The abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) has increased in coastal grasslands in Norway over recent decades, and their spread has coincided with increased precipitation in the region. Especially in water‐saturated, peaty soils, it appears from field observations that productive grasses cannot compete effectively with such rapidly growing rush plants. In autumn–winters of 2012–2013 and 2013–2014, a four‐factor, randomised block greenhouse experiment was performed to investigate the effect of different soil moisture regimes and organic matter contents on competition between these rush species and smooth meadow‐grass (Poa pratensis). The rush species were grown in monoculture and in competition with the meadow‐grass, using the equivalent of full and half the recommended seed rate for the latter. After about three months, above‐ and below‐ground dry matter was measured. J. effusus had more vigorous growth, producing on average 23–40% greater biomass in both fractions than J. conglomeratus. The competitive ability of both rush species declined with decreasing soil moisture; at the lowest levels of soil moisture, growth reductions were up to 93% in J. conglomeratus and 74% in J. effusus. Increasing water level in peat–sand mixture decreased competivitiveness of meadow‐grass, while pure peat, when moist, completely impeded its below‐ground development. These results show that control of rush plants through management may only be achieved if basic soil limitations have been resolved.
Tillage controls perennial weeds, such as Elymus repens, partly because it fragments their underground storage organs. However, tillage is difficult to combine with a growing crop, which limits its application. The aim of this study was to evaluate how soil vertical cutting with minimum soil disturbance and mowing affect the growth and competitive ability of E. repens in a grass–clover crop. A tractor-drawn prototype with vertical disks was used to fragment E. repens rhizomes with minimal soil and crop disturbance. In experiments performed in 2014 and 2015 at a field site close to Uppsala, Sweden, the rhizomes were fragmented before crop sowing (ERF), during crop growth (LRF), or both (ERFCLRF). Fragmentation was combined with repeated mowing (yes/no) and four companion crop treatments (none, Italian ryegrass, white clover, and grass/clover mixture). The results showed that in the grass–clover crop, rhizome fragmentation reduced E. repens rhizome biomass production and increased Italian ryegrass shoot biomass. ERF and LRF both reduced E. repens rhizome biomass by about 38% compared with the control, while ERFCLRF reduced it by 63%. Italian ryegrass shoot biomass was increased by 78% by ERF, 170% by LRF and 200% by ERFCLRF. Repeated mowing throughout the experiment reduced E. repens rhizome biomass by about 75%. Combining repeated mowing with rhizome fragmentation did not significantly increase the control effect compared to mowing alone. We concluded that rhizome fragmentation using vertical disks can be used both before sowing and during crop growth to enhance the controlling effect of grass–clover crops on E. repens.
Glyfosat er det mest brukte plantevernmidlet i Norge og på verdensbasis. Det har i de siste årene vært diskutert om dette ugrasmiddelet skulle få fornyet godkjenning. I 2017 ble glyfosat godkjent for fem nye år til 2022. Dersom glyfosat fases ut er en redd det vil få store negative konsekvenser for jordbruk og matproduksjon. Glyfosat brukes til å bekjempe ugras og andre uønska planter på dyrka og udyrka arealer. I jordbruket er glyfosat spesielt viktig for å begrense ugrasets avlingsreduserende effekt. I norsk jordbruk brukes glyfosat hovedsakelig til å bekjempe ugrasarten kveke i korndominerte omløp og ved fornying av grasmark. Ved redusert jordarbeiding er glyfosat viktig for bekjemping av flerårige og andre overvintrende ugras. Vi har i denne rapporten kartlagt kunnskap relevante for norske forhold på hvilke ikke-kjemiske og kjemiske alternativer til glyfosat som en har/kan få i framtida i korn og grasmark slik at matproduksjonen kan opprettholdes. Mekaniske tiltak som pløying og ulike former for jordarbeiding i stubben mot kveke og andre ugras, og radrensing i korn mot ugras generelt er viktige alternativer til glyfosat. Det er også noen nye redskapstyper (rotskjærere) som virker lovende i bekjemping av ugras. Videre så vil en god jord- og plantekultur med et godt vekstskifte bidra til å holde ugraset under kontroll. Per i dag fins det noen få kjemiske alternativer mot kveke i hvete, rughvete og rug og mot tofrøblada rotugras i korn. Det er andre kjemiske alternativer som kan undersøkes mer for bruk i stubbåker/til brakking av grasmark som for eksempel ulike organiske syrer og grasugrasmidler for tofrøblada kulturer........
Docks (Rumex spp.) are a considerable problem in grassland production worldwide. We investigated how different cultural management techniques affected dock populations during grassland renewal: (I) renewal time, (II) companion crop, (III) false seedbed, (IV) taproot cutting (V), plough skimmer and (VI) ploughing depth. Three factorial split-split plot experiments were carried out in Norway in 2007–2008 (three locations), 2008–2009 (one location) and 2009 (one location). After grassland renewal, more dock plants emerged from seeds than from roots. Summer renewal resulted in more dock seed and root plants than spring renewal. Adding a spring barley companion crop to the grassland crop often reduced dock density and biomass. A false seedbed resulted in 71% fewer dock seed plants following summer renewal, but tended to increase the number of dock plants after spring renewal. In some instances, taproot cutting resulted in less dock biomass, but the effect was weak and inconsistent, and if ploughing was shallow (16 cm) or omitted, it instead increased dock root plant emergence. Fewer root plants emerged after deep ploughing (24 cm) compared to shallow ploughing, and a plough skimmer tended to reduce the number further. We conclude that a competitive companion crop can assist in controlling both dock seed and root plants, but it is more important that the renewal time is favourable to the main crop. Taproot cutting in conjunction with ploughing is not an effective way to reduce dock root plants, but ploughing is more effective if it is deep and a skimmer is used.
