SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: http://read.dmtmag.com/i/318924
www.stma.org June 2014 | SportsTurf 25
Field Science | Q&A with Ken Hutto Q&A with Dean Mosdell, PhD
F
or an overview of post-emergence weed control,
including herbicide selection and overall appli-
cation strategies SportsTurf recently sought the
insights of Dean Mosdell, PhD, field technical
manager — west, at Syngenta Lawn & Garden.
SportsTurf: Have there been noticeable changes in post-
emergent control results since MSMA was banned?
Mosdell: Weed control strategies have changed slightly. MSMA
provided an inexpensive solution for many monocot weeds.
Strategies may have greater emphasis on making pre-emergence
more effective, such as timing or split/multiple applications. There
are several post-emergence herbicides available for warm and cool-
season turf, but are narrow in spectrum and/or safety on various
turf species. The biggest gap in weed control without MSMA is
dallisgrass control in cool-season turf.
SportsTurf: Please share your general post-emergent herbi-
cide strategies for cool-season and warm-season athletic turf.
Mosdell: Selection is based on weeds present and turf type.
Any strategy would need to consider turf type, weed targets and
best timing for weed control that works into the use schedule
and maintenance program of the athletic field.
SportsTurf: In general, what is the best strategy for post-
emergence weed control?
Mosdell: Again, strategy would be based on weeds present
and turf type. Dicot weeds can be controlled with pre-mixes
of growth-regulating-type herbicides such as 2,4-D, dicamba,
triclopyr, MCPA and others. There are numerous mixes that
vary in ratios and components of these herbicides to improve
the safety on certain turf types. There are fewer options to con-
trol grass weeds post-emergence. The most common summer
annual grass is crabgrass. Options for control include products
that contain quinclorac, or Tenacity and Acclaim herbicides.
On warm-season turf, other options include ALS-inhibiting
herbicides such as Monument or pre-mixes of several of these
ALS herbicides. Older triazine chemistry is still used on warm-
season turfgrasses. It's important to read the label for safety on
turf species as they vary widely and mixtures may further reduce
labeled turf species.
SportsTurf: Are there different products and/or strategies
for post-emergence control of grassy weeds and broadleaf
weeds?
Mosdell: Yes, with few exceptions most post-emergence her-
bicides are effective on either dicots or monocot weed species.
Tenacity herbicide, with pre- and post-emergence activity, will
control crabgrass as well as dandelion, oxalis and speedwells.
In the herbicide screening process it is difficult to select for a
broad spectrum grass herbicide to control a grass weed in turf-
grasses since their physiology is similar. An effective strategy is
to use a pre-emergence herbicide and treat any escapes of grass
weeds with a post-emergence. There are man y effective post-
emergence herbicides to control dicot weeds. Best strategy is to
maintain a healthy turf stand and control any dicot weeds that
pop-up with a broadleaf herbicide. There are many to choose
from depending on weed species and turf type.
SportsTurf: Are there any new post-emergent herbicides
near market that you can discuss?
Mosdell: I think in the near term there will be mixtures of
post-emergence herbicides, similar to the broadleaf herbicide
products, to improve spectrum, efficacy and turf safety. With
the loss of MSMA in several markets, opportunities exist for new
post-emergence grass herbicides. ■
Dean Mosdell, Ph.D. is field technical manager