No abstract

Treatment of pepper plants with the nonprotein amino acid, DL-13-amino-n-butyric acid (BABA) induced resistance to subsequent infection by Phytophthora capsici. In contrast, the c~-, and v-isomers of aminobutyric acid were ineffective as inducers of resistance. A relatively high concentration of BABA at 1,000 #g ml-I, which had no antifungai 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 1 day interval between BABAtreatment and challenge inoculation was sufficient to induce resistance in pepper plants. High inoculum levels of P. capsici caused Phytophthora development slowly in pepper stems 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. BABA applied to the root system also protected pepper stems from P. capsici infection.