Increasing abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) in pastures and meadows in western Norway has caused reductions in forage yield and quality in recent decades. Understanding plant development and regrowth following cutting is essential in devising cost-effective means to control rushes. In a field experiment in western Norway, we investigated development of above- and below-ground fractions of rush from seedlings to three-year-old plants, including the impact on vigour of disturbing growth by different cutting frequencies during the period 2009–2012. Each year, the plants were exposed to one or two annual cuts or left untreated and five destructive samplings were performed from March to early December. Juncus effusus showed significantly more vigorous growth than Juncus conglomeratus in the last two years of the study period. The above-ground:below-ground biomass ratio of both species increased mainly in spring and early summer and was reduced in late summer and autumn. Removal of aerial shoots also reduced the below-ground fraction of both species. One annual cut in July effectively reduced biomass production in both species by 30–82%, which was only a slightly smaller reduction than with two annual cuts, in June and August. Mechanical control measures such as cutting can thus effectively reduce rush vigour when performed late in the growing season.
Quackgrass is a problematic agricultural weed in the temperate zones of the world and is difficult to control without herbicides or intensive tillage. However, it may be possible to control quackgrass with less environmental impact by combining multiple low-intensity control methods. A pot experiment was conducted in July to October 2012 and repeated in June to September 2013 to investigate the effect of rhizome fragmentation, competition from white clover, shoot-cutting frequency, and cutting height on quackgrass. Rhizome fragmentation was expected to result in more, but weaker, quackgrass shoots that would be more vulnerable to shoot cutting and competition. However, by 20 d past planting, rhizome fragmentation did not change the total number of quackgrass shoots per pot, because an increase in main shoots was offset by a decrease in tiller numbers. Rhizome fragmentation did not reduce quackgrass biomass acquisition during the experimental period. Although rhizome fragmentation did reduce total fructan content, it did not enhance the effect of clover competition, shoot-cutting frequency, or shoot-cutting height. Clover competition by itself reduced quackgrass shoot numbers by 72%, rhizome biomass by 81%, and belowground fructan concentration by 10 percentage points, compared with no competition. The more frequently quackgrass shoots were cut, the less biomass quackgrass acquired, and a high shoot-cutting frequency (each time quackgrass reached 2 leaves) resulted in a lower belowground fructan concentration than a low shoot-cutting frequency (at 8 leaves). However, in pots without competition, a higher shoot-cutting frequency resulted in more quackgrass shoots. A lower shoot-cutting height (25 mm) had more impact when shoot cutting was more frequent. In conclusion, rhizome fragmentation did not reduce the number of quackgrass shoots or rhizome biomass, but competition from white clover, a high shoot-cutting frequency, and a low shoot-cutting height strongly suppressed quackgrass biomass and fructan acquisition.
Control of perennial weeds, such as Elymus repens, generally requires herbicides or intensive tillage. Alternative methods, such as mowing and competition from subsidiary crops, provide less efficient control. Fragmenting the rhizomes, with minimal soil disturbance and damage to the main crop, could potentially increase the efficacy and consistency of such control methods. This study's aim was to investigate whether fragmenting the rhizomes and mowing enhance the control of E. repens in a white clover sward. Six field experiments were conducted in 2012 and 2013 in Uppsala, Sweden, and Ås, Norway. The effect of cutting slits in the soil using a flat spade in a 10 × 10 cm or 20 × 20 cm grid and the effect of repeated mowing were investigated. Treatments were performed either during summer in a spring-sown white clover sward (three experiments) or during autumn, post-cereal harvest, in an under-sown white clover sward (three experiments). When performed in autumn, rhizome fragmentation and mowing reduced E. repens shoot biomass, but not rhizome biomass or shoot number. In contrast, when performed in early summer, rhizome fragmentation also reduced the E. repens rhizome biomass by up to 60%, and repeated mowing reduced it by up to 95%. The combination of the two factors appeared to be additive. Seasonal differences in treatment effects may be due to rhizomes having fewer stored resources in spring than in early autumn. We conclude that rhizome fragmentation in a growing white clover sward could reduce the amount of E. repens rhizomes and that repeated mowing is an effective control method, but that great seasonal variation exists.
Background and Aims Competitive crops are a central component of resource-efficient weed control, especially for problematic perennial weeds such as Elymus repens. Competition not only reduces total weed biomass, but denial of resources can also change the allocation pattern – potentially away from the underground storage organs that make perennial weeds difficult to control. Thus, the competition mode of crops may be an important component in the design of resource-efficient cropping systems. Our aim was to determine how competition from companion crops with different modes of competition affect E. repens biomass acquisition and allocation and discuss that in relation to how E. repens responds to different levels of light and nutrient supply. Methods Greenhouse experiments were conducted with E. repens growing in interspecific competition with increasing density of perennial ryegrass or red clover, or growing at three levels of both light and nutrient supply. Key ResultsElymus repens total biomass decreased with increasing biomass of the companion crop and the rate of decrease was higher with red clover than with perennial ryegrass, particularly for E. repens rhizome biomass. A reduced nutrient supply shifted E. repens allocation towards below-ground biomass while a reduced light supply shifted it towards shoot biomass. Red clover caused no change in E. repens allocation pattern, while ryegrass mostly shifted the allocation towards below-ground biomass, but the change was not correlated with ryegrass biomass. Conclusions The companion crop mode of competition influences both the suppression rate of E. repens biomass acquisition and the likelihood of shifts in E. repens biomass allocation.
Det er per i dag påvist resistens eller nedsatt følsomhet mot kjemiske plantevernmidler hos flere skadedyr, plantepatogener og ugras i norske jord- og hagebrukskulturer. Hos skadedyr er resistens mot pyretroider og nedsatt følsomhet for tiakloprid vanlig hos rapsglansbille i oljevekster. Resistens mot pyretroider er påvist hos ferskenbladlus og potetsikade fra potet, gulrotsuger fra gulrot, ferskenbladlus fra persille, kålmøll og ferskenbladlus fra kålvekster, jordbærsnutebille fra jordbær, og ferskenbladlus, bomullsmellus, veksthusmellus og sør-amerikansk minerflue fra veksthus. Det er også funnet resistens mot pirimikarb hos ferskenbladlus og nedsatt følsomhet for imidakloprid hos ferskenbladlus og bomullsmellus. I jordbær og bringebær er det indikasjoner på begynnende resistensutvikling mot flere av middmidlene. Hos plantepatogener er resistens mot QoI-fungicider påvist hos gråskimmel fra jordbær, bringebær og gran i skogplanteskoler, hos mjøldoggsopper i jordbær og veksthusagurk, og hos bladflekksopper i hvete. Resistens mot triazoler er funnet i flere bladflekksopper i hvete. Resistens mot hydroksyanilid- og SDHI-er utbredt hos gråskimmel fra jordbær og bringebær, og i skogplanteskoler er det påvist resistens mot tiofanater.....
