First report of a potato cyst nematode, Globodera rostochiensis, on potato, in Iran

In June 2008 a few ware potato fields in Hamadan Province in the western part of Iran showed patches of about 20-200 m2of poor growth. Potato plants in these areas exhibited symptoms of severe stunting and nutrient deficiency along with yellow leaves and wilting (Fig. 1). Roots of infested plants showed white, golden mature females and brown cysts on their surface (Fig. 2). Cysts and second stage juveniles were extracted from soil and root samples.

The morphological and morphometrical characters of second stages juveniles and perineal area of cysts were examined by light microscope. The cysts showed the general characteristics of Globodera genus i.e. almost spherical body without vulval cone, circumfenestrate opening of the perineal area and subterminal anus, with the distance from anus to the vulval basin (n=25) 49.56 ± 9.68 (32-68) µm, the vulval basin diameter 15.24 ± 1.92 (10-17) µm, the Granek's ratio 3.27±0.61 (2.25-4.47), and the number of cuticular ridges between anus and vulval basin (n=16) 19±2.5 (15-24). Second stage juveniles (n=16) had stylet length 21.12±0.95 (20-23) µm with rounded knobs, tail length 52.7±2.9 (48-57) µm, and hyaline part of tail 28.12±3.53 (20-33) µm.

A molecular test was done for complementary diagnosis. DNA was extracted from several single cysts as described by Tanha Maafi et al. (2003) and amplified by species specific primers (Fullaondo et al., 1999). On the basis of the results obtained the cysts were identified as Globodera rostochiensis [Wollenweber, 1923 (Behrens, 1975)] (Wouts & Baldwin, 1998; OEPP/EPPO. 2004). The morphological diagnosis was confirmed by amplifying a single fragment of 315bp length which corresponded with Fullaondo et al., 1999. No amplification was produced with the specific primers for G. pallida. Potato cyst nematodes (PCNs) are considered quarantine pests in Iran and this is the first report of the genus Globodera and G. rostochiensis from Iran.