Open AccessDollar Spot Suppression on Creeping Bentgrass in Response to Repeated Foliar Nitrogen Applications
Author(s) -
Raymond J. Townsend,
Michael Millican,
Damon L. Smith,
Edward J. Nangle,
Kurt Hockemeyer,
Douglas J. Soldat
Publication year - 2021
Publication title -
plant disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.663
H-Index - 108
eISSN - 1943-7692
pISSN - 0191-2917
DOI - 10.1094/pdis-05-20-1031-re
Subject(s) - liberian dollar , ammonium nitrate , biology , nitrate , leaf spot , nitrogen , temperate climate , nitrogen fertilizer , calcium nitrate , ammonium sulfate , human fertilization , fertilizer , agronomy , zoology , horticulture , botany , medicine , chemistry , ecology , calcium , business , organic chemistry , finance , chromatography
Dollar spot is caused by the fungus Clarireedia spp. and is the most economically important disease of golf course turfgrass in temperate regions of the United States. Previous research has demonstrated that nitrogen (N) fertilization may reduce dollar spot severity, but the results have been inconsistent, and the impact of N as part of repeated foliar fertilization applications to golf course putting greens remains unclear. Two independent trials were replicated in Madison, Wisconsin and Glenview, Illinois in the 2015, 2016, and 2017 growing seasons. The objective of the first trial was to evaluate the effect of four different N rates applied as urea (4.9, 9.8, 19.4, and 29.3 kg N/ha applied every 2 weeks) on dollar spot severity, and the objective of the second trial was to evaluate the effect of three N sources (calcium nitrate, ammonium sulfate, and ammonium nitrate applied every 2 weeks) on dollar spot severity. Results from the N rate trial at both locations indicated that only the highest (29.3 kg N/ha) rate consistently reduced dollar spot severity relative to the nontreated control. Nitrogen source had minimal and inconsistent impacts on dollar spot severity based on location and year. Although these results show that meaningful reductions in dollar spot severity can be achieved by manipulating N fertilizer application rates, the rate of N needed for disease suppression may be impractical for most superintendents to apply and result in undesirable nontarget impacts.