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Knowledge about the reproduction strategies of invasive species is fundamental for effective control. The invasive Fallopia taxa (Japanese knotweed s.l.) reproduce mainly clonally in Europe, and preventing spread of vegetative fragments is the most important control measure. However, high levels of genetic variation within the hybrid F. × bohemica indicate that hybridization and seed dispersal could be important. In Norway in northern Europe, it is assumed that these taxa do not reproduce sexually due to low temperatures in the autumn when the plants are flowering. The main objective of this study was to examine the genetic variation of invasive Fallopia taxa in selected areas in Norway in order to evaluate whether the taxa may reproduce by seeds in their most northerly distribution range in Europe. Fallopia stands from different localities in Norway were analyzed with respect to prevalence of taxa, and genetic variation within and between taxa was studied using amplified fragment length polymorphism (AFLP). Taxonomic identification based on morphology corresponded with identification based on simple sequence repeats (SSR) and DNA ploidy levels (8× F. japonica, 6× F. × bohemica and 4× F. sachalinensis). No genetic variation within F. japonica was detected. All F. × bohemica samples belonged to a single AFLP genotype, but one sample had a different SSR genotype. Two SSR genotypes of F. sachalinensis were also detected. Extremely low genetic variation within the invasive Fallopia taxa indicates that these taxa do not reproduce sexually in the region, suggesting that control efforts can be focused on preventing clonal spread. Climate warming may increase sexual reproduction of invasive Fallopia taxa in northern regions. The hermaphrodite F. × bohemica is a potential pollen source for the male-sterile parental species. Targeted eradication of the hybrid can therefore reduce the risk of increased sexual reproduction under future warmer climate.
I denne rapporten presenteres resultater fra biologisk veiledningsprøving av ugrasmidler i grasmark, engsvingelfrøeng, vår- og høstkorn, såløk, gulrot under plast og på friland, knollselleri, pastinakk, rotpersille og bønne.
During the past two decades, significant spread of the perennial weeds Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) in coastal parts of Norway seems to have coincided with an observed rise in winter temperatures. This study investigated the frost tolerance (LT50) and effects of moderate frost exposure on rush plant regrowth over time during the period late November to late winter/spring, and photosynthetic activity in late winter/spring. Juncus effusus and J. conglomeratus of physiologically young age (seedlings) displayed similar high frost tolerance (LT50) and did not differ significantly in regenerative ability following prolonged frost exposure. Regrowth capacity generally increased during winter and when stress conditions increased, shoot formation was prioritised over total biomass production. Maximum quantum efficiency of photosystem II (Fv/Fm) and performance index of photosystem II (PI) were high in late winter/spring, with J. effusus showing higher values than J. conglomeratus. Green, photosynthetically active shoots, which facilitate accumulation of carbohydrates during autumn and even in winter, may provide Juncus spp. with substantial competitiveness in late winter and spring. The results revealed that the dominance of J. effusus over J. conglomeratus in pastures and leys is not due to major differences in winter survival parameters, but probably the higher photosynthetic efficiency observed in J. effusus. Generally higher temperatures during winter and lower frost kill may be contributing to the current increase in rush infestation.
Creeping perennial weeds are of major concern in organically grown cereals. In the present study, the effects of different timing of mouldboard ploughing with or without a preceding stubble cultivation period, on weeds and spring cereals were studied. The experiments were conducted at two sites in Norway during a two and three-year period, respectively, with the treatments repeated on the same plots. The soil cultivation treatments were a stubble disc-harrowing cultivation period followed by mouldboard ploughing and only mouldboard ploughing. The timing of the treatments were autumn or spring. The density and biomass of the aboveground shoots of Cirsium arvense (L.) Scop., Elymus repens (L.) Gould, Sonchus arvensis L. and Stachys palustris L. as well as the total aboveground biomass of the spring cereal crop (oats) were assessed. The control efficiency of C. arvense and S. arvensis was closely related to timing of the cultivation treatments. Cultivation in spring decreased the population of C. arvense and S. arvensis compared to autumn cultivation. For E. repens, timing of the treatments had no significant effect: the important factor was whether stubble cultivation was carried out (best control) or not. The overall best strategy for controlling the present perennial weed population was stubble cultivation followed by ploughing in spring. However, the associated relative late sowing of the spring cereal crop and lowered crop biomass, were important drawbacks.
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Seed biology is important for emergence in the field and for future weed infestations. This chapter focuses on seed biology, germination, dormancy and efforts in predicting weed emergence from seeds from a European perspective. It presents a brief overview of population dynamics in time and space, the factors influencing the dynamics and how population dynamics can be modelled. Emergence from the seed-bank starts with germination, pre-emergence growth and finally emergence. In addition to seeds, vegetatively propagated material is briefly mentioned. Dormancy influences under what conditions that germination can occur and regulates timing of germination. Population dynamics are important for understanding the whole system and are often based on the life-cycle of weeds: seed-bank, seedlings, adult plants, seed production and dispersal. Challenges in modelling emergence and population dynamics are large, due to differences between and within populations of species, variability in species response and there being many weed species in the same field with contrasting characteristics.
