SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/162108
FieldScience | By James T. Brosnan and Gregory K. Breeden University of Tennessee Herbicide Resistance: A Problem on the Horizon for Athletic Field Managers? A DORMANT bermudagrass athletic field A lthough certification programs are in place to limit the presence of weeds in turfgrass seed and vegetative material (i.e., sod, sprigs, etc.), infestations are common on warmand cool-season athletic fields. Weeds such as crabgrass (Digitaria spp.), goosegrass (Eleusine indica) and annual bluegrass (Poa annua) can be found on fields at all levels of play. Controlling these species is important to athletic field managers in that weed infestations can reduce both field quality and safety. Implementing sound agronomic practices and integrated pest management strategies can help discourage the presence of weeds on athletic fields. However, in many cases herbicide applications are often required for complete eradication. HERBICIDE RESISTANCE IS A PROBLEM Herbicide resistance has been defined as the inherited ability of a plant to survive and reproduce following exposure to a dose of herbicide 8 SportsTurf | September 2013 normally lethal to the wild type (Vencill et al. 2012). The onset of herbicide resistant weed biotypes is a global problem of agriculture, turf included. Nearly 400 biotypes of herbicide resistant weeds have been reported worldwide, spanning over 200 different plant species (Heap 2013). The rate at which herbicide resistant weeds have developed in agricultural production has increased following the adoption of herbicide-tolerant crops (i.e., Roundup Ready). This technology allowed for herbicides targeting a single site of action (i.e., herbicides that work in a similar manner) to be repeatedly used for effective weed control; thus, reducing the diversity of techniques used for weed management (Vencill et al. 2012). As a result, selection pressure for herbicide resistant weed biotypes increased. Despite the fact that herbicide resistance in crop production has been an issue since 1970, several reports of herbicide-resistant turfgrass weeds have surfaced in recent years, illustrating that herbicide resistance is an emerging problem of turfgrass weed management requiring intervention. While most of these cases of her- GLYPHOSATE resistant annual bluegrass (Poa annua) in dormant bermudagrass. bicide resistance have occurred on golf courses, it is imperative that athletic field managers A) become aware of this emerging issue and B) make changes to their programs to prevent herbicide resistance from becoming widespread on athletic fields in the near future. WHAT CAUSED THE PROBLEM? While herbicide tolerance traits (i.e., Roundup Ready) are not used in the turfgrass industry, diversity of weed management techniques is often lacking. Turfgrass managers often repeatedly apply the same herbicides for control of problematic weeds year-after-year. This has led to the development of herbicide resistant biotypes of annual bluegrass (Poa annua), goosegrass (Eleusine indica), and smooth crabgrass (Digitaria ischaemum) in turfgrass. GLYPHOSATE RESISTANCE Bermudagrass (Cynodon spp.) athletic fields www.sportsturfonline.com