Potato cyst nematodes (PCN), Globodera rostochiensis and G. pallida, are a serious threat to potato crops worldwide. Due to the risk these two species pose, a national survey was implemented starting in 2010 aiming to know the presence and distribution of these quarantine nematodes in Portugal. This fact has led to an increasing demand to accurately identify the PCN species present in the fields. Usually, the identification is based on morphology followed by molecular analysis. Considering there is at least one laboratory in the EU certified for morphological identification of PCN, the aim of this study was to look into the possibility of using only morphological diagnostic characters for routine purposes. Forty cysts of Globodera were used, for morphological and molecular analyses. Morphological analysis allowed the identification of 23 cysts as G. rostochiensis and 17 cysts as G. pallida and the molecular results revealed that 9 cysts were G. rostochiensis and 31 cysts were G. pallida. Thus, morphological and molecular analyses matched 65%, concluding that in our routine analyses only an initial morphological approach followed by molecular methods enables a reliable identification of PCN species. So, it is recommended to combine both methods. PCR can be ruled out only if the purpose is to detect Globodera nematodes, which is the case of the seed potato fields where the presence of round-cyst nematodes will interdict the seed production.

Revista de Ciências Agrárias, vol. 41 n.º spe (2018)