Without herbicides, the control of Elymus repens relies on intensive tillage, often in the form of repeated post-harvest stubble cultivations followed by ploughing. This is costly and time-consuming and also increases the risk of nitrogen leaching. Our aim was to quantify the controlling effect on E. repens of single and repeated cultivation and differing time of cultivation in relation to spring cereal harvest. A 2-year experiment was conducted at two sites in the south and east of Sweden in 2011–2012 and 2012–2013. We compared no, single and repeated tine cultivation followed by mouldboard ploughing; the single cultivation was performed directly after harvest or 20 days after harvest; when repeated, the first cultivation was performed immediately or 5 days after harvest, followed by a second cultivation 20 days after harvest. Tine cultivation in combination with mouldboard ploughing resulted in 50–70% lower rhizome biomass, and increased average subsequent cereal yields by 0–130% compared with ploughing alone. Large E. repens populations appeared to be more efficiently reduced by tine cultivation than smaller populations. A single tine cultivation 20 days after harvest tended to result in a higher E. repens shoot density and more rhizome biomass in the subsequent year than tine cultivation directly after harvest. Additional cultivation 20 days after harvest did not improve control of E. repens or the subsequent cereal grain yield, compared with a single cultivation conducted directly after harvest. In conclusion, preventing the growth of E. repens during the early part of the post-harvest autumn period was more important than starving rhizomes with repeated cultivations.
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Four field trials (spring wheat and oats) were conducted (one on clay soil, one on loam soil and two on silt soil) for three years in important cereal growing districts, to investigate the influence of tillage regimes (ploughing versus reduced tillage in either autumn or spring) and straw management (removed and retained) on plant residue amounts, weed populations, soil structural parameters and cereal yields. The effect of tillage on soil structure varied, mainly due to the short trial period. In general, the amount of small soil aggregates increased with tillage intensity. Reduced soil tillage, and in some cases spring ploughing, gave significantly higher aggregate stability than autumn ploughing, thus providing protection against erosion. However, decreasing tillage intensity increased the amounts of weeds, particularly of Poa annua on silt soil. Straw treatment only slightly affected yields, while effects of tillage varied between both year and location. Reduced tillage, compared to ploughing, gave only small yield differences on loam soil, while it was superior on clay soil and inferior on silt soil. Our results suggest that shallow spring ploughing is a good alternative to autumn ploughing, since it gave comparable yields, better protection against erosion and was nearly as effective against weeds.
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Two potential control methods for Elymus repens, which do not disturb the soil, are post-harvest mowing and competition from under-sown cover crops. Our aim was to quantify the effect of cover crop competition and mowing on E. repens and to evaluate the potential for combining the two methods. We present a two-factorial split-plot experiment conducted at three locations in Sweden, in two experimental rounds conducted in 2011–2012 and 2012–2013. A spring cereal crop was under-sown with perennial ryegrass, red clover or a mixture of the two (subplots). Under-sown crops were either not mowed, or mowed once or twice post-harvest (main plots). This was followed by ploughing and a new spring cereal crop the next year. Mowing twice reduced autumn shoot biomass by up to 66% for E. repens and 50% for cover crops compared with the control, twice as much as mowing once. Pure ryegrass and mixture treatments reduced E. repens shoot biomass by up to 40% compared with the control. Mowing twice reduced rhizome biomass in the subsequent year by 35% compared with the control, while the pure red clover treatment increased it by 20–30%. Mowing twice and treatments including red clover resulted in higher subsequent grain yields. We concluded that repeated mowing has the potential to control E. repens, but a low-yielding cover crop has insufficient effect on rhizome biomass. Clover–grass mixtures are of interest as cover crops, because they have the potential to increase subsequent crop yield and even at low levels they reduce E. repens above-ground autumn growth.
Methods for control of couch grass (Elymus repens L.) with reduced tillage and cover crops to achieve low risk of nitrogen (N) and phosphorus (P) leaching were investigated. Treatments with reduced post-harvest tillage (one or two passes with duckfoot cultivator), hoeing between rows in combination with a cover crop, and a cover crop mown twice during autumn were compared with treatments with conventional disc cultivation and the control without tillage or cover crop. The study was conducted on a sandy soil in Sweden with measurements of N and P leaching. A 2-year experimental protocol was used, repeated twice. Treatments were implemented in the first year, and effects on couch grass (shoot density, shoot and rhizome biomass) were measured during autumn and in the second year. Significant effects of a single duckfoot cultivation and cover crop strategies were observed on couch grass shoot density in autumn but persistent effects were not verified. In conclusion, a single cultivation after harvest instead of repeated reduced the risk of N leaching and a cover crop in combination with hoeing or mowing effectively reduced it. Repeated cultivations resulted in mean annual N leaching of 26 kg N ha−1 compared with 20 kg in the treatment with one cultivation, 17 kg in the control, 16 and 12 kg in cover crop treatments with mowing and hoeing, respectively. The P leaching was small (0.04–0.09 P ha−1 year−1), but there were indications of increased P drainage water concentrations in the treatment with a cover crop which was mown.
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Elymus repens is a perennial grass weed that causes great yield losses in a variety of crops in the southern and northern temperate zones. Primary control methods for E. repens are herbicides or intensive tillage, both of which have a number of negative side-effects, e.g. herbicides can contaminate groundwater, and tillage can cause increased nitrogen leaching. The aim of this thesis was to investigate how to make non- herbicide control of Elymus repens more resource efficient in terms of less energy demanding soil cultivation and reduced nitrogen leaching. Three field experiments were used to test cover crop competition, mowing and different types of optimised tillage techniques and timing, as well as the combination of under-sown cover crops and mowing or row hoeing. The growth, biomass allocation and morphological responses of E. repens to competition were studied in a greenhouse experiment. The effect of competition from under-sown cover crops on E. repens seems to depend greatly on the cover crop biomass achieved. At high biomass levels, the cover crop can be highly suppressive (Paper IV) and reduce nitrogen leaching (Paper III), while at low levels they can still provide benefits such as reduced E. repens shoot biomass and increased subsequent cereal yield (Paper I). However, a low-yielding red clover cover crop increased E. repens rhizome production by 20-30%. Under-sown cover crops were successfully combined with both mowing and row hoeing (Paper I & III), but while repeated mowing reduced E. repens rhizome production by 35% it could not be shown to give a competitive advantage to the cover crops over E. repens (Paper I). However, the low nitrogen leaching and reduced downward transport of nitrogen when mowing or row hoeing was combined with under-sown cover crops make them interesting control methods for future research. Delaying tine cultivation by a few days after harvest did not reduce E. repens control, but a delay by 20 days tended to result in higher E. repens rhizome biomass and shoot densities, compared to performing it within a few days of harvest. Repeated tine cultivation did not improve control of E. repens or increase subsequent cereal yield, compared to a single cultivation directly after harvest. Repeated cultivation during autumn should therefore not be used categorically, but only when there is reason to believe the shoots will pass the compensation point due to the autumn conditions. We conclude that a site specific approach is necessary to achieve resource efficient control of E. repens.
