Creeping Bentgrass Nitrogen and Brown Patch Interactions.

Creeping bentgrass (Agrostis stolonifera L.) is tolerant of short mowing and high traffic, but these conditions increase pathogen susceptibility. A prevalent disease on bentgrass golf course greens and tee boxes is Brown Patch (Rhizoctonia solani). One potential component of integrated pathogen management is correct nitrogen (N) fertilization. Bentgrass was grown in a chamber hydroponically at deficient, optimum, and excessive levels of N (2.5, 10, and 80 mM) with or without Rhizoctonia inoculation and grown for 42 d. Not surprisingly, increasing solution N resulted in increased shoot and decreasing root biomass. Rhizoctonia inoculation did not appear to dramatically impact biomass. However, infection resulted in near total necrosis of all tissues at the low rate of N for inoculated plants, but plants at higher N rates and those not inoculated were healthy. The project will be concluded following another study with Rhizoctonia and PCR analysis of the roots and crowns from both studies.