Biografi

Jeg jobber med biologi og bekjempelse av ugras knyttet til:

  • grasmark
  • fôrvekster
  • plenarealer relatert til grøntanlegg (inkludert golf)
  • frukt og bær

I tillegg jobber jeg med fremmede invaderende plantearter og herbicidresistens hos ugras.

Les mer

Sammendrag

Weed-free zone underneath apple trees is important to maximize vegetative growth, fruit yield- and quality. Glyphosate applied twice is the usual strategy in apple orchards in Norway. Due to uncertain future of glyphosate there is a need for alternative strategies. A field trial was conducted during 2021 in an orchard (three-year-old trees). Five alternative strategies were tested: 1) Hot water at 3 L m-2 x 3 (spring, early summer, summer), 2) Hot water at 6 L m-2 x 3 (times as previous), 3) Pelargonic acid at full dose (10.9 kg a.s. ha-1) x 1 (early summer), 4) Pelargonic acid at half dose (5.44 kg a.s. ha-1) x 2 (spring, early summer), and 5) Rotary hoe x 3 (early spring, early summer, summer). Glyphosate at 1.08 kg a.s. ha-1 x 2 (early summer, summer) was included as reference strategy. Hot water (about 80 C, 0.1 bar) was applied with a commercial machine (Heatweed Technologies, Norway). Visual assessments of percentage of ground covered by living vegetation were used to estimate weed control efficacy. Dominating species were Taraxacum officinale, Tripleurospermum inodorum, Poa annua, Polygonum aviculare, Galium aparine, Viola arvensis and Senecio vulgaris. Assessed mid-summer (June 24), hot water applied twice (both 3 L m-2 and 6 L m-2) showed very high efficacies, both about 90%. Pelargonic acid showed rather low efficacies, about 15% (10.9 kg a.s. ha-1 x 1) and 45% (5.44 kg a.s. ha-1 x 2). Rotary hoe twice had almost 60%. Efficacy of glyphosate once was 75%. The last assessment was conducted in mid-July, i.e. about 1-2 weeks after the last application of hot water, rotary hoe and glyphosate. The two hot water strategies resulted in very good weed control, i.e. < 1% total weed cover. This was in same order as the glyphosate strategy (about 4% total weed cover), but better than the rotary hoe strategy (9% total weed cover). The results of the first trial in study showed very good efficacy of hot water, especially against annual weeds. There seemed to be no benefit of doubling hot water from 3 to 6 L ha L ha-1. Repetition is needed to confirm this. Acknowledgement: This work was part of project SOLUTIONS financed by FFL-JA (RCN, grant No. 319588.), Grofondet (grant No. 190029), A-K maskiner, Heatweed Technologies, Kilter, Norwegian Agricultural Extension Service and producers. M. Meland (NIBIO), E. Bjotveit, G. Myren, K. Rofstad (all Norwegian Agricultural Extension Service) and A. Freberg are acknowledged for their inputs and field work. Keywords: Non-chemical weed control, thermal weed control, alternatives to glyphosate, Integrated Weed Management.

Sammendrag

Reusing soil can reduce environmental impacts associated with obtaining natural fresh soil during road construction and analogous activities. However, the movement and reuse of soils can spread numerous plant diseases and pests, including propagules of weeds and invasive alien plant species. To avoid the spread of barnyardgrass in reused soil, its seeds must be killed before that soil is spread to new areas. We investigated the possibility of thermal control of barnyardgrass seeds using a prototype of a stationary soil steaming device. One Polish and four Norwegian seed populations were examined for thermal sensitivity. To mimic a natural range in seed moisture content, dried seeds were moistened for 0, 12, 24, or 48 h before steaming. To find effective soil temperatures and whether exposure duration is important, we tested target soil temperatures in the range 60 to 99 C at an exposure duration of 90 s (Experiment 1) and exposure durations of 30, 90, or 180 s with a target temperature of 99 C (Experiment 2). In a third experiment, we tested exposure durations of 90, 180, and 540 s at 99 C (Experiment 3). Obtaining target temperatures was challenging. For target temperatures of 60, 70, 80, and 99 C, the actual temperatures obtained were 59 to 69, 74 to 76, 77 to 83, and 94 to 99 C, respectively. After steaming treatments, seed germination was followed for 28 d in a greenhouse. Maximum soil temperature affected seed germination, but exposure duration did not. Seed premoistening was of influence but varied among temperatures and populations. The relationships between maximum soil temperature and seed germination were described by a common dose–response function. Seed germination was reduced by 50% when the maximum soil temperature reached 62 to 68 C and 90% at 76 to 86 C. For total weed control, 94 C was required in four populations, whereas 79 C was sufficient in one Norwegian population.

