Preemergence herbicide effects on St. Augustinegrass establishment

Abstract

St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is one of the most common turfgrass lawn species of warm-season climates. Like many turfgrasses, it is produced as sod. Weed control during sod production is problematic, due in part to intolerance of St. Augustinegrass to a range of useful turfgrass herbicides, and because the open canopy and growth-conducive conditions of sod production favor certain difficult-to-control weeds. Although those weeds are best preventatively controlled using preemergence herbicides, many preemergence herbicides also adversely affect vegetative propagation of turfgrasses. Field research was conducted at the Mississippi State University, near Starkville, Mississippi, USA, to evaluate the effects of dithiopyr, pendimethalin, prodiamine, liquid-and granular-applied oxadiazon, atrazine, S-metolachlor, atrazine + S-metolachlor, and indaziflam on St.Augustinegrass establishment from plugs. Plots (2.25 m 2 ) were planted with 10 plugs (225 cm 2 apiece), and preemergence herbicides were applied at standard use rates 1 day after planting. Visual estimates of percentage cover were collected weekly, and aerial imagery was collected weekly to biweekly. Visual cover and vegetation index data were regressed to estimate days to reach 50% maximum nontreated response. Liquid-applied oxadiazon and atrazine were the only treatments that did not increase days to reach 50% cover in both replication years. Dithiopyr, prodiamine, S-metolachlor, and indaziflam increased days to reach 50% cover in both replication years. The normalized difference vegetation index, ratio vegetation index, and chlorophyll index-red edge derived from an aerial sensor, detected similar, but fewer, treatment differences compared to estimated visual cover. INTRODUCTIONSt. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is a commonly grown lawn grass in the southeastern Abbreviations: CIRE, chlorophyll index-red edge; NDVI, normalized difference vegetation index; RVI, ratio vegetation index.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Assessing unmanned aerial vehicle‐based imagery for breeding applications in St. Augustinegrass under drought and non‐drought conditions

“…The objectives of this study were to (i) compare measurements of PGC and NDVI between ground-and UAV-based platforms under drought and non-drought conditions in a St. Augustinegrass population segregating for drought response and morphology, (ii) identify VIs that are significantly correlated with PGC, (iii) determine relationship between VIs and H 2 for both ground-and UAV-based measurements for use in breeding and selection, and (iv) characterize and compare VIs for St. Augustinegrass selection under drought versus non-drought conditions. Caturegli et al, 2016;Wang et al, 2021Wang et al, , 2022Wilber et al, 2022Wilber et al, , 2023Yousfi et al, 2022;Zhang et al, 2019Zhang et al, , 2023 Normalized green red difference index Note: Some equations were developed using precise near infrared (NIR) or red edge (RE) wavelengths rather than the bandwidths used in this study that the Micasense Altum sensor measures.…”