Control of Late Blight of Tomato and Potato by Oilgochitosan

Choi, Yong Ho; Choi, Gyung Ja; Kim, Byung Sup; Jang, Kyoung Soo; Yoon, Mi Young; Park, Myoung Soo; Kim, Jin Cheol

Research in Plant Disease 2011;17(2):129-135.
Published online August 30, 2011.

올리고키토산에 의한 토마토 역병과 감자 역병의 방제

최용호, 최경자, 김병섭, 장경수, 윤미영, 박명수, 김진철

Control of Late Blight of Tomato and Potato by Oilgochitosan

Yong Ho Choi, Gyung Ja Choi, Byung Sup Kim, Kyoung Soo Jang, Mi Young Yoon, Myoung Soo Park, Jin Cheol Kim

Abstract

Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine and Nacetyl- D-glucosamine. There have been many reports on the induced systemic resistance and in vivo antifungal activities of higher molecular weight chitosans with molecular weights over 3,000 amu (atomatic mass unit), but there are few papers on in vivo antifungal activities of low molecular weight chitosans (oligochitosans) with molecular weights less than 3,000 amu. In our study, an oligochitosan sample (320?3,000 amu) showed a potent 1-day protective activity with control values more than 94% at concentrations of 500 and 1,000 ?g/ml especially against tomato late blight caused by Phytophthora infestans under growth chamber conditions. It also displayed a moderate 1-day protective activity with control values of 67?89% at concentrations of 500 and 1,000 ?g/ml against wheat leaf rust and red pepper anthracnose. On the other hand, it showed a 16-hr curative activity against red pepper anthracnose, but not against tomato late blight and wheat leaf rust. In field experiments, oligochitosan effectively suppressed the development of late blight on potato and tomato plants with control values of 72% and 48%, respectively. The results strongly indicate that oligochitosan can be used as an eco-friendly organic material for the control of late blight on tomato and potato plants.

Key Words: Control, Oligochitosan, Organic material, Phytophthora infestans, Tomato Late blight