Vinegar has been considered as a potential organic herbicide, but more knowledge is needed about acetic acid concentration, application volume and use of adjutants on weed control. In this study, we determíned optímum acetic acid concentration and spraying time on several weed species. Vinegar is more effective in broadleaf weeds than grasses. Vinegar is also effective in controlling younger weeds such as 3rd weeks to 4th weeks after emergency. For example, 3rd weeks after emergency weeds were easily controlled at 2-3% of vinegar solution. But 4th weeks after emergency weeds were controlled at 4-5% of vinegar. Therefore vínegar concentration was recommended about 5%, and application time was when the weeds were young - within 31eaf stage.

• B.M. Lee(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• H.J. Jee(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• C.S. Kim(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• S.B. Lee(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• H.S. Nam(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• C.K. Kang(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• J.H. Lee(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)
• M.K. Hong(Organic Agriculture Div., National Academy of Agricultural Science, RDA, Suwon City, 441-707, Republic of Korea)