South Korea's agricultural agency said Friday it plans to expand surveillance on fire blight amid growing concerns over the nationwide spread of the deadly disease for apple and pear trees.

The move came as an apple farm in Andong, 268 kilometers south of Seoul, confirmed another case of fire blight, which marked the first infection to be reported from North Gyeongsang Province, according to the Rural Development Administration.

North Gyeongsang Province accounts for around 60 percent of South Korea's production of apples.

The agency is currently investigating trees within a 2-kilometer radius of infected farms.

Fire blight is a contagious plant disease that affects apples and pears. Leaves of infected trees become dry as if they were burned.

The country reported 231 cases of fire blight so far this year, with North Chungcheong Province taking up 137 cases, followed by Gyeonggi Province that surrounds Seoul with 49 cases. The combined size of affected farms is estimated at 108 hectares. (Yonhap)