Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2020
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Authors
Anna Filipiak Solveig Haukeland Kamila S. Zając Dorota Lachowska-Cierlik Bjørn Arild HattelandAbstract
A survey of helminths associated with terrestrial slugs focusing on the invasive Arion vulgaris and the native A. ater was conducted on populations from France, Germany, Netherlands, Norway and Poland. In total, 648 terrestrial slugs were collected from 18 sample sites, and identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. In addition to A. vulgaris and A. ater, also A. vulgaris/A. rufus hybrids and A. ater/A. rufus hybrids were collected. Helminth species were identified based on morphological features and sequencing of the 18S and ITS rDNA regions. The parasites included four nematode species: Alloionema appendiculatum, Angiostoma sp., Phasmarhabditis hermaphrodita, Entomelas sp., two trematode species: Brachylaima mesostoma, Eurytrema sp., and one cestode (tapeworm) species: Skrjabinia sp. Alloionema appendiculatum was the most common helminth in the investigated slug populations. Furthermore, we found higher prevalence of trematodes in the invasive A. vulgaris compared with the native A. ater, while differences in the prevalence for nematodes were not as clear.
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Authors
Selamawit Araya Kidane Beira H. Meressa Solveig Haukeland Trine Hvoslef-Eide Christer Magnusson Marjolein Couvreur Wim Bert Danny L. CoyneAbstract
Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being the most prominent genus present with a prominence value of 1460. It was present in each sample, with a highest mean population density per growing zone of 16 050 (10 g root)−1, although densities as high as 25 000 were observed in fields at higher altitudes in Guraghe (2200-3000 m a.s.l.). This lesion nematode is found in abundance in the cooler mountainous regions. Visible damage on the roots and corms was manifested as dark purple lesions. Using a combination of morphometric and molecular data, all populations were identified as P. goodeyi and similar to populations from Kenya, Uganda and Spain (Tenerife). Differences in population densities amongst cultivars indicate possible resistance of enset to P. goodeyi.
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No abstract has been registered
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The present study described a combining thermotherapy with meristem culture for improved eradication of onion yellow dwarf virus (OYDV) and shallot latent virus (SLV) from co‐infected in vitro‐cultured shallot shoots. In vitro‐cultured shoots infected with OYDV and SLV were thermo‐treated at a constant temperature of 36°C for 0, 2 and 4 weeks, and then meristems (0.5 mm) containing 1–2 leaf primordia were excised and cultured for shoot regrowth. Meristem culture without thermotherapy produced much higher levels of survival (100%) and shoot regrowth (55%) than those (62% survival and 32% shoot regrowth) produced by the procedure combining 4 weeks of thermotherapy with meristem culture. However, much higher virus‐free frequencies (70% for OYSV, 80% for SLV and 50% for both viruses) were obtained in the latter than those (10% for OYSV, 15% for SLV and 10% for both viruses) obtained in the former. Histological and subcellular studies showed that thermotherapy imposed stress or damage to the cells of meristems, thus resulting in reduced meristem survival and shoot regrowth. Studies on virus location revealed considerable alternations of virus distribution patterns in the thermo‐treated meristems. The results of histological and subcellular studies and analysis of virus distribution pattern added valuable experimental data in the combining thermotherapy with meristem culture for virus eradication. These data provided explanations as to why combining thermotherapy with meristem culture improved the eradication of OYDV and SLV from the virus‐infected in vitro shallot shoots.
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No abstract has been registered
Authors
Sophie Mentzel Merete Grung Knut-Erik Tollefsen Marianne Stenrød Roger Holten S. Jannicke MoeAbstract
No abstract has been registered
Authors
Gunda Thöming Sándor Koczor Ferenc Szentkirályi Hans Ragnar Norli Marco Tasin Geir Kjølberg KnudsenAbstract
In a field-trapping experiment with plant volatiles, we observed notably high attraction of green lacewing (Chrysotropia ciliata) males to the compound p-anisaldehyde. Based on this finding, we initiated the present study to elucidate this phenomenon and to investigate the chemical ecology of C. ciliata. Scanning electron microscopy revealed elliptical glands abundantly distributed on the 2nd to 6th abdominal sternites of C. ciliata males, whereas females of the species completely lacked such glands. No p-anisaldehyde was found in extractions of body parts of C. ciliata. Methyl p-anisate and p-methoxybenzoic acid were identified exclusively in the extract from abdominal segments 2–8 of males. Field-trapping experiments revealed no attraction of C. ciliata to either methyl p-anisate or p-methoxybenzoic acid. In contrast, males showed marked attraction to p-anisaldehyde in the field and antennae showed strong responses to this compound. Headspace collections in the field from living insects in their natural environment and during their main daily activity period indicated that p-anisaldehyde was emitted exclusively by C. ciliata males. Our overall results suggest that p-anisaldehyde might serve as a male-produced pheromone that attracts conspecific C. ciliata males. Here, we discuss hypotheses regarding possible mechanisms involved in regulation of p-anisaldehyde production, including involvement of the compounds methyl p-anisate and p-methoxybenzoic acid, and the potential ecological function of p-anisaldehyde in C. ciliata.