Field Science
14 SportsTurf | March 2015 www.sportsturfonline.com
The very low mowing height and intense
management regimes used on golf
courses provide an ecological advantage
to Poa annua and it easily outcompetes
other preferred grass species.
This weed could always be found in
sports turf areas, but the less-extreme
management conditions that predomi-
nated on most sports turf through the
1900's meant that Poa annua was usu-
ally not a major problem in athletic
fields in most climatic zones. This has
changed in the 2000's, and the greater
intensity with which modern fields
are managed is resulting in Poa annua
becoming a common complaint among
sports turf managers. Figure 1 is from
the Burlington Bees baseball field in
Burlington, IA. The Burlington field sits
in a low area along the Mississippi River
and is surrounded by trees and a fence
that results in a microclimate that is very
conducive to Poa annua infestation. Add
to that the high level of maintenance ini-
tiated by Certified Sports Field Manager
T.J. Brewer, and Poa has become an
increasing problem in recent years.
Once it gets a foothold in cool-wet
weather, Poa does what it does best in
stress periods; it simply dies. Figure
2 is from a sports field at Iowa State
University. The clear outline of the Poa
annua can be seen as lighter colored
patches in the darker colored Kentucky
bluegrass (Poa pratensis). So, now that it
is here, how do you kill it?
Controlling Poa
annua in sports turf
■ By Dr. Nick christiaNs
M
uch of my career has been spent on trying to kill annual
bluegrass, better known asPoa annua in golf course turf.
While it does occur in other turf areas, such as lawns, it
has always been on the golf course where this species has
presented the biggest problem.
Fig.1. Poa annua is becoming more common in sports fields each year as management levels of these areas intensifies. Courtesy of T.J. Brewer,
CSFM, Burlington Bees, Burlington, IA.
Fig.2. Poa annua in a sports field at Iowa
State University. Courtesy of Tim Van Loo,
CSFM, Iowa State.
