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.
2016
Sammendrag
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Forfattere
Agnar KvalbeinRedaktører
Nina TrandemSammendrag
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Forfattere
R. Venancio G.J. Moraes R.C. Castilho N.S. Iwanicki G.F. Moreira Lise Grøva Karin Westrum Ingeborg KlingenSammendrag
Tick-borne diseases, such as anaplasmosis and babesiosis, are of major concern for Norwegian sheep farmers. Ticks can be controlled on and off the host, usually with the long-term, high-rotation use of chemicals. Fungal pathogens, predatory mites and ants are thought to be important tick killers in nature. However, the prevalence and diversity of predatory mites in tick habitats has barely been evaluated. It is known that most soil mite species of the cohort Gamasina (order Mesostigmata) are predators. Until now, 220 mesostigmatid species have been reported from Norway, most of them belonging to the Gamasina. One of the first recommended steps in a biological control program involves the determination of the fauna in the pest habitat. The objective of this study was to determine the groups of gamasines co-occurring with I. ricinus in sheep grazing areas in Isfjorden and Tingvoll in Western Norway. A total of 2,900 gamasines of 12 families was collected. The most numerous families were Parasitidae (46.9%) and Veigaiidae (25.7%), whereas the most diverse families were Laelapidae, Macrochelidae, Parasitidae and Zerconidae. Our results showed that the tick density was significantly related only to locality, elevation and rainfall. Differences in the prevailing environmental conditions resulted in more outstanding differences between Gamasina abundances than diversities. Based on our present knowledge of the potential of different gamasine groups as biological control agents, the results suggested that laelapid mites should be among the priority groups to be further evaluated for their role in the natural control of I. ricinus in Norway.
Sammendrag
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Sammendrag
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Sammendrag
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Forfattere
Anne-Kari Holm Inger Sundheim Fløistad Knut Asbjørn Solhaug Benedikte Watne Oliver Lars Olav BrandsæterSammendrag
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Sammendrag
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Sammendrag
The success of precision agriculture relies largely on our ability to identify how the plants’ growth limiting factors vary in time and space. In the field, several stress factors may occur simultaneously, and it is thus crucial to be able to identify the key limitation, in order to decide upon the correct contra-action, e.g., herbicide application. We performed a pot experiment, in which spring wheat was exposed to water shortage, nitrogen deficiency, weed competition (Sinapis alba L.) and fungal infection (Blumeria graminis f. sp. tritici) in a complete, factorial design. A range of sensor measurements were taken every third day from the two-leaf stage until booting of the wheat (BBCH 12 to 40). Already during the first 10 days after stress induction (DAS), both fluorescence measurements and spectral vegetation indices were able to differentiate between non-stressed and stressed wheat plants exposed to water shortage, weed competition or fungal infection. This meant that water shortage and fungal infection could be detected prior to visible symptoms. Nitrogen shortage was detected on the 11–20 DAS. Differentiation of more than one stress factors with the same index was difficult.
Forfattere
Yordanys R. González Orelvis Portal Erik Lysøe Annarella Chea Luis Rojas Nicolai Meyling Ingeborg KlingenSammendrag
The aim of this study was to evaluate the effect of conventional versus organic common bean (Phaseolus vulgaris) production on natural occurrence of Beauveria spp. as entophytes in bean plant tissue, from soil and as infections in stink bugs (Hemiptera: Pentatomidae), an important pest of bean in Cuba. Twenty-four organic and conventionally managed bean fields were sampled from September 2014 to April 2015 and Beauveria spp. were isolated and DNA extracted. PCR amplification of the intergenic Bloc region was performed for the identification of Beauveria species. Eighty-seven isolates were obtained from the soil samples by using the Galleria mellonella baiting technique. Further, 45 isolates were obtained from endophytic tissues of bean plant parts and 18 isolates were acquired from stink bugs. Only Beauveria bassiana was identified by DNA sequencing in this material. B. bassiana was more prevalent in soil, plant and stink bugs sampled from organic fields (41% soil, 22% plant, 9% bugs) compared to conventional fields (17% soil, 8% plant, 2% bugs). All plant parts were colonized by B. bassiana, but a significantly higher occurrence of this fungus was found in roots (9%) compared to stems (6%), leaves (4%) and pods (2%) in organic fields. In conventional fields there was a significantly higher occurrence of B. bassiana acquired from root (4%) and stem (3%) compared to leaves (1%) and pods (1%). Mating type PCR assays revealed that each of the isolates carried single mating types, with frequencies of 146/150 (MAT1) and 4/150 (MAT2), indicating limited potential for recombination. Our findings show that B. bassiana occur naturally as endophytes in bean fields in Cuba and contribute to a better ecological understanding of B. bassiana in agriculture.