We have Poa on our greens! I thought we were spraying to keep it out!
These are some of the statements I get from time to time. I will try to explain the issues with Poa on a golf course in the south.
We Superintendents have learned over the years that we actually have two Poa Annua seasons through the winter. The first starts around November and the second generally comes between January and March. The reasoning for this may be that this is generally when our pre-emergents start breaking down.
We sprayed our greens with a chemical called Tranxit last fall to take out any Poa and give us some preventitive action against it. You can see the results on the front approaches of a few greens (like #6) where our sprayer came off the green and the booms did not shut off until they were halfway done making the turn for the next pass. I would generally like to make a second application around February if conditions permit. You need to understand that the chemicals to remove the Poa is a herbicide, and that herbicides will harm our greens turf if the proper conditions are not present. The turf is most succeptable when it is just coming out of dormancy and the tender shoots are fairly new. An application under the wrong conditions could set back our greens for 2-6 weeks if the weather turned colder after application. In our area, our weather never stays cold enough, long enough to assure no damages to the turf. Spraying in the late fall is never a problem because the turf is established from a long growing season.
I am constantly looking for better chemicals to control our weeds. Our problem is that most of the best chemicals are priced out of sight and way out of our budget. but every year certain chemicals lose their patent's and the generic versions are released which then gives us more choices to choose from. Herbicides are the hardest chemicals to use on your greens. Slight mistakes can kill off areas in a heartbeat. Weather conditions can cause these chemicals to even more damage to their root systems. Timing is the key and we are faced with so many different variables it can be difficult to get applications out on time.