Abstract

Severity of Xanthomonas leaf spot of Pilea spruceana was highest for plants receiving intermediate fertilizer rates (recommended to 5 times the recommended rate) and decreased at rates of 6–9 times recommended rate. Plant growth responded similarly with highest quality plants most susceptible to Xanthomonas campestris. Tissue nutrient content for highest quality plants was as follows: N (2.2%), P (0.37–0.38%), K (1.2–1.4%), S (1.00–1.06%), Mg (1.03–1.24%), Ca (2.07–2.30%), Fe (62–76 mg/kg), Mn (358–370 mg/kg), B (50–55 mg/kg), Cu (10 mg/kg), and Zn (348–357 mg/kg). Leachate electrical conductivity for highest quality plants was approximately 200 μmhos/cm. The results indicate that optimizing the nutrient status for highest quality foliar growth of P. spruceana may result in conditions which maximize severity of Xanthomonas leaf spot.