A survey of free-living plant-parasitic nematodes associated with damage in carrot (Daucus carota var. sativus) fields in Norway

• Main Author: Tangvik, Marte Persdatter
• Format: Dissertation
• Language: English

Nematodes cause yield reduction in agriculture worldwide. In research, the main focus has been on cyst nematodes and root-knot nematodes and not so much on free-living plant-parasitic nematodes. Thus, the importance of free-living plant-parasitic nematodes is likely underestimated. The aim of this survey was to get an overview of free-living plant-parasitic nematodes in carrot (Daucus carota var. sativus) production, and their association with damage. Soil samples were collected from 19 fields in the carrot-producing regions of Norway where nematode damage was suspected. The samples were analysed for free-living plant-parasitic nematodes. The analyses showed that free-living plant-parasitic nematodes occur frequently in carrot fields in Norway. Root lesion nematodes (Pratylenchus spp.) were the most frequently occurring genus and P. crenatus the most frequently occurring species. Symptoms of nematode damage were observed in all the samples where taproots were received for analysis. Symptoms observed in this survey include, but are not limited to, necrotic spots, forked taproots, split taproots, short taproots and taproots with galls. In fields with a high occurrence of Longidorus spp. and Xiphinema, growth of carrots seems to be severely disturbed. Geographical distribution of Xiphinema spp. seems to be limited to the south of Norway.