Sammendrag

Established invasive alien plant species make it difficult and costly to move and make use of infested soil in public and private construction work. Stationary soil steaming as a non-chemical control method has the potential to disinfect soil masses contaminated with seeds and other propagative plant materials. The outcome can vary depending on steaming temperature and duration. Higher temperatures and longer durations are relatively more efficient but may also have side-effects including change in soil physical and chemical characteristics. Barnyard grass (Echinochloa crus-galli) is among troublesome invasive species in Norway. We have tested different steam duration at 99°C to find the possible lowest effective exposure duration for killing seeds of this annual grass species. Four replications of 40 barnyard grass dry seeds of one population were placed in polypropylene-fleece bags (9*7 cm), moistened for 12 hours, and covered by the soil at a depth of 7 cm in 60*40*20 cm boxes. The boxes with soil and bags were steamed at 99°C for 1.5, 3 and 9 min. The bags including steamed seeds were taken out, opened, placed on soil surface in pots and covered by a thin layer of soil. The pots were placed in greenhouse and watered from below and seed germination was followed for a month. Moistened non-steamed seeds were used as control. It was shown that steaming at 99°C gave 0% germination indicating that 100% of the seeds were killed regardless of exposure duration while in the control seed germination was 100%. Consequently, to achieve an efficacy of 100%, exposure duration of 1.5 min would be enough. Finding the lowest possible steam temperature and exposure duration to get the highest possible seed killing in a seed mixture of different plant species as well as other factors to increase the heat transferability are under investigation. Keywords: Echinochloa crus-galli; Resource recovery; Steaming temperature and duration; Thermal soil disinfection

Sammendrag

Soil disinfestation by steaming is being reconsidered for its efficiency in controlling or even eradicating pathogens, nematodes and weed seeds, particularly to avoid excess use of pesticides. Most weeds within a field result from seeds in the soil seedbank and therefore management of weed seeds in the soil seedbank offers practical long-term management of weeds, especially those difficult to control. We investigated the possibility of thermal control of seeds of grass weeds Bromus sterilis (barren brome) and Echinochloa crus-galli (barnyardgrass) using a prototype of a soil steaming device. Five different soil temperatures of 60, 70, 80, 90 and 99°C with an exposure duration of 3 min were tested. Four replications of 50 seeds of each species were placed in polypropylene-fleece bags. Bags in the same replicate of each target temperature were placed at the bottom of one plastic perforated basket container and covered by a 7-cm soil layer. Each basket was placed in the steaming container and steam was released from the top and vacuumed from the bottom of the container. Soil temperature was monitored by 10 thermocouples and steaming was stopped when 5 of the thermocouples had reached the target temperature. The basket was then removed from the steaming container after 3 min exposure time. Bags were taken out, opened, placed on soil surface in pots and covered by a thin layer of soil. Seed germination was followed for 8 weeks in the greenhouse. Non-steamed seeds were used as controls. It was shown that soil temperatures of 60, 70, 80, 90 and 99°C lasting for 3 min reduced the seed germination of barren brome by 83, 100, 100, 95 and 100% and seed germination of barnyardgrass by 74, 69, 83, 89 and 100% respectively, compared to the controls. Germination rate of control seeds were 94 and 71% for barren brome and barnyardgrass, respectively. These results show a promising seed mortality level of these two weed species by steaming and that steam is a potential method to control weed seeds, however further studies are needed to investigate the effect of other factors such as soil type and moisture content. Keywords: Non-chemical weed control, thermal soil disinfection, weed seedbank

Sammendrag

Invasive plant propagative material can be introduced to new regions as contaminants in soil. Therefore, moving soil should be done only when the soil has been verified to be free of invasive species. Stationary soil steaming as a non-chemical control method has the potential to disinfect soil masses contaminated with invasive species. We investigated the possibility of thermal control of propagative material of Bohemian knotweed (Reynoutria × bohemica) in two experiments using a prototype of a soil steaming device. Five soil temperatures of 60, 70, 80, 90 and 99 °C with an exposure duration of 3 min were tested. In each replicate and target temperature, rhizome cuttings containing at least two buds and shoot clumps were placed at the bottom of a plastic perforated basket and covered by a 7-cm soil layer. Each basket was placed in the steaming container and steam was released from the top and vacuumed from the bottom. Soil temperature was monitored by 10 thermocouples and steaming was stopped when 5 of the thermocouples had reached the target temperature. The basket was then removed from the steaming container after 3 min. Plant materials were taken out and planted in pots. Buds sprouting was followed for 8 weeks. Non-steamed plant materials were used as controls. Results showed 100% rhizome death at soil temperatures of ≥70 and 99 °C in the first and second experiments, respectively. Shoot clumps death was obtained at ≥90 °C in both experiments. These results showed that steaming at 99 °C for 3 min can guarantee control of Bohemian knotweed in infested soils supporting the steam treatment as a potential method of disinfecting soil against invasive species. However, depending on the intended re-use of the soil, further studies are needed on the effect of potential negative impacts of high temperatures on the soil quality.

