Cross and multiple herbicide resistance in annual bluegrass (Poa annua) populations from eastern Texas golf courses

Abstract

BACKGROUND Annual bluegrass is a troublesome weed in managed turf systems. A survey was conducted to evaluate the prevalence of herbicide resistance in golf course populations of annual bluegrass in eastern Texas. Screenings were conducted for two photosystem II (PS II)‐inhibitor herbicides [simazine preemergence (PRE), amicarbazone postemergence (POST)], two acetolactate synthase (ALS) inhibitors (foramsulfuron POST, trifloxysulfuron POST) and one microtubule assembly inhibitor (pronamide PRE/POST). RESULTS Ninety percent of the populations were found to be resistant to at least one of the tested herbicides. The TX15‐14 population was >490‐, 178‐, 10‐, 26‐, 4.3‐ and 3.8‐fold, and the TX15‐27 population was >490‐, 16‐, 28‐, 84‐, 5.2‐ and 4.1‐fold less sensitive to simazine, amicarbazone, foramsulfuron, trifloxysulfuron, pronamide POST and pronamide PRE, respectively, compared to the susceptible standard TX15‐SUS. Populations resistant to pronamide POST were completely controlled by pronamide PRE at the label recommended rate. The ALS and psbA gene sequence analysis indicated the presence of target site mutations (Ser‐264‐Gly in the psbA gene of TX15‐14 and Trp‐574‐Leu in the ALS gene of TX15‐27). However, given the absence of any target‐site mutation in the ALS gene of TX15‐14, the psbA gene of TX15‐27 and α‐tubulin of both populations, nontarget site mechanisms of resistance are suspected. CONCLUSION This is the first case of multiple herbicide resistance in annual bluegrass populations to three herbicide modes of action. Results show the widespread occurrence of multiple herbicide resistance in golf course annual bluegrass populations in eastern Texas and emphasize the need for the development and implementation of effective resistance management practices. © 2020 Society of Chemical Industry

Wood vinegar for control of broadleaf weeds in dormant turfgrass

“…Numerous weed populations have now evolved resistance to multiple herbicide MOAs (Brosnan et al 2020a(Brosnan et al , 2020bDuke et al 2019;Heap 2021;McCullough et al 2016McCullough et al , 2017Yu et al 2017). At present, herbicide-resistant weed populations, especially annual bluegrass, are prevalent in turfgrass (Brosnan et al 2020a(Brosnan et al , 2020bMcCullough et al 2016McCullough et al , 2017Singh et al 2021). An additional study is needed to determine the application rates and regimes of using wood vinegar for control of glyphosate-resistant annual bluegrass in dormant turfgrass.…”

“…and zoysiagrass, glyphosate is the most commonly used nonselective herbicide for weed control (Johnson and Riordan 1999;Toler et al 2007). However, glyphosate-resistant weeds, especially annual bluegrass (Poa annua L.), are frequently reported in managed turfgrass systems (Binkholder et al 2011;Brosnan et al 2012;Heap 2021;Singh et al 2021). In Australia, an annual bluegrass population has evolved multiple-resistance to bispyribac-sodium, rimsulfuron, simazine, glyphosate, pronamide, and endothall (Heap 2021).…”

“…In Australia, an annual bluegrass population has evolved multiple-resistance to bispyribac-sodium, rimsulfuron, simazine, glyphosate, pronamide, and endothall (Heap 2021). The prevalence of multiple herbicide resistance can significantly reduce the herbicide options available for weed control and pose serious challenges to sustainable turfgrass management (Singh et al 2021). Brosnan et al (2020a) suggested that continued reliance on glyphosate to control annual bluegrass in dormant turfgrass may increase selection pressure for glyphosate resistance on other winter weed species, especially broadleaves, which are the dominant weed spectrum apart from annual bluegrass.…”

Developing and implementing a sustainable, integrated weed management program for herbicide‐resistant Poa annua in turfgrass

“…There are 49 herbicide resistant P. annua cases reported worldwide and there are 18 cases reported in the United States (Heap, 2023). Cases are likely severely under‐reported based upon ongoing research (Ignes et al., 2023; Rutland et al., unpublished data, 2023; Singh et al., 2021). The worrying trend is that for some turfgrass scenarios, there are no longer effective means of chemical control (Allen et al., 2022).…”

“…Target site resistance in P. annua in the United States is reported to acetolactate synthase (ALS) Inhibitors (Group 2) (Brosnan et al., 2015, 2016; Cross et al., 2013; McElroy et al., 2013; Rutland et al., unpublished data, 2023), microtubule assembly inhibitors (Group 3) Ignes et al., 2023; Rutland et al., 2022; Rutland et al., unpublished data, 2023), photosystem II (PSII) inhibitors (Group 5) (Kelly et al., 1999; Perry et al., 2012; Rutland et al., unpublished data, 2023), and enolpyruvyl shikimate‐3‐phosphate (EPSP) synthase inhibitors (Group 9) (Rutland et al., unpublished data, 2023). In some cases, the P. annua is resistant to more than one SOA (Brosnan et al., 2015; Ignes et al., 2023; Singh et al., 2021).…”