Too late for Poa annua control? Ummmm…actually, it’s perfect timing!

Recent research and practical experience is clearly showing that mid-to-late fall is the most effective time to control Poa annua in warm-season turf. Not only can highly effective control be expected, herbicide mixes used at this time go a long way in decreasing the potential development of herbicide resistant populations.

• Why wait? Specticle^® FLO applied in early fall has been exceptionally effective for many years, but waiting until after Poa annua germination to apply a PREPOST tank-mix provide greater benefits including:
  • Wider window of application since annual bluegrass germination can vary from year to year
  • More flexibility with reduced labor forces
  • Improved control of later germinating winter annuals like henbit, chickweed, etc.
  • More flexibility due to variable fall/winter weather including:
    • Heavy rainfalls from tropical storms that could leach and degrade herbicides
    • Warm temperatures that could encourage annual bluegrass germination throughout the winter
    • Severe cold that could exaggerate winterkill, thus affecting use of most PRE herbicides
  • University research has shown that tank-mixing herbicides with different sites (modes) of action is more effective than rotating herbicides with different sites of action when weed resistance management is being considered
• Highly effective Fall option – Envu’s PRE3 is a tank-mix of three herbicides (Specticle FLO + Tribute^® Total + simazine)
  • Designed to deliver consistent annual bluegrass control and reduce the likelihood of developing resistance
  • Features the most effective preemergence Poa annua herbicide (Specticle) combined with one of the most effective POST herbicides on all stages of Poa annua (Tribute Total) plus simazine for an additional mode of action for fighting resistance
  • PRE3 applications are designed to be applied later than the traditional PRE-only applications in late summer
    • Single or split applications of PRE3 can be made starting in late-October or November based on your location, weather, amount of annual bluegrass germination, etc.
    • Rates, timings, and application intervals can also be based on weather and previous experience
  • PRE3 also controls problematic winter annual broadleaves and annual sedges 
• Other options:
  • Resistance is becoming a significant issue with Poa annua, so alternating and/or tank-mixing multiple modes of action is critical. Some of our favorites are:
    • Glyphosate could be rotated in the tank-mix for nonselective control on dormant fairways for another herbicide site of action. Additionally, university research and practical experience shows that 5 oz/A of RoundUp (4 lb ai/gal formulations) provides excellent Poa annua control and exceptional turf safety, even on green bermudagrass
    • Glufosinate could also be rotated in the tank-mix for still another nonselective site of action on dormant fairways where glyphosate resistance is a concern
• More information – always refer to the label for specific recommendations and contact your Envu area sales manager if you need assistance.