Poa annua
a Control in
Cool Seasson Sports
Cool-Seas
Turf
uf
Bruce Branham and Matt Giese
University of Illinois a
and Syngenta Turf &
Landsscape
prob
blem?
the seed!
Prob
blem?
Despite the name, Poa annua in highly maintain
turf is mostly a perennia
al.
al
Seed production separa
ates Poa from other wee
problems.
Adapted to low heights of cut, compaction, and
shade.
Lack of environmental stress
s
tolerance
–Significantly more susceeptible to ice and freeze inj
–Shallow roots increase susceptibility
s
to heat and
drought
Why is Po
oa such a
probllem?
• Seed production
• Soil seed bank
–Seed production
•How
H
much
h seed
d
c a pure stand
can
t d off Poa
P
p
produce?
•Lush (1993) estimaated that a Poa annua
putting green could
d produce from 14 to 63
emperature – 200
01
01 (two locations
emperature – 200
01
01 (two locations
Why is Po
oa such a
probllem?
• Adapted
Ad
d to llow h
heights
i h off cut
• Produces
P d
abundan
b d ntt seed
d
• May
M b
begin
i as an annual
a
lb
butt over titime,
converts to a pere
p nnial.
• If onlyy an annual,, then
t
all yyou need is a
good preemergencce herbicide.
• With perennial Poaa, a postemergence
• Nature doesn’t like baare ground
• turf surfaces are pereennial
• Mechanical traffic, fooot traffic, divots, insects,
weeds and diseases all lead to voids
weeds,
• New plants establish from seed
• Existing plants spreadd vegetatively
New Athletic Field
• The delay (5-6 relattively Poa-free years); th
h
happy
titime!!
• Poa seed can comee in sod
sod, seed
seed, or traffic
from shoes, equipm
ment, etc.
• concentrated at the surface
• transient, seeds viable <6 years
• survivors bred betteer survivors
Poa control strategies
g
• Cultural
• Mechanical
• Biological
• Chemical
Cultural Practices
P
•
•
•
•
Returning
g clippings
pp g =
Poa overseeding
Fertility
Irrigation
Cultivation - Voids are
an invitation to Poa!
Poa Control Strategies
Biologica
al Control
o is a bacterium
at infects only Poa.
Not sufficiently
rulent for reliable
ontrol.
ontrol
Poa Control Strategies
Biologica
al Control
•Use naturally seleective pests
–Summer patch or the annual
bl
bluegrass
weevil specifically
ifi ll
attack Poa but not
n bentgrass
bentgrass.
•Disruptive; Pest ccontrols the timing
Poa Control Strategies
Mechanica
M h i all C
Control
t l
H d removall
Hand
–Still has place,
place particu
ularly on putting greens
greens.
•Cut out by hand or pplugging
•Effective on new fieelds with little Poa
Roundup dauber
Collecting clippings?
Poa Control Strategies
Chemica
al Control
• Preemergence
• Postemergence
g
• traumatic contrrol
• non
non-traumatic
traumatic ccontrol
• Fumigation
Poa Control Strategies
Chemica
al Control
eemergence
A forgotten strategy
y, but can be
mportant in athletic fields
Can enhance
C
h
poste
temergence progra
ut ineffective witho
out postemergence
artners.
Poa Control Strategies
Chemica
al Control
ostemergence
–controll off grassess ini grasses iis very
difficult
– Effective postemmergence herbicide
are necessary
y for long-term
g
Poa
annua control
Poa Control Strategies
Chemica
al Control
•Postemergence
P t
–Cultural
C lt l & enviironmental
t l ffactors
t
affect control
•i.e.
i e mowing he
eight temperature
eight,
rainfall, soil mo
oisture
-Development off herbicide
resistance is a concern!
c
Poa Control Strategies
Chemica
al Control
•Fumigation/Soil ssterilization
–Renovation onlly
–Reduces,
Reduces but d
does not eliminate,
eliminate
the soil seed ba
ank
–Can ggive a cleaan start,, but seed
is still present
–Expensive, longg-term
Preemerge
gence timing
g
• When to apply?
–In general, if you onlly make one application
apply in the
th late sum
mmer, somewhere
between August 1 an
nd September 10
10,
depending on locatio
on.
–If desired a second application
a
can be made
in the spring
spring, betwee
en April 1 and May 1
1.
