Quarantine pest discovered in tomato seeds

All forms of plant material can contain several types of potentially harmful organisms, such as fungi, viruses, insects, bacteria, and nematodes. Importing plant material into Norway therefore poses a risk of introducing new, harmful organisms to the country.

Through the StopPest project, researchers at NIBIO are working to assess this risk. They have looked at possible diseases found in seeds sold at garden centres.

In tomato seeds, an unwelcome surprise was hidden: the quarantine pest "potato spindle tuber viroid." The viroid can cause significant yield losses in both potato and tomato production but is primarily considered a threat to tomato production in greenhouses. According to the Norwegian Food Safety Authority, it has not yet been detected in either tomato or potato production in Norway.

"This is a serious finding," says Dr Dag-Ragnar Blystad and Dr Zhibo Hamborg, who work with plant viruses at NIBIO.

"We also found seeds with tomato mosaic virus. Although this virus is not a quarantine pest, it causes significant damage to the plants. Both diseases spread easily on contact. Thus, even a low infection rate in a greenhouse can be serious."

Although the finding of "potato spindle tuber viroid" was not made in seeds sold to professional tomato growers, we must take the finding seriously. It has been documented that tomato seeds were tested for the viroid before being imported into Norway. This suggests that current testing of seeds before sale is not adequate.