Creeping bentgrass is used extensively on golf course fairways throughout the northern United States. It is typical for variety trials all throughout the country to use management practices where all diseases are controlled for comparison.
Currently, there is limited available research in cultivar testing for reduced fungicide input programs. Today, many golf course superintendents are looking to cut costs and reduce inputs to their largest acreages of highly managed turf, the fairways.
The objective of this work was to determine the susceptibility and performance of creeping bentgrass cultivars under a reduced fungicide input management program for dollar spot disease on fairways.
Twenty-four different cultivars of creeping bentgrass and one colonial bentgrass cultivar were selected for the study. Plots were established in October of 2008. Each plot is split in half with one half receiving fungicide applications and the other side receiving no fungicide. Fungicide applications of Daconil Ultrex at 3.2 oz. with Emerald at 0.18 oz are applied when a 5% percent threshold of dollar spot occurs on the cultivar ‘Declaration’.
The August 23 sampling date for the split plots shows that acceptable levels of visual quality are achievable when limiting fungicide applications. Best visually rated varieties under this reduced management include, Kingpin, Pennlinks II, SR1150, CY-2, Declaration, Shark, OO7 and Memorial. Cultivars rated at or below acceptable visual quality include T-1, Southshore, Imperial, Penn A4, Crystal Bluelinks, Bengal, Independence and Century. Meanwhile, all split plots left untreated produced unacceptable levels of turfgrass visual quality. These untreated plots had dollar spot levels up to 60-80% blighted turfgrass in some cases.