Nematodes (roundworms) are microscopic worms living in the water films surrounding the soil particles. Nematodes are the most common multicellular animals on planet Earth. Free-living plant-parasitic nematodes move freely in soil attacking roots externally and internally. Crops attacked by nematodes may develop patches of poor growth and low yield due to root damage and malfunction in the up-take of water and nutrients.
The aim of the project is to study the involvement of nematodes in growth disturbances of different crops using, among others, aerial photography from a drone. Growth disturbances will be correlated with nematode densities through soil sampling in different crops. Data from Norway will be included in the already-exisiting EU project Best4Soil (https://www.best4soil.eu) that will be licenced and adjusted for Norwegian conditions. Best4Soil is a database with information on plant-parasitic nematodes, their hosts and their reproduction rates on different host plants. The data will be used by Norwegian growers to decide which crops to grow to eliminate unwanted nematodes.
Soil samples have been collected in several fields and crops at different locations for the past three years. Samples have been collected in the beginning of the growing season and from potato, onions and wheat. Soil samples have also been collected at the end of the growing season with emphasis on the important crops like potato and carrot. Drone images from all fields were collected in the beginning of the season (April/May), and in June and July, with two different cameras, giving rise to images showing plant health status. Several genera of plant-parasitic nematodes were detected in the samples, namely lesion nematodes, stubby-root nematodes, root-gall nematodes, potato cyst nematode and stunt nematodes. Preliminary results indicate that root lesion nematodes do little damage to potato.
Further information on nematode status has been obtained through isolation and analysis of gene material (DNA) from 94 individual free-living plant-parasitic nematodes. In collaboration with Norwegian Agricultural Extension Service (Norsk Landbruksrådgiving), soil samples were taken from carrot fields in the counties: Viken in the east, Rogaland in the west and Troms in the north, at planting and at harvest. The samples were analysed for plant parasitic nematodes. The aim of this study is to determine the nematode densities (and species) under carrot production. Results are in progress. In a carrot field in Karmøy (west Norway) the spiral nematode species Rotylenchus robustus was detected for the first time in Norway. Much damage was observed in this field and studies are planned for 2022 to determine if R. robustus is the cause. Reproduction factors have been calculated for the different groups of plant-parasitic nematodes in the four fields.
Use of soil treatment combined with crop rotation has been performed to study the effect of different types of fertilizers in different types of plant parasitic nematodes. Field trials have been conducted in cooporation with the Norwegian Agricultural Extension Service (Norsk Landbruksrådgiving). The following treatments were included in the trials: cow manure, pig manure (wet fraction), pig manure (dry fraction), chicken manure (pellets) and a chitin based product from mussels, in addition to a control treatment without manure, but with synthetic fertilizer. The aim of the trials was to investigate the effect of different types of manure that may indirectly have an effect on the population densities of key plant-parasitic nematodes, among others, in crops of barley. Preliminary results suggest that there are only small differences in effect of the different treatments. However, the results may be masked by high densities of nematodes. The data are being further processed and experiments in greenhouse will be performed in the last phase of the project to better control the amounts of nematodes in the samples.
In a greenhouse experiment, several growth promoting products were tested on strawberry plants to determine if such amendments would increase the plants tolerance to needle nematode. Strawberry seedlings (plugs) were planted in pots containing soil naturally infested with needle nematode. Plant weight and yield was recorded, and the pots analysed for nematodes. Results are being processed.
Free-living plant parasitic nematodes are microscopic round worms that move freely in soil feeding on roots. Soil samples indicate an increasing damage from free-living nematodes in Norway. Yield losses of up to 50 % have been noted in local fields, and indeed some farmers have considered abandoning crop production on nematode infested land. Because of this, methods of efficient nematode management have been sought for both in the extension service and among farmers.
The main objective of this project is to increase and improve the current knowledge on the occurrence and management of free-living nematodes in potato, vegetables, strawberry and cereals in Norway.
Nematode damage shows as patches of poor plant growth and this project will combine nematode patch dynamics and remote sensing with drone technology, and image analysis to estimate damaging thresholds and reproductive factors of free-living plant parasitic nematodes on selected plants in the field. The effect of soil amendments with organic waste, compost and silicone in nematode management will also be investigated. An important aim is also to strengthen, develop and maintain the national competence in Norwegian nematology by training a PhD student.
Collaborators in this project are a) The Norwegian Agricultural Extension Service (NLR); b) University of Hertfordshire School of Life and Medical Sciences; Chinese Academy of Agricultural Sciences; and The Julius Kühn-Institut Germany.
Dissemination will be conducted via open days with field demonstrations, publications in (technical) journals in cooperation with NLR and on their website and in meetings with farmers.
Results from the project will increase the competence on free-living plant-parasitic nematodes in NIBIO, the extension service and among farmers. Successful nematode control will decrease the current loss in yield and quality of Norwegian produce and be to the economic benefit of both wholesalers and retailers.