10/23/2023 - By Dr. Jeff Atkinson

Study:                   Annual Bluegrass (Poa annua) Control Using Fertilizer with StayGuard 0.125% in bermudagrass

Location:             Lake Buena Vista, FL

Investigator:      Dr. Patrick McCullough

Summary:           A field trial was conducted by Dr. Patrick McCullough of the University of Georgia to investigate the efficacy of fertilizer with StayGuard 0.125% alone or in combination with Princep and Tribute Total, for preemergence (PRE) and PRE + postemergence (POST) annual bluegrass control. Standalone PRE treatments were applied to a stand of actively growing bermudagrass on 14 October 2022, and PRE + POST treatments were applied on 17 November 2022. Plots were maintained at a 0.5” mowing height and soil in the trial area was sandy with ~1% organic matter. All treatments, including the nontreated, received the same fertility inputs throughout the trial. Annual bluegrass percent cover in the nontreated plots averaged 38% on 17 April 2023, where Fertilizer with StayGuard 0.125% applied at 300 lbs/A on a 15-0-15 POLYON® controlled-release fertilizer blend provided 44% control on 17 April 2023. Fertilizer with StayGuard 0.125% applied at 200 lbs/A on a 22-0-22 POLYON® fertilizer blend followed immediately by a spray application of Princep at 1 qt/A, plus Tribute Total at 1 oz/A, provided 92% control on 17 April 2023. This data suggests Fertilizer with StayGuard 0.125% is an effective tool when incorporated into a PRE + POST annual bluegrass management program.

Figure 1. Annual bluegrass control following a PRE application of StayGuard 0.125% on Fertilizer on 14 October 2022 or a PRE + POST application of StayGuard 0.125% on Fertilizer followed immediately by a spray application of Princep and Tribute Total. Different letters between treatments within a rating date indicate a statistically significant difference at the α=0.05 level. Lake Buena Vista, FL.

Figure 2. The trial area on February 2^nd, 2023. Poa annua pressure can be observed in nontreated plots.

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