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Comparison of biology and mangement of mugwort (Artemisia vulgaris) between North America and Europe. Sammenlikning av biologi og bekjemping av burot (Artemisia vulgaris) mellom Nord-Amerika og Europa.
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Sammenlikning av biologi og bekjemping av burot (Artemisia vulgaris) mellom Nord-Amerika og Europa.
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Burot (Artemisia vulgaris) har de siste årene spredt seg raskt og er til stor sjenanse for mange. Ikke bare er den et plagsomt ugras, men den utgjør også et helsemessig problem. Norges Astma- og Allergiforbund (NAAF) regner med at 200.000 mennesker er allergiske mot burotpollen. Pollenet spres med vinden, men i et lavt luftsjikt og sjelden lengre enn 100-200 meter. Det vil derfor være effektivt å bekjempe burot lokalt, for å begrense allergiproblemer knyttet til burot nær barnehager, skoler, idrettsanlegg, boligområder og helseinstitusjoner.
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The success of weed management aimed at depleting the regenerative structures of perennial weeds depends largely on the sprouting activity of rhizome and root buds. Seasonal variation in sprouting of these buds on Cirsium arvense, Sonchus arvensis and Elymus repens was studied for plants collected from Denmark, Finland, Norway and Sweden. At 2-week intervals from July to October, 5-cm fragments of roots or rhizomes were cut from plants grown in buckets and planted into soil in pots, half of which were placed immediately into growth chambers at 18 degrees C for 4 weeks. The other half of the pots were initially placed in a dark room at 2 degrees C for 4 weeks before being transferred to the same growth chamber, also for 4 weeks. During the growth chamber period, the numbers of emerged shoots in each pot were counted weekly. The sprouting activity of C. arvense and E. repens was relatively uniform during this period and bud dormancy was not apparent. In all ecotypes of S. arvensis, innate bud dormancy developed during the latter part of the growing season. For all three species, differences in sprouting readiness were found among ecotypes. The results imply that C. arvense and E. repens are more likely to be controlled by mechanical measures in autumn than S. arvensis.
P>Autumn growth of weeds (i) provides an opportunity for mechanical and chemical control in autumn and (ii) can be important for weed survival and infestation in the following spring. Growth characteristics of Elytrigia repens, Cirsium arvense and Sonchus arvensis in autumn were studied in 2004 and 2005, on plants of different origins and developmental stages (planted at various times from May to August). The plants were grown outdoors in large pots and were assessed during September and October each year. The study showed that (i) all species grew in autumn, but growth ceased and the species withered at different times; S. arvensis first, followed by C. arvense and then E. repens and (ii) less developed (i.e. younger) plants grew later in the autumn. This was demonstrated by leaf area development and biomass distribution during autumn. Older plants had a greater total biomass with relatively more rhizomes or creeping roots than younger plants. In young plants of C. arvense and S. arvensis, the biomass of creeping roots increased during autumn. The total biomass, however, changed little during autumn. These growth patterns indicate that E. repens will be the easiest, S. arvensis the most difficult and C. arvense in between, regarding control of these species in autumn.
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The relative effects of using light (2-3 Mg) versus heavier (5-7 Mg) tractors, shallow (15 cm) versus deeper (25 cm) ploughing and on-land versus in-furrow wheel placement during ploughing were investigated from 2003 to 2006 in organic rotations (wheat or barley, green manure, oats with peas) and conventionally fertilized barley. Trials were located on loam soil in south-eastern Norway and silty clay loam in central Norway. Ploughing was performed in spring, when the topsoil moisture content was at or below field capacity, using single furrow ploughs that allowed alternative wheel placement and resulted in complete coverage of the surface by wheels each year (ca. 3 times the normal coverage during ploughing). Low tyre inflation pressures (:<= 80 kPa) were used throughout. The use of a heavy tractor increased topsoil bulk density slightly in the loam soil, and, in combination with in-furrow wheeling, it reduced air-filled pore space and air permeability at 18-22 cm. On the silty clay loam, the use of a heavy tractor did not increase bulk density, but it reduced air-filled pore space throughout the topsoil. In-furrow wheeling reduced air-filled pore space in this soil also, compared to on-land wheeling. Penetration resistance was in this soil always greater at 15-25 cm depth after shallow than after deep ploughing, especially with in-furrow rather than on-land wheeling. Shallow ploughing led on both soils to marked increases in perennial weed biomass compared to deep ploughing. Earthworms were hardly affected by the treatments, but in the loam in 2006 a higher number of individuals were found where the light rather than the heavy tractor had been used. Few significant treatment effects were found on grain yield and quality. Deep ploughing with a light tractor gave the highest wheat yield and protein content in 2 years on the loam soil, and on the silty clay loam the yield of conventionally fertilized barley was higher after deep than after shallow ploughing. In summary, limited evidence was found to support the use of on-land rather than in-furrow wheeling when ploughing is performed at favourable soil moisture and with tractor weights < 5 Mg. There is, however, reason to be wary of using heavy tractors (> 5 Mg), even under such conditions. With regard to ploughing depth in organic rotations dominated by cereals, the need to combat perennial weeds by deep ploughing weighs probably more heavily than any possible beneficial effect of shallow ploughing on stimulating nutrient turnover. (C) 2008 Elsevier B.V. All rights reserved.
Vips-Ugras er en samling av verktøy for å finne fram til optimaliserte blandinger og doser av ugrasmiddel til å bekjempe en gitt flora i vår og høstkorn. Det er nå også tatt høyde for at anbefalingene skal bidra til å forebygge og redusere resistens mot sulfonylurea-herbicid. Et nytt verktøy for sprøyteteknikk er under utvikling.
