Organic and synthetic fertilizers were evaluated under three irrigation regimes (daily, twice weekly, and rain only) for management of necrotic ring spot (Leptosphaeria korrae Walker & Smith) of Kentucky bluegrass (Poa pratensis L.). Disease severity varied due to fertilizer and irrigation treatments. After 2 years of treatments, daily irrigation reduced disease incidence as compared to twice-weekly irrigation, while organic fertilizer, as a feathermeal-bonemeal-soybeanmeal mixture, when applied monthly at 48.8 kg N/ha, reduced disease incidence as compared to urea fertilizer. For 2 of 3 years, differences in disease incidence were attributable to irrigation treatments, and after 4 years, all N fertilizers reduced disease incidence as compared to no fertilizer.
Dept. of Botany and Plant Pathology and the Pesticide Research Center.Dept. of Botany and Plant Pathology and the Pesticide Research Center.