The yam nematode, Scutellonema bradys, a new theat to potato

We investigated the possible threats of Scutellonema bradys on potato production by evaluating the host suitability and damage symptoms in five potato varieties grown in Europe and Africa. The probability of nematode entry, spread and establishment in Europe was also investigated, through a pest risk analysis (PRA). Inoculation of sprouted potato tubers with S. bradys in pot tests caused varying levels of damage to the different potato varieties, when these were evaluated 8 weeks later. The nematode infected roots and tubers, causing scaly surface appearance of tubers, brown root lesions and tuber rot. The number of nematodes recovered from roots, tubers and soil was greatest on Desiree, Spunta and Nicola, while reproduction was low on Diamant and Draga. The PRA showed that the likelihood of importation of S. bradys from third countries into the EU is high due to the import of contaminated yam tubers from infested African regions. However, the likelihood that nematodes reach susceptible hosts is considered low; therefore, “entry”, as defined in a PRA, is low. Nematode establishment is possible on hosts like yam, potato and tomato in southern parts of the EU. Nematode spread, in the EU and Africa, occurs through several pathways: yam and potato tubers, peels, soil from infested areas attached to plants or equipment, and travellers carrying plant parts or soil. The study demonstrated that S. bradys can damage potato and highlighted the need to reduce the risk of nematode entry and spread in the EU region, as well as in Africa.