Vips-Ugras er en samling av verktøy for å finne fram til optimaliserte blandinger og doser av ugrasmiddel til å bekjempe en gitt flora i vår og høstkorn. Det er nå også tatt høyde for at anbefalingene skal bidra til å forebygge og redusere resistens mot sulfonylurea-herbicid. Et nytt verktøy for sprøyteteknikk er under utvikling.
Det er mange plantevernmidler som er godkjent mot ugras, men bare noen av dem er tillatt brukt i grøntanlegg. Endringer kan skje fra år til år. Plantevernmidler blir som regel godkjent for en 5 års-peride, før de revurderes av Mattilsynet. Oversikt over hvilke plantevernmidler som er tillatt brukt i norske grøntanlegg finnes på Plantevernguiden.no. I denne artikkelen gis en oversikt over ugrasmidler som er godkjente for bruk i 2008
Rynkerose (Rosa rugosa) er en av de fremmede plantene som i dag er i sterk ekspansjon på sandstrender, sanddyner og tangvoller, og som bidrar til å utkonkurrere hjemlige arter. Også mange verneområder har stor invasjon av rynkerose. I arbeidet med Norsk svarteliste 2007 (Gederaas m fl 2007) var rynkerose en av de 25 planteartene som risikovurdert og arten ble vurdert til å utgjøre høy risiko for stedegent biologisk mangfold.
CABI gjennomfører i 2008 en web-basert spørreundersøkelse om invaderende fremmede plantearter
Åkerstemorsblom tilhører den biologiske gruppen sommerettårige ugras, men kan i milde vintre også opptre som vinterettårig. Den voksne planten er 10-30 cm høy med tynn pålerot. Stengelen er mer eller mindre liggende, sjelden opprett, oftest noe greinet, kantet, glatt eller svakt håret. Bladene er bredt eggeformete med små innskjæringer i bladranden. Blomstene er små og lyse, med gule, ofte nesten hvite kronblad, de to øvre av og til fiolette. Formeringen og spredningen skjer utelukkende med frø. Blomstring fra mai til september. Forekommer i åker, veikanter og på avfallsplasser. Vokser på de fleste jordtyper, unntatt vassjuk jord. Opptrer som ugras i hager, parker og alle typer åkerkulturer, særlig i åpne radkulturer. Forebyggende tiltak og mekaniske tiltak som for andre sommerettårige ugras, for eksempel meldestokk. Motstandsdyktig (resistent) mot mange kjemiske ugrasmidler, særlig sulfonylureapreparater.
Lyssiv hører til den biologiske ugrasgruppen flerårige, vandrende på "andre måter", med korte, lubne jordstengler (som knappsiv). Den voksne planten er 30-70 cm høy. Stengelen er opprett, bladløs, stripete, glinsende og friskt grønn. Bladene er basale, slireliknende og mørkebrune. Støttebladet til blomsterstanden går rett opp, som om det skulle være toppen av strået. Planten har de bleikt brune blomstene på siden av stengelen i løs, åpen kvast. Formeringen og spredningen skjer hovedsakelig med frø, men i en viss utstrekning også ved hjelp av den langsomt krypende jordstengelen. Danner derved tette tuer. Forekommer i grasmark, på myr, langs elver og bekker. Opptrer som ugras i eng, beite og åpne grøfter, særlig i Sør-Norge. Bekjempelse: Grøfting av våt jord, pussing av beite, sprøyting med MCPA.
Landøyda tilhører den biologiske gruppen flerårige, stedbundne med rotstokk. Stengelen er opprett og sterkt greinet ovenfor midten, grov, stiv og furete med brun-rød fargetone. Bladene ved basis er stilkete og finnet med fjærdelte småblad som er utvidet mot spissen. De øvre bladene er sittende, finnet med taggete småblad. Planten har smørgule blomsterkorger i flate halvskjermer. Forekommer i natureng, beitemark og tørrbakke, langs skogkanter, veier og grøfter. Liker best sur, lettere sand-, grus- og moldjord. Opptrer som ugras i eng og beite. Vanlig i kyst- og fjordstrøk til Sogn og Fjordane. Planten er giftig for storfe og hest, men vrakes vanligvis av husdyrene. Bekjempelse: Bør hogges av før frøsetting. Kan også bekjempes ved å grave opp rotstokken. Glyfosat (Roundup) og fenoksysyrer er effektive.
Knappsiv hører til den biologiske ugrasgruppen flerårige, vandrende på "andre måter", med korte, lubne jordstengler (som lyssiv). Den voksne planten er 30-70 cm høy. Stengelen er opprett, bladløs, fint stripete, litt ru, og grågrønn. Bladene er basale, slireliknende og lysebrune. Støttebladet til blomsterstanden går rett opp, som om det skulle være toppen av strået. Planten har de gulbrune, eller rødbrune blomstene på siden av stengelen, vanligvis samlet i et tett, rundt hode. Formeringen og spredningen skjer hovedsakelig med frø, men i en viss utstrekning også ved hjelp av den langsomt krypende jordstengelen. Danner derved tette tuer. Forekommer i grasmark, på myr, langs elver og bekker. Opptrer som ugras i eng, beite og åpne grøfter, særlig i Sør-Norge. Bekjempelse: Grøfting av våt jord, pussing av beite, sprøyting med MCPA.
Klistersvineblom tilhører den biologiske gruppen sommerettårige ugras. Den voksne planten er 25-50 cm høy, med uregelmessig fingreinet pålerot. Stengelen er opprett med mange utsperrete greiner. Bladene er omvendt eggformet, finnet med grovtaggete finner, nederst kortstilkete, øverst sittende. Den overjordiske delen av planten er tett besatt med klebrige kjertelhår. Planten har sterk og ubehagelig lukt. Planten har gule blomster med korte, tungeformete kantkroner, ofte nedrullet. Frøet har fnokk. Formeringen og spredningen skjer utelukkende med frø. Forekommer på avfallsplasser, industritomter, langs veikanter, jernbaneskråninger, i berg, ur, tangvoller og på grus- og sandstrand, til dels også i åpen åker. Kan lokalt opptre som ugras på disse vokseplassene. Mottiltak: Hindring av frøspredning ved tidlig slått eller avkutting. Klistersvineblom synes å være mer motstandsdyktig mot kjemiske midler enn åkersvineblom, men ellers anbefales de samme midlene.
