Poa Annua on Greens

 We all remember last year greens #1,2,9,18 and the putting green had something different growing on it that we had not experienced before. The type of weed is called Poa Annua and/or Annual Bluegrass, it occurs during cool season months only and in the south it is considered a weed. Where as in other parts of the country many golf course greens are a Poa Annua/Bluegrass variety, Many of the courses along the Pacific Coast are Poa Annua greens.
 Willow Fork had not seen this type of weed on the greens before-- although it has been around for sometime out in the roughs where a pre-emerge control was not applied. The reason the greens in the past were always clean of this type of weed was due to a pre-emerge product called Rubigan. Cost of this application ranged in the $4000.00 area.
 When the new varieties of turf for the greens came out in the late 1990 to early 2000's, overseeding greens was not necessary. This type of turf can withstand colder temperatures at a much higher level than the original turf variety type could handle. Therefore, Superintendents were no longer spraying the pre emerge product (Rubigan) because of the cost and simply spraying a herbicide at a relatively low cost on the putting surfaces. This was awesome!
 Now that 5 to 10 years have gone by removing Poa Annua isn't happening by using the same 1 or 2 of the herbicides available to remove any existing Poa Annua. In 2014 6 herbicide application were made to our greens and ZERO kill took place. So in 2015 changes have to be made in order to keep this weed under control.
 The types of herbicides that have been used in the last 7 years are a contact herbicide. We simply spray it on the greens and leaf blade would intake the herbicide and kill the plant-no more. This generation of plants have now become resistant to these herbicides and last year proves the case. In 2015, a new plan was being brewed up to control Poa Annua. One of the two herbicides we actually started applying back in August and continued spraying an application every 30 days along with a growth regulator before the plant ever sprouted, hoping for better control. Everything was looking promising till the week of Christmas and that's when we found the Poa Annua scattered all over #1 green, and get this, the putting green is clean this year-remember last year, it was bad.


SO NOW WHAT???


There is a herbicide out there with a completely different active ingredient however there is some risk in damaging the turf to the greens if sprayed at full rates and/or overlapping occurs. We will be spraying at half rates and repeating in 30 days. This herbicide is required to be watered in, it's purely a soil activated driven herbicide. By watering it in, the herbicide will move into the soil and the roots will intake the herbicide for the kill. By having a different active ingredient we have now changed to a different family in the herbicide group. This Poa Annua has never been in contact with this type of active ingredient. Once it has been watered in, it will need to dry before play is allowed to walk on it, mainly because this product is easy to move by footsteps, mowers, rainfall. We want this product to completely dry onto the soil and then go to work and kill the DAMN POA ANNUA!!!!


Willy Plowman
Golf Course Superintendent