Sammendrag

Eradication of alien invasive species in the soil with steam as an alternative to chemical fumigation may allow contaminated soil to be reused. We have investigated steam disinfestation of soil to combat invasive plant species in three experiments including different temperatures and exposure durations using a prototype stationary soil-steaming device. The experiments included effects on seed germination of bigleaf lupine (Lupinus polyphyllus Lindl.), ornamental jewelweed (Impatiens glandulifera Royle), and wild oat (Avena fatua L.; one population from Poland and one from Norway), as well as effects on sprouting rhizome fragments of Canada goldenrod (Solidago canadensis L.) and Bohemian knotweed (Reynoutria x bohemica Chrtek & Chrtková). In Experiment 1, we tested four different soil temperatures of 64, 75, 79, and 98 C with an exposure duration of 90 s. In Experiments 2 and 3, we tested exposure durations of 30, 90, and 180 s and 90, 180, and 540 s, respectively, at 98 C. Seed pretreatment of 14 d cooling for L. polyphyllus and I. glandulifera, no seed pretreatment and 12-h moistening for A. fatua populations, and 5- and 10-cm cutting size for R. x bohemica were applied. Our results showed germination/sprouting was inhibited at 75 C for I. glandulifera (for 90 s) and 98 C for the other species; however, longer exposure duration was needed for L. polyphyllus. While 30 s at 98 C was enough to kill A. fatua seeds and S. canadensis and R. x bohemica rhizome fragments, 180-s exposure duration was needed to kill L. polyphyllus seeds. The results showed promising control levels of invasive plant propagules in contaminated soil by steaming, supporting the steam treatment method as a potential way of disinfecting soil to prevent dispersal of invasive species.

Sammendrag

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.

Sammendrag

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.

Sammendrag

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.

ef-20080906-121830

Divisjon for bioteknologi og plantehelse

SOLUTIONS: New solutions for potato canopy desiccation, control of weeds and runners in field strawberries & weed control in apple orchards


Efficient measures for weed control and similar challenges are vital to avoid crop loss in agriculture. National supply of food, feed and other agricultural products depends on each farmer’s success managing their fields and orchards. The recent loss of the herbicide diquat, and the potential ban on glyphosate, - both important tools for farmers -, raise a demand for new measures for vegetation control. Efficient alternatives to herbicides are also important tools in Integrated Pest Management (IPM). Norwegian growers need to document compliance to IPM since 2015 to ensure minimum hazards to health and environment from pesticide use.

Active Updated: 22.04.2022
End: des 2024
Start: jan 2021
ef-20080906-121830

Divisjon for bioteknologi og plantehelse

SOLUTIONS: Nye løsninger for nedvisning av potetris, bekjempelse av ugras og utløpere i jordbær og ugraskontroll i eplehager


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.

Active Updated: 24.05.2022
End: des 2024
Start: jan 2021
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Divisjon for bioteknologi og plantehelse

RessursRetur – Ny vanndampteknologi omdanner biologisk forurensede jordmasser og planteavfall til nye ressurser


Bærekraftig bruk og vern av naturressurser er et viktig prinsipp i den sirkulære bioøkonomien. Flytting av jord fra utbyggings- og samferdselsprosjekter til nye areal og utnyttelse av planteavfall til gjødsel eller jordforbedring kan bidra til at ressurser gjenbrukes godt. Ved utbygging av veier, jernbane og eiendom går i dag mye dyrkbar jord tapt fordi jorda ofte inneholder uønskede organismer som det er forbudt å spre. Eksempler på uønskede organismer eller "biologisk forurensing" er åkerugress slik som floghavre, fremmede plantearter som kjempespringfrø, sykdomsfremkallende sopp som løkhvitråte, og planteparasittære nematoder som potetcystenematode og rotgallnematode. Planteavfall fra produksjon og import av grønnsaker er også uutnyttede ressurser på grunn av risiko for innhold og spredning av farlige planteskadegjørere.

Active Updated: 15.12.2021
End: mars 2025
Start: apr 2021