Effects of Nitrogen Level and Osmotic Pressure of the Nutrient Solution on Incidence of Puccinia graminis and Helminthosporium sativum Infection in Merion Kentucky Bluegrass¹

Abstract

Synopsis Merion bluegrass grown in solution culture produced lower yields of foliage under low levels of nitrogen and high levels of osmotic pressure than when treated with high nitrogen and low osmotic pressures. Turf was resistant to inoculation with Puccinia graminis Pers. at all treatment combinations. Numbers of Helminthosporium sativum Pammel, King, and Bakke lesions per leaf blade and average size of lesions increased with increasing levels of nitrogen and decreasing osmotic pressure.