Investigations into the Roles of Fertilizer Level and Irrigation Frequency on Growth, Quality, and Severity of Pythium Root Rot of Peperomia obtusifolia

Abstract

Abstract Peperomia obtusifolia (L.) A. Dietr. were grown with various fertilizer levels (0.5–3.5 g Osmocote 19-3-10/10-cm pot) and irrigation frequencies (1, 2, or 3 times/week). Plants were inoculated with Pythium splendens Braun 2–6 months after initiation of fertilizer treatments. Top and root quality responses were linear and quadratic with respect to fertilizer level. One month after inoculation, root quality decreased the most for plants with the highest irrigation frequency and the lowest fertilizer level. Plants fertilized at the highest rate did not show a significant decrease in root quality. There was an interaction between fertilizer and irrigation rates as measured by plant height, quality, and disease ratings. Poorest quality plants resulted when watered 3 times/week and fertilized with 0.5 g Osmocote/pot. Highest quality plants resulted when watered 2 or 3 times/week and fertilized with 2.5 g Osmocote/pot.