Achieving optimal poa annua seedhead control has proven to be a challenging task. I have witnessed situations where several courses have sprayed the same products / rates on the same days, yet their results varied greatly. There are many biotypes of poa annua, and they react differently to various growth regulators and rates.
Last season, one course experienced impressive results when compared to neighboring clubs. The following table illustrates the dates of application, GDD info (base 32 degrees) from the prior day, and products and rates applied at this course last spring. The application on May 2, 2013 was applied 5 days earlier than originally scheduled due to the observation of excessive growth. Likewise, the application on May 13, 2013 was sprayed 3 days ahead of schedule with a reduced rate of ArmorTech PGR 113 due to the presence of a DMI, ArmorTech TEB 360, in the mix. It’s also important to note that this green is roughly 90% poa annua.
Timing is critical. I recommend the website gddtracker.net to assist in timing your seed head treatments.
