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.
2007
Sammendrag
Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest for the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occurre in T. urticae populations in fieldgrown strawberries? 2) How and where does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) How and where does N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to overwinter as both hyphal bodies in hibernating T. urticae females from October to at least February at temperatures as low as -20o C. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), preliminary results show that high numbers of spores (ca 1300-1900 per cadaver) were thrown at all three temperatures. Further, spores were thrown about the same distance (up to about 6 mm) at all three temperatures. The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempts to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.
Sammendrag
To obtain information that might help in the use of Neozygites floridana (Zygomycetes: Entomopthorales) in biological control of Tetranychus urticae (Acari: Tetranychidae), in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occur in T. urticae populations in field grown strawberries? 2) How does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) Where do N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to over-winter as hyphal bodies in hibernating T. urticae females throughout the winter. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), results show that the highest numbers of spores (1886 and 1733 per cadaver) were thrown at 13o and 18o compared to 23o C (1302 per cadaver). Spores were thrown at the same distance (up to about 6 mm) at all three temperatures when cadavers were placed with dorsal side facing up. Cadavers placed with dorsal side down (hanging) threw equal numbers of spores up (on the underside of the leaf in nature) and down (on the leaf below). The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempt to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Poinsettia (Euphorbia pulcherrima Willd. Ex Klotzsch), is a contemporary symbol of Christmas in most parts of the world. Today, Europe and North America represent the largest volume of production and sales, but demand is growing quickly in the other regions as poinsettia becomes more popular each year. In Norway, poinsettia is one of the most important pot plants, with a yearly production close to 6 million plants. Its ornamental value and innovation potential have laid the foundation for extensive research in Norway and elsewhere. Two viruses i.e. poinsettia mosaic virus (PnMV) and poinsettia cryptic virus (PnCV) can cause diseases in modern poinsettia cultivars. PnMV gives visible symptoms in poinsettia during parts of the growing season. Growers show great interest in the potential benefits of growing PnMV-free poinsettias. Traditionally, PnMV-free poinsettia plants were obtained by in vitro culture of apical meristems. However, this is a time-consuming method and the regenerated new PnMV-free poinsettia has sometimes lost the branching characteristic which is important for poinsettia. We have therefore developed an Agrobacterium-mediated transformation approach for poinsettia. Using this method, we have produced transgenic poinsettia with improved resistance against PnMV by expressing three hairpin (hp) RNA gene constructs which targeted various regions of the virus genome. Molecular analyses have confirmed the stable integration of transgenes into the poinsettia genome. This is the first report describing Agrobacterium-mediated transformation of poinsettia. The PnMV resistant transgenic poinsettia lines produced are of commercial potential. The methodology developed could also facilitate the further improvement of this ornamental plant with the aims of enhancing its disease resistance, quality traits, desirable colour and ornamental value. We have also transformed N. benthemiana to reveal the relationship of different vector constructs and the RNA silencing mediated PnMV resistance. This result will imrpove our understanding of RNA silencing mediated resistance through genetic engineering.
Forfattere
Solveig HaukelandSammendrag
De fleste av oss har, enten vi har hage, dyrket mark eller ferdes i skog og mark, hatt befatning med iberiaskogsneglen, brunsneglen, mordersneglen, rambosneglen. Mange navn på en etter hvert velkjent skapning i hagene våre. Sneglene tar godt for seg av plantene blomsterbedet, og man kvier seg for å gå barbeint over en duggfrisk villaplen en sen sommerkveld. Salat- og jordbærbøndene har ennå mer å frykte, eller? Foredrag om iberiaskogsnegl levesett og bekjempelse.
Forfattere
Solveig HaukelandSammendrag
Entomopathogenic nematodes (EPNs) are commercially available for control of soil dwelling larvae of the vine weevil (Otiorhynchus sulcatus). In Europe several products are available comprising three different species, Heterorhabditis bacteriophora, H. megidis, and Steinernema kraussei. The latter species is for use at low temperatures. Results from several trials using H. megidis and S. kraussei against vine weevil in strawberry fields indicate that low temperature, soil type and possibly the application method are limiting factors that appear to reduce their efficacy. The use of EPNs against vine weevil larvae in the field will be discussed including results from cold-activity studies and application methods.
Forfattere
Solveig HaukelandSammendrag
The large arionid slug Arion lusitanicus is a serious pest in parts of northern Europe including many parts of Norway. In Norway it has mainly been a pest in home gardens but in recent years it has also spread to horticultural and vegetable crops such as strawberry and lettuce. The use of the nematode Phasmarhabditis hermaphrodita against A. lusitanicus is being investigated in an on-going research project that was initiated in 2005. A survey was conducted in 2004 to examine if the nematode P. hermaphrodita could be found occurring naturally in Norway. The result of the survey was positive which led to registration of the product Nemaslug in 2005. Several experiments have been carried out since 2005, to study the effect of both the commercial product Nemaslug and Norwegian isolated P. hermaphrodita on A. lusitanicus slugs. Laboratory and controlled pot experiments confirm that young stages of the slugs are susceptible to the slug parasitic nematode. Further work on the infection process of nematodes in slugs as well as the practical aspects of nematode use in gardens and the field will be addressed as a next step in these studies.
Forfattere
Solveig HaukelandSammendrag
Fra tid til annen gulner plenen og andre grøntarealer uten at noen synlig grunn foreligger. Årsaken til gulningen kan være oldenborrelarver. Artikkelen beskriver problemet med oldenborrer i plen og om bekjempelse.
Tidsskriftspublikasjon – 2007 - Det store snegleåret
Jorunn Amdal, Arild Andersen, Solveig Haukeland
Sammendrag
Snegler har vært det store samtaleemnet på Hageselskapets nettprat i sommer. En kjølig og ikke minst fuktig sommer i sør, har ført til at snegleplagen nærmest har eksplodert mange steder i landet. Artikkelen er i form av et intervju av Arild Andertsen og Solveig Haukeland om snegler og deres bekjempelse.
Sammendrag
Different methods to reduce the population of Arion lusitanicus are being investigated in private gardens naturally infested with the slug. In the laboratory the effect of different mulches are also being tested. Preliminary results from the studies conducted in gardens indicate that physical removal of slugs by picking or trapping and killing is most effective. In arenas in the laboratory, slugs avoided cocoa chips mulch and alginate granules. These studies are on-going and will be completed at the end of 2008. The slug parasitic nematode Phasmarhabditis hermaphrodita has recently been isolated in Norway. It is being studied as a biological control agent of A. lusitanicus. Results so far show that young slugs (0,02 " 0,04g) are most susceptible to infection and death. It also appeared that soil based bioassays gave better and more consistent results than assays using Petri dishes with filter paper. Further studies on the host-parasitic relationship of the nematode and slug are required.