The yam nematode (Scutellonema bradys), a newly emerging pest on potato.

The study investigated the possible threats of Scutellonema bradys on potato production by evaluating the host suitability and damage symptoms of the nematode on five potato varieties grown in Europe as well as in Africa. The probability of nematode entry, spread and establishment in Europe was also investigated by performing a pest risk analysis (PRA). Inoculation of potato with S. bradys in a pot test caused varying damage levels to the different potato varieties. The nematode infected both roots and tubers, resulting in scaly surface appearance of tubers, brown root lesions and tuber rot. The number of nematodes recovered from roots, tubers and soil was greatest for the varieties Desiree, Spunta and Nicola (2-fold population increase), while reproduction was low on Diamant and Draga, where practically no increase was observed (reproduction factors of 1.1 and 0.8, respectively). The PRA showed that the likelihood of entry of S. bradys from third countries into the European Union is high due to importation of contaminated yam tubers from infested regions of Africa, although reaching a susceptible host is less probable. Establishment of the nematode is possible on hosts like yam, potato and tomato, especially in the most southern parts of the EU. Spread of the nematode is likely through several pathways: tubers or peels of host plants, soil from infested areas or attached to equipment, and travelers carrying plant parts and/or soil samples. The study demonstrated that S. bradys can damage potato and highlighted the need to reduce the risk of nematode entry and spread in the European Union region, as well as in Africa.