Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2008
Sammendrag
Most fungicide applications targeting apple scab aim to control primary infections caused by ascospores and spraying is thereby linked to ascospore availability. We investigated the effect of pre bud break climatic conditions on seasonal patterns of ascospore release. Apple leaves bearing pseudothecia of Venturia inaequalis were overwintered at orchard sites in 8 countries for up to 3 years. Leaf samples were collected 2 to 5 weeks before bud break and again at bud break, air dried, and sent via airmail to Norway. The samples were stored at -18 ºC upon arrival until tested. Disks cut from each replicate leaf sample were incubated moist at 20 ºC to allow ascospore maturation but prevent discharge. Matured ascospores were induced to discharge twice a week and enumerated until the supply was exhausted. The proportion of ascospores ejected was fitted against degree day accumulation using logistic regression. The regression intercept (onset maturation), slope (maturation rate), as well as the absolute number of spores counted differed significantly (P < 0.001, P = 0.05, P < 0.001 respectively) among sites and sampling dates. There was a significant interaction between site and sampling date, indicating that climatic conditions prior to bud break differentially impacted the subsequent ascospore availability. Observed differences could perhaps be used to further refine previously described models of ascospore maturity.
Forfattere
Arne StensvandSammendrag
Black spot caused by Colletotrichum acutatum is occasionally found in strawberry fields in Norway. It was detected for the first time in 1999 and found in certified production in 2002. More than half of the certified nurseries, including the elite plant station, had symptomless infections of C. acutatum in strawberry planting material the following two years. A renovation programme was carried out, and in 2005 and 2006 C. acutatum was found in only one certified nursery. However, in 2007 latent infections of C. acutatum was detected in four certified strawberry plant nurseries. As been reported before from Norway, C. acutatum is present in almost all fruit and berry species grown in the country and has also been found on many ornamentals and in weeds, but it is a quarantine organism only in strawberry. It is particularly severe in cherry and apple. We have detected the perfect stage of the fungus in highbush blueberry, and when isolating the fungus we find a high frequency of isolates forming the perfect stage in culture. When doing genetic analysis (AFLP), the Norwegian isolates from strawberry separated in two groups. One set of isolates grouped together with strawberry isolates of C. acutatum from other countries, and the other set grouped with Norwegian isolates from several hosts, with a majority of isolates from sweet- and sour cherry. The latter group had more than 90% similarity between the polymorphic bands. There was also a third, very genetically diverse group of isolates that included most of the perithecia forming isolates. Further research will reveal if isolates from the different groups may vary in their aggressiveness to strawberry and if it will be possible to distinguish between them in simple molecular tests.
Forfattere
Arne Stensvand Maria Herrero Håvard Eikemo Andrew Dobson Belachew Asalf David M. Gadoury Robert C. Seem Catherine Heidenreich Mary Jean WelserSammendrag
Artikkelen omtalar resultat frå eit 4-årig prosjekt om mjøldogg i jordbær.
Sammendrag
Artikkelen omhandlar rotstokkrote og lerrote i jordbær som begge er årsaka av Phytophthora cactorum.
Forfattere
Arne Stensvand Maria Herrero Håvard Eikemo Andrew Dobson David M. Gadoury Robert C. Seem Catherine Heidenreich Mary Jean WelserSammendrag
Artikkelen gir ein kort omtale av resultat frå eit forskingsprosjekt om mjøldogg i jordbær.
Forfattere
Arne StensvandSammendrag
Artikkelen er ein omtale av Signum (aktive stoff: pyraklostrobin og boskalid) og inkluderer resultat frå utprøvingar av preparatet i Noreg.
Forfattere
Ricardo HolgadoSammendrag
I verdensmålestokk er potetcystenematoder (PCN) (Globodera spp.) Kjent som alvorlige skadegjørere på potet. Nematodenes sterke spesialisering til potet som vertsplante har ført til en overlevelsesevne i jord som er stor utfordring for potetdyrkingen. Virulente populasjoner som kan oppformeres på resistent potet er en annen grunn for bekymring. Både den gule arten (yPCN) G. rostochiensis og den hvite arten (wPCN) G.pallida er klassifisert som karanteneskadegjørere og er regulert i Matloven. Bekjempelse av ikke virulent (yPCN) bygger på vekstskifte med resistent potet, ikke-vertsplanter og mottakelig potet. Bekjempelse av wPCN gjøres i dag ved at infiserte bruksenheter legges i karantene i 40 år med dyrkingsforbud for vertsplanter og annen aktivitet som risikere å sprede nematoden.
