Phytosanitary risks of newly introduced crops (PRONC)

Some consumers and pioneering growers show a growing interest in the edible tubers yacon, ulluco, batat (a kind of sweet potato), crosne, mashua, oca and the so-called "forgotten vegetable" Jerusalem artichoke. These are niches in a relatively new market, where there are few plant disease studies or food safety rules. The plant material (the seed, the nodules, the cuttings) that sometimes come from exotic destinations or via internet orders into the country can easily introduce new pests and diseases. This project therefore posed an essential question with a phytosanitary impact: what can be done in the introduction of unprecedented/new diseases when these crops are grown in the vicinity of the ' traditional ' commercial crops?

The project addressed the following questions, focusing on tuber producing crops which are vegetatively propagated (i.e. yacon, ulluco, sweet potato, crosne, mashua, oca and Jerusalem artichoke). An inventory was drafted on which of these crops were cultured in Belgium and where (including different cultivars). What was the origin of the planting material and how was it imported (assessement of the introductory routes). In a next phase, the status of the viruses and nematodes that were associated with propagation materials, in the field and in the marketed new (tuber) crops was evaluated. Finally, the phytosanitary risks of these organisms was assessed, and the phytosanitary measures assisting in limiting the introduction and distribution of some of these high risk viruses and nematodes were listed. 

The inventory of pathogenic viruses and nematodes on the newly introduced tuber crops provides a better insight in the risk that these pathogens pose to the respective (exotic tuber) crops themselves and to other (related) host plants grown in Belgium. This knowledge was badly needed to support the phytosanitary measures imposed by the Belgian and EU authorities. The results of the project also promoted the general epidemiological knowledge on existing viruses and nematodes with a known phytosanitary risk as well as on new viruses for which little information is available in the literature to date. The European collaboration in the parallel transnational Euphresco project was also very relevant, for example, for the joint effort to set up biological characterization experiments for some of the new viruses to support a pest risk analysis.