HTS as a powerful tool to assist the assessing the phytosanitary risks, associated with newly introduced tuber crops in Belgium

The increasing introduction of new exotic crops in Europe are an opportunity for growers to produce for niche markets. These new crops, as well as “forgotten” crops, are mainly grown and marketed outside the general, large-scale commercial agriculture. This local production, and its associated short food supply chain, obtain planting materials (seed, tubers, cuttings) and products from different sources. The phytosanitary status of these materials is very rarely checked. Entry and spread of possible plant pathogens and pests could pose a threat to traditional crops, besides hampering the cultivation of the new crops. Especially when planting material is obtained from non-European countries, phytosanitary risks can be high. We present the results of a project focusing on viruses and nematodes – both holding a high potential of being introduced without being noticed - in yacon (Smallanthus sonchifolius), ulluco (Ullucus tuberosus), sweet potato (Ipomoea batatas), crosne (Stachys affinis), mashua (Tropaeolum tuberosum), and oca (Oxalis tuberosa) as new crops, and Jerusalem artichoke (Helianthus tuberosus) as a forgotten crop in Belgium. Together with classic detection techniques, HTS is used to conduct an unprejudiced mapping of the presence of high risk viruses, particularly in starting material. A multitude of viruses were detected in small scale production units, and in tubers being traded through the internet, and this in any of the included tuber crops, in particular sweet potato. Currently, the phytosanitary impact of these viruses is being assessed, eg. for sweet potato chlorotic stunt virus (SPCSV), a regulated pathogen that is definitely present in some of the sweet potato starting material. In addition, the fact that viruses are so numerous in some of these tubers indicates that not much attention is paid to their presence when trading and propagating these crops. At least one virus, Physostegia chlorotic mottle virus (PhCMoV) is drawing our attention, since it is a relatively new virus for our region and has been reported to induce serious disease symptoms in tomato and pepper. Even if several Pratylenchus sp. were detected in some samples, no nematodes of major concern were found in tubers from the field nor in planting material. Although none of the Pratylenchus sp. have a quarantine status, and all are commonly found in Belgium, attention should be paid, as it can lead to damage on the tuber crops that were assessed.

Publication year:2022

Accessibility:Open