Forfattere
Ricardo Holgado Anette Stryken Christer Magnusson Irene Rasmussen Kari-Ann Strandenæs Bonsak HammeraasSammendrag
A survey was undertaken to investigate the occurrence of plant parasitic nematodes in the municipality of Lier located in southern Norway. A wide variety of vegetables crops are grown in this area. Soils in Lier are mostly sandy loam, and irrigation is practiced when necessary during the growing season. There is little information on the occurrence on plant parasitic nematodes in vegetables; particularly in areas where farmers have specialized in intensive production, and often grow two to three cultures of vegetables during the growing season. In the year prior to this investigation several crops had been observed with symptoms of attack by plant parasitic nematodes. The aim of this survey was to identify the species responsible for the damage. The emphasis was placed on genera of known economic importance. During the end of the growing season plants showing poor growth or symptoms of nematode damage and plants with healthy appearance were sampled. A total of 74 root samples were collected and assessed for galls and 37 soil samples were collected from the rhizospheres. In the study samples were collected from 7 producers. Five samples were taken from cauliflower (Brassica oleraceae var. botrytis), 4 from broccoli (Brassica oleraceae var. italica), 8 from pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis), 8 from lettuce (Lactuca sativa) and 1 from celery (Apium graveolens). Soil sampling included 11 samples from areas with fallow, ploughed and rotocultivated land. Root knot nematodes were not recorded in the root samples. In soil samples economically important nematode genera were recorded. Tylenchorhynchus sp. (72.9 % of samples), was the most frequently encountered genus, followed by the species Heterodera cruciferae and other Heterodera spp. (67.5 %), Pratylenchus spp. (54 %), Paratylenchus spp. (29,7 %), and Helicotylenchus spp. (8.1 %). In addition to cyst detections Heterodera juveniles were found in 32.4 % of samples. In all the samples from Pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis) Heterodera cruciferae was recorded, symptoms of nematode damage was also observed in the field. The results of the survey will help in planning future research as well as in developing effective nematode management strategies suitable for vegetable producer particularly in this area. The authors are thankful to the FMLA in Buskerud County for economical support.
Forfattere
Ricardo Holgado Anette Stryken Christer Magnusson Irene Rasmussen Kari-Ann Strandenæs Bonsak HammeraasSammendrag
A survey was undertaken to investigate the occurrence of plant parasitic nematodes in the municipality of Lier located in southern Norway. A wide variety of vegetables crops are grown in this area. Soils in Lier are mostly sandy loam, and irrigation is practiced when necessary during the growing season. There is little information on the occurrence on plant parasitic nematodes in vegetables; particularly in areas where farmers have specialized in intensive production, and often grow two to three cultures of vegetables during the growing season. In the year prior to this investigation several crops had been observed with symptoms of attack by plant parasitic nematodes. The aim of this survey was to identify the species responsible for the damage. The emphasis was placed on genera of known economic importance. During the end of the growing season plants showing poor growth or symptoms of nematode damage and plants with healthy appearance were sampled. A total of 74 root samples were collected and assessed for galls and 37 soil samples were collected from the rhizospheres. In the study samples were collected from 7 producers. Five samples were taken from cauliflower (Brassica oleraceae var. botrytis), 4 from broccoli (Brassica oleraceae var. italica), 8 from pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis), 8 from lettuce (Lactuca sativa) and 1 from celery (Apium graveolens). Soil sampling included 11 samples from areas with fallow, ploughed and rotocultivated land. Root knot nematodes were not recorded in the root samples. In soil samples economically important nematode genera were recorded. Tylenchorhynchus sp. (72.9 % of samples), was the most frequently encountered genus, followed by the species Heterodera cruciferae and other Heterodera spp. (67.5 %), Pratylenchus spp. (54 %), Paratylenchus spp. (29,7 %), and Helicotylenchus spp. (8.1 %). In addition to cyst detections Heterodera juveniles were found in 32.4 % of samples. In all the samples from Pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis) Heterodera cruciferae was recorded, symptoms of nematode damage was also observed in the field. The results of the survey will help in planning future research as well as in developing effective nematode management strategies suitable for vegetable producer particularly in this area. The authors are thankful to the FMLA in Buskerud County for economical support.
Sammendrag
Nokre planter er det rett og slett forbod mot å planta, så som pile- og bulkemispel, på grunn av pærebrann. Eit anna døme er ask, der det no er restriksjonar på flytting av planter til smittefrie sonar på grunn av askeskotsjuke. Dessutan er det mange planter som er så utsette for sjukdom at ein bør unngå dei på grunn av redusert prydverdi.