Wednesday, May 18, 2011

Poa annua Control & Velocity Herbicide

 This week we have begun a series of applications of Velocity Herbicide to reduce the Poa annua population in our fairways.  This will be the third round of Velocity since seeding the fairways in 2008.  The first application occurred in 2008 with another round in 2009.  In 2010 we used a different product called "Trimmit" to suppress Poa growth.

This year we are using a different strategy to attack the Poa.  In the past we applied Velocity in 6 applications spaced one week apart.  This strategy quickly killed the Poa but left us with voids of dead Poa annua in the fairway.  Our plan for 2011 is to use the same quantity of Velocity but to space the applications over the entire season with each application being spaced approximately one month apart.  The idea is to have a "slow conversion"- for the Poa to have a long slow death during which time the bentgrass has a significant competitive advantage.

You may notice some yellowing of the fairways in the days following Velocity applications.  This condition lets us know the product is working and the bentgrass will recover within 7 to 10 days.  We are also applying fertilizer containing iron to help mask the yellowing effects.

You may be wondering why the Poa keeps coming back?  Poa reproduces from seed and Wakonda has 90 years worth of Poa seed throughout the property- billions of tiny seeds which produce new plants when the opportunity arrives.

We are not solely dependent on chemicals to control Poa.  We do everything we can in our maintenance strategies to promote the bentgrass and antagonize Poa.    On greens and collars we cut the Poa plants out by hand.  The game of golf generally promotes Poa growth: divots, low mowing heights, and cart traffic all promote Poa.

We fit our sprayer with a small piece of plywood so we could spray a full rate of Velocity Herbicide right up to the edge of the fairway.