1Central Potato Research Station, Model Town P.O. P.B. No.1. Jalandhar-144003 (Punjab).
2Central Potato Research Institute, Shimla-171001 (H.P.).
Incidence of pseudo common scab symptoms (PCS) on potato tubers was recorded from two field trials conducted at the Central Potato Station, Jalandhar, during 1992–93 to find the effect of rates of N. sources of N, Fe and cultivars on it. The incidence was positively and significantly correlated with the rate of N and was more in large sized tubers than medium and small sized tubers. Ammontum chloride alone or alongwith urea showed higher incidence of PCS symptoms (46–51%) than ammonium sulphate (39%), calcium ammonium nitrate (34%) and urea (30%). Application of ferrous sulphate (50kg/hal reduced the incidence of PCS from 81 to 58% in cv. Kufri Sindhuri but had no effect in other cultivars. The mean incidence of PCS was highest in cv. Kum Sindhuri (68%) folIowed by Kufri Chandramukhi (65%), Kufri Badshah (56%), Kufri Bahar (48%), Kufri Jyoti (34%), and Kufri Jawahar (19%). Higher concentrations of Ca and Mn but low concentration of Fe in tubers showed positive association with PCS symptoms.
