Gyeongbuk Agricultural Research and Extension Services: Persimmon Yield Depends on 'Control of Cercospora Leaf Spot'

Prevention Should Be Done by Mid-July at the Latest

Acute and chronic types of round leaf spot disease.

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Gui-yeol] The Gyeongbuk Provincial Agricultural Research and Extension Services (Sangju Persimmon Research Institute) reported concerns about the spread of the persimmon tree disease ‘Dungeunmuni Nakyeopbyeong’ (Round Spot Leaf Fall Disease) due to the Korea Meteorological Administration’s long-term forecast indicating that after a prolonged period of high temperatures this summer, temperatures may suddenly drop around August.

The outbreak of ‘Dungeunmuni Nakyeopbyeong’ occurs in any persimmon cultivation area and causes significant damage every year.

Affected trees experience early leaf drop, fruit drop or fruit softening, and even if fruit drop does not occur, fruit enlargement is poor and sugar content decreases.

The chronic form of Dungeunmuni Nakyeopbyeong begins to appear from mid-September, showing reddish-brown spots inside the lesion with a black ring around it; over time, the ring turns green and the surrounding area gradually spreads red, causing leaves to fall.

The acute form starts occurring from late August, with irregular brown spots appearing on leaves, which then drop along with fruit drop.

This progresses faster than the typical Dungeunmuni Nakyeopbyeong and causes leaves to fall while still green, making it easy to confuse with nutrient deficiency.

The disease is severe when temperatures suddenly drop by 3 to 5℃ over a short period (1?2 days) after the summer heat ends. Last year, after the outbreak, leaves turned red and then suddenly dropped along with fruit, causing significant damage to farms.

If Dungeunmuni Nakyeopbyeong occurs, orchard management is most important. Since the trees are weakened by early fruit and leaf drop, nitrogen fertilizer application should be increased during basal fertilization to stabilize tree vigor.

Shin Yong-seup, Director of the Gyeongbuk Provincial Agricultural Research and Extension Services, emphasized that early occurrence of Dungeunmuni Nakyeopbyeong greatly affects crop yield, so thorough early management and timely control measures are requested to reduce damage.