Occurrence of Gray Mold on Yacon Caused by Botrytis cinerea

Kim, Jeom Soon; Lee, Young Gyu; Kim, Su Jeong; Hong, Sung Kee; Choi, Hyo Won

Research in Plant Disease 2010;16(3):316-319.
Published online December 30, 2010.

Botrytis cinerea에 의한 야콘 잿빛곰팡이병의 발생

김점순, 이영규, 김수정, 홍성기, 최효원

Occurrence of Gray Mold on Yacon Caused by Botrytis cinerea

Jeom Soon Kim, Young Gyu Lee, Su Jeong Kim, Sung Kee Hong, Hyo Won Choi

Abstract

The gray mold disease occurred on tuberous roots of yacon in storage facilities in Gangneung, Korea, in March 2010. Symptoms typically appeared as in the form of dark brown discoloration on the surface of tuberous roots and water-soaked brown lesions in cross sections of the affected portions. A total of five isolates of Botrytis sp. were obtained from the symptomatic portions. All isolates on potato-dextrose agar (PDA) produced abundant conidia which were pale brown, one-celled, mostly ellipsoid or ovoid in shape and 8.2~14.8×6.5~9.9 μm in size. Large numbers of round to irregular, smooth, black, hard sclerotia were produced on PDA over time. The optimal temperature for mycelial growth and sclerotia formation of the fungal isolates was 20oC. On the basis of morphological and cultural characteristics, all the fungal isolates were identified as Botrytis cinerea. Pathogenicity test on host plants showed that the fungus could infect not only tuberous roots but also leaves and petioles of yacon. This is the first report on gray mold of yacon (Smallanthus sonchifolius) caused by Botrytis cinerea in Korea.

Key Words: Botrytis cinerea, Gray mold, Yacon (Smallanthus sonchifolius)