Occurrence of rust on hazel nut (Corylus avellana L.)

摘要

Hazel nut (Corylus avellana L.) is a temperate zone nut crop mostly grown in European countries. In India, It is found growing wild on high hills in states of Himachal Pradesh and Uttaranchal. In Himachal Pradesh, a bud wood orchard of three cultivarsnamely, Tonda Romana, Tonda Giffoni and Tonda Gentile Delle Langhe has been established since 2000, at The Regional Research Station, Sharbo, distt. Kinnaur (H.P.)- On the plants of all the three cultivars rust disease was noticed during 2003 (Anonymous, 2004). Bright orange coloured rust pustules appeared on the lower leaf surface during the month of September. On upper surface light brown coloured necrotic area developed opposite to the rust pustules. The intensity of the disease on different cultivars was observed on 0-5 scale and the disease index calculated as per the formula of McKinney (1923) was recorded maximum (21.33 %) on cultivar Tonda Giffoni followed by Tonda Romana (19.67%) and minimum (11.67%) on cultivar Tonda Gentile Delle Langhe. Microscopic observation of the diseased samples revealed that the uredinia were sub-epidermal in origin, with peridium, opening by a pore delimited by differentiated ostiolar cells.