Burot tilhører den biologiske gruppen flerårig stedbundne ugras med rotstokk.Den voksne planten er 0,5 " 2,0 m høy, med tykk, treaktig rotstokk. Stengelen er opprett, grov, ofte rødbrun. Bladene er finnete med spisse småblad. Basale blad er kortstilkete, stengelblad sittende og stengelomfattende. Oversiden er mørkegrønn, undersiden kvitfiltrert. Blomsterkorgene sitter i mange aksliknende klaser fra bladhjørnene. Formeringen og spredningen skjer mest ved frø (opptil 700 000 pr. plante), men også ved at nedre del av stenglene slår røtter, og ved mekanisk oppdeling av rotsystemet. Forekommer på dyrket og udyrket mark, på veikanter, langs gjerder og hekker, på tomtearealer og avfallsplasser. Liker varm jord, rik på kalk og næring. Opptrer som ugras i åker, eng og beiter. Pollenet er sterkt allergifremkallende. Burot kan motarbeides ved avhogging før blomstring, og oppstikking av rotstokken. Fenoksypropionsyrer har bra virkning, mens MCPA og sulfonylureapreparater er svake.
Arter innenfor bjørnekjeksslekta hører med blant de fremmede artene som i dag er i sterk spredning i kulturlandskapet. Fremmede arter utgjør en trussel mot det biologiske mangfoldet, fordi de fortrenger stedegne arter og forstyrrer lokale økosytemer. I denne fagartikkelen sammenstilles eksisterende kunnskap om bjørnekjeksslekta og de erfaringene man har med ulike tiltak for å bekjempe dem. I områder hvor bjørnekjeks skal bekjempes og der man samtidig ønsker å ivareta biologisk mangfold må spesielle hensyn tas.
Powerpoint-presentasjon: Rapport: "Erfaringer med bekjempelse av fremmede planter i Oslo 2007", tiltak v/ Friluftsetaten. Bioforsk Plantehelse: Forslag til justeringer. Kjempebjørnekjeks: Forsøk ved Bioforsk Plantehelse , kort om biologi, kort om forsøksresultater, tiltak v/ Friluftsetaten og forslag til justeringer.
Forsøksresultater fra middelprøving 2008 - luket rapport
In stockless organic cereal systems undersowing a legume shortly after sowing of cereals is a commonly used practice. Nitrogen supply as well as retarded growth of annual weeds is mentioned as benefits of such use of legumes in cropping systems. There is, however, limited knowledge on the influence of undersown cover crops on the growth of perennial weeds. This issue was addressed in a field experiment (#1) at Ås in South-eastern Norway. Furthermore, a second series of field experiments (#2) aimed at investigating the influence of (i) time of ploughing and (ii) that of black fallow. To obtain a field (#1) with uniform distribution of the perennial weed species, root fragments of Cirsium arvense (L.) Scop. and Sonchus arvensis L. and rhizomes of Elymus repens (L.) Mould., were transplanted by hand in the spring of 2002. The experiment, designed as a split-plot with 3 replicates, was initiated in 2003 and continued until the autumn of 2006. Oat undersown with red clover versus oat alone composed each year the two main plot treatments, except in 2006, in which the whole field was seeded to oat without red clover. Each mean plot was divided into four sub-plots with mechanical treatments in autumn: 1) untreated control; 2) mowing; 3) rotary tilling and 4) shallow ploughing plus harrowing. The autumn treatments were only carried out in 2004 and 2005. The number of weeds was counted at different dates throughout the growing season, and the weed biomass was assessed just before harvest. Preliminary results showed that red clover undersown in oat, compared to oat alone, had limited and in most cases insignificant effects on biomass and number of shoots of all investigated species. No significant interaction between red clover and mechanical treatments in autumn was found. Shallow ploughing suppressed E. repens most, followed by rotary tilling, mowing and untreated, in that order. On S. arvensis, mowing showed the best control, and rotary tilling the poorest. On C. arvense, significant differences between treatments were detected only in 2005, when rotary tilling and shallow ploughing reduced the weed biomass significantly compared to the untreated control.In the second experiment series (#2) C. arvense, S. arvensis and E. repens are subjected to the following treatments: 1) black fallow (soil cultivation) + ploughing in autumn 2) ploughing in autumn 3) spring ploughing, and 4) black fallow + ploughing in spring. Preliminary results from the first experimental year have shown very clear interactions between treatment and weed species: Time of ploughing did not influence the growth of E. repens significantly. On the other hand fallow in autumn suppressed this species more efficiently than fallow in spring. In general, C. arvense and S. arvensis showed the opposite behaviour regarding both time of ploughing and effect of fallow. Spring ploughing, as well as spring fallow, suppressed these species more than treatments in autumn. However, not all comparisons were significantly different. Although the results need more attention as well as new experiments before detailed recommendations can be given, the studies indicate clearly that the effect of different treatments including time of ploughing and soil cultivation periods depends on weed species.
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De viktigste ugrasartene ved frødyrking er balderbrå, markrapp, kveke, tunrapp og knereverumpe.
Frøugrasfrøbanken: * "Forteller" noe om driften. * Forhindre frøsetting mest mulig, både i selve grønnsakkulturen og i "saneringskulturen" * Alltid en balansegang mellom ugrasutviklingen og kostnadene ved ugraskontrollen Rotugras: * Rotugrasfrøbank utgjør bare 2-3% av total frøbank * Rotugraset bør bekjempes mest mulig i "saneringskulturen
De viktigste biologiske gruppene er: Sommerettårige, vinterettårige, toårige, flerårig og stedbundne ,og flerårig og vandrende arter.
Generelt kan en si at frøbank er summen av levedyktige frø nedi jorda, både de som er mer eller mindre i hvile (dormante) og de som er spiredyktige umiddelbart. Frø på jordoverflata regnes ofte også som en del av frøbanken.
Grønngjødslingseffekten, spesielt N-tilførselen, er hovedgrunnen til undersådd kløver i økologisk kornproduksjon. Effekten på ettårig ugras var ett av hovedspørsmålene i prosjektet.
