Abstract: DL-β-aminon-butyric acid ( BABA) that was applied as a foliar spray to pepper plants induced resistance to a challenge infection with Phytophthora capsici . A relatively high concentration of BABA at 1 000 g/mL, which had no antifungal activity in vitro against P . capsici , was required to induce resistance against Phytophthora blight with a foliar and stem spray, thus leading to complete control of the disease. About 3 days interval
between BABA􀀁treatment and challenge inoculat ion was sufficient to induce resistance in pepper plants, and the in duced resistance could be retained more than 20 days after BABA􀀁treatment. High inoculum levels of P . capsici
caused Phytophthora development slowly in pepper foliar treated with BABA, especially at early plant growth stage, which suggests that the induced resistance in pepper plants may be more quantitative rather than qualitative.

Key words: Pepper, Phytophthora blight, BABA, Induced resistance