An analysis method based on high-throughput sequencing was validated and applied to forty seed lots of Belgian or foreign origin, belonging to some thirty conifer species. The analyses carried out led to the identification of almost 500 fungal species, including pathogenic species never reported in Belgium, or even in Europe. Due to its very high cost, this method cannot yet be used for routine analysis. Furthermore, although the method can detect various pathogenic fungi in seed batches, the risk of transmission of the pathogen from the seed to the seedling (through the development of symptoms) still needs to be assessed.
Surveys were carried out with the competent authorities, nursery owners and foresters in both the north and south of the country. They highlighted the fact that certain seed lots, particularly of ornamental conifers, come from other continents (North America and Asia) and are therefore associated with a greater risk of introducing new diseases into our territory. They also showed that the rather complex regulations governing the conifer seed trade, which provide certain guarantees for the purchaser (identity of the woody species, genetic purity, origin), were often poorly understood by nursery owners. These surveys also revealed a lack of information on the origin of seeds in the catalogues of certain suppliers, which can lead to purchases of seeds from third countries without the buyer's knowledge. Another common practice in Belgium is the use of cultivation contracts, whereby customers, spread throughout Europe, supply a batch of seeds and receive seedlings from these seeds in return. This practice increases the quantity of seeds introduced into Belgium and the associated risk of introducing new diseases.
Financing:
Project funded by the Federal Public Service Public Health, Security of the Food Chain and Environment, contract no. RF 31/6344, ALERTSEED
Caption: Chamaecyparis lawsoniana seeds from Denmark