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Bruk av anbefalingene fra beslutningsstøttesystemet VIPS-Ugras har et stort potensial for reduksjon i bruken av ugrasmiddel i korn. VIPS-Ugras er også et verktøy som bør utnyttes i arbeidet med å hindre resistensutvikling. Brukervennligheten i forhold til omfang av registreringsarbeidet må økes.
ugras i skogplanteskoler
I årene 1934-38 ble det laget 90 plansjer etter professor Emil Korsmos anvisninger. Etter mye dataarbeid, kan vi nå glede leserne med at de fleste ugrasplansjene etter Korsmo (1863-1953) nå blir tilgjengelig på digital form.
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I 2005 blei det utført forsøk for å evaluere utgåva av VIPS-Ugras som vi har utarbeidd for vårsprøyting mot ugras i haustkorn. Tre norske prototypar av det danske systemet Plantevern Online (Rydahl 2003) blei testa i til saman 9 feltforsøk. I dei tre prototypane blei høgt, medium og lågt effektkrav lagt til grunn
Resultater fra en spørreundersøkelse om erfaringer med bruk av Hussar i timoteifrøeng i Vestfold, viser at Grindstad kan være en sterkere sort enn Vega og Noreng. Det er mulig det blir mer skade av Hussar ved tidlig sprøyting i timotei. Det var effekt av dose på graden av skade. Resultatene bekrefter av Hussar er effektiv mot markrapp og knerevrumpe, men variabel mot tunrapp.
Kjempebjørnekjeks er en 2-4 m høy skjermplante, innført til Norge som prydplante på 1800-tallet. Planten er vanligvis toårig. Den kan være plagsom i kulturlandskap, hager og parker. Plantesaften kan på bar hud, i kombinasjon med sollys, gi stygge brannskader. Derfor bør planten bekjempes - og på riktig m åte.
Effekt av ulike typer jordarbeiding på populasjonsdynamikk til meldestokk, kvassdå, balderbrå og stivdylle ble presentert. Antall planter, frøproduksjon og frøbanken i jorda ble registrert og brukt til utvikling av populasjonsdynamiske modeller for enkeltartene.
I fire feltforsøk i vårkorn som varte fra 1993 til 2000, ble oppspirte ugras på forsommeren relatert til frøbanken om høsten 1993, 1996 og 1999. Prosent oppspirte ugras fra frøbanken varierte avhengig av ugrasart, jordarbeiding og ugrassprøyting. Variasjon i været på ulike steder og år påvirket oppspiringa. Temperatur før såing og nedbør etter såing var viktig for oppspiring av mange arter. For totalt antall ugras påvirket vintertemperaturen oppspiringa.
Avløpsvann, slam og kompost er potensielle smittekilder av planteskadegjørere for ulike planteskadegjørere. Gjennom kontrollert behandling elimineres smittefaren på en effektiv måte.
Håndtering av ugress og andre plantevernutfordringer er viktig for å unngå avlingstap i landbruket. Tilbudet av norske rå-, mat- og fôrvarer påvirkes av at bonden lykkes med sin innsats i åker og frukthager. Et nylig forbud mot plantevernmiddelet dikvat og den usikre framtida til glyfosat – begge viktige innsatsfaktorer i norsk jord- og hagebruk – fordrer nye løsninger. Gode alternativ til ordinære plantevernmidler er dessuten velkomne som verktøy i integrert plantevern (IPV). Norske dyrkere er siden 2015 pålagt å følge IPV. Hensikten med IPV er blant annet redusert risiko ved bruk av plantevernmidler på helse og miljø.
Målsetningen med prosjektet AC/DC-weeds er å utvikle metoder for bærekraftig kontroll av flerårig vandrende ugras (rotugras) som kveke, åkerdylle og åkertistel i landbruket. Målet er å redusere behovet for intensiv jordarbeiding som pløying og å finne alternativer til bruk av ugrasmiddelet glyfosat. Nye metoder for bærekraftig kontroll av rotugras krever at en kombinerer flere typer av både forebyggende og direkte bekjempingstiltak. Kunnskap fra prosjektet vil formidles til viktige målgrupper som rådgivere, bønder og andre relevante mottakere. Rostock Universitet (Tyskland) ved Prof. Dr. Bärbel Gerowitt er prosjektkoordinator. NMBU ved Prof. Dr. Lars Olav Brandsæter administrerer aktiviteten i Norge.
Hønsehirse (Echinochloa crus-galli) er en ugrasart som er et økende problem i Norge. Ugresset har spredd seg de seinere årene fra områder nær Oslofjorden og har etablert fra Aust-Agder i sør til Hedmark i nord. Godt tilpassa biotyper i Østfold og Vestfold konkurrerer i dag godt i vårkorn og kan gi store avlingstap. Avlingstapet i mindre konkurransedyktige kulturer som grønnsaker vil være mye høyere enn i korn. Rådgivere og bønder hevder at de har problemer med å kontrollere hønsehirse selv med effektive plantevernmidler tilgjengelige. I motsetning til Norge, er hønsehirse ikke ansett som et stort problem i vårkorn i andre nordiske land.
Det er et mål i Norge å øke grovfôrproduksjon. Ugras i grasmark kan avhengig av mengde og hvilke arter som dominerer, redusere grovfôravlingen og redusere eller øke kvaliteten på fôret. Hovedmålet i dette prosjektet er å utvikle integrerte ugrastiltak som opprettholder høye grovfôravlinger med minst mulig bruk av plantevernmidler. Hovedhypotesen er at ugrasbekjempelse i fornyingsfasen reduserer på behovet for plantevernmidler i de påfølgende engårene og vil føre til økt avling og bedre lønnsomhet.
Det er en sterk økning i introduksjon og etablering av nye planteskadegjørere og andre invaderende fremmede arter til nye land og regioner. Dette ser primært ut til å være forårsaket av økt internasjonal handel og import av planter, planteprodukter og jord. Klimaforandringene er med på å tilrettelegge for at de introduserte artene kan etablere seg i nye klimatiske områder.