Recommenda
ations for Poa
Control in Bluegrass
more safety
y
more effective
enefin,, dithiopyr,
py ,
rodiamine
enefin+trifluralin
endimethalin,
ensulide,
lid oxadiazon
di
bensulide
benefin
benefin+trifluralin
p
pendimethalin
dithiopyr
prodiamine
oxadiazon
Preemergen
nce Control
of Poa annua
Aug Aug Au
T t
Treatment
t
93
96
98
Control
4
21
27
Pre-M 60 WDG @ 3.0 lb ai/A
4
22
35
Ronstar 2G @ 3.0 lbs ai/A
a
7
24
31
Team 2 G @ 3.0 lbs ai/A
1
19
27
Betasan 4E @ 12 lbs ai/A
a
5
14
22
Preemergen
nce Control
of Poa annua
Aug Aug Au
Treatment
93
96
98
Control
4
21
27
Dimension 1 EC @ 0.5 lb
b ai/A
5
20
17
Barricade 65 DG @.65lb
bai/A
1
11
12
Balan 2.5 G @ 2.0 lbs ai/A
a
6
13
11
5
5
4
rograss 1.5 EC @ 0.75 lbs ai/A x 4
Preeme
ergence
Summ
mary
• I want to think thhis is an effective
strategy
gy in certain situations.
• However,, data shows
s
a little
different story
• Not a centerpiecce of Poa control
strategy; but ma
aybe helpful
f ll i a successful
following
f l postt
Postemerge
ence Contro
Traumatic versus non-traumatic control
–We’re talking trauma tot the field manager not
the grass!
g
The PGRs, paclobutrazo
ol and flurprimidol, are
chemical options for non
n-traumatic control.
These products graduallly reduce Poa annua
infestations when used regularly
r g
y during
g the
growing season.
PGRs forr Kentucky
Bluegrasss Athletic
Fie
elds
Poa encroachment into
K
KB
Treatment Rate,
Rate fl oz/A
% Poa Cover
--- 9 Oct 2006 --Control
24
TE @ 26
10
TE @ 26 fb PB @ 16
4
TE @ 44
6
PB @ 16
10
PB @ 16 fb 24
5
Effects of PB
B on Ball Lie
in
i a KBG
G Fairway
F i
- PGR
PGRs on Athletic
A
Turf
• PGRs increase turf deensity, which reduces
voids and openings in
n turf →less
less Poa
• Key is to have a moderate level of growth
regulation and stop applications right before
playing
l i season b
begin
ins.
Herbicide
es for Poa
Con
ntrol
• ethofumesate (Prograass™)
• bis
bis-pyribac
pyribac ethyl (Velo
ocity )
ocity™)
• mesotrione (Tenacity
(
yy™))
• amicarbazone (Xonerrate™)
• Available in springg 2012
Ethofum
mesate
• Current label
• “Fall applications to turfgrass sites to
control annual blueg
grass are most effective
if application is initia
ated during the period of
maximum weed gerrmination and ended as
close
c
ose to tthe
e first
st killing
g freeze
ee e as poss
possible.
be
Spring applications may be made during
the period of maxim
mum weed germination
germination.”
Ethofumessate : KBG
• Very cultivar dependennt
• Tolerant cultivars
• Moonlight,
M
li ht A
America,
i
S
SR2109 and
SR2109,
d Ab
Absolute
l t
• Sensitive cultivars
• Northstar,
Northstar Total Eclip
pse
• Example program
• Initiate 1-Aug,g 1.5 fl oz/M,
o
7-d int., 4 apps
• Better success with twwo apps @ 3-4 fl oz/M,
Ethofumessate Notes
• Marginal control
• Safety an issue on KBBG but very safe on
PRG
• Not enough safety & efficacy to warrant use
Bis-pyriba
py ac Sodium
• Injurious to KBG
KBG, safe
e on PRG
• Good control,
control but will severely injure most KB
cultivars and kill some
e KBG cultivars
• Might be useful on ouut-of-play areas where y
can wait for the turf to
o recover
recover.
• Application rates
• 100 gms
g sa
ai/A
/ ((2 o
oz prod/A)
od/ ) weekly
ee y for
o 6 wee
ee
• 30 gms ai/A (6 oz prod/A) two apps on 10-1
Mesotrion
ne for Poa
Control in Kentucky
Blueg
Bl
grass
Tena
acity
AKA mes
sotrione
• A bleaching herbiccide,
cide susceptible plant
turn white - can be
e jarring.
• Safe when appliedd at the time of seedin
Kentucky
K
t k bluegras
bl
ss - provides
id b
better
tt we
control than Siduro
on.
• Use rates
ates 5
5-8
8o
oz/A
/A ( 0.16-0.25
0 6 0 5 lbs
bs a
ai/A)
/ )
a seasonal maximum of 16 oz/A (0.5 lbs
ai/A)
i/A)
Tenacityy Results
Trea
atments Initiated on:
nacityy Total
7/2
24/0
5/6/09
5/3/10 6/7/10 7/5/1
t (oz/A) apps
9
---------%
%P
Poa annua Control
Control--------MWF
10
86
9
93
40
97
92
, MTh
10
85
7
78
75
100
92
, MTh
5
80
9
97
0
76
90
2, M
5
57
4
41
15
43
92
Notes on Mesotrione
M
• Low rates, frequennt applications work
best, kinda like an IV for the turf!
• The hotter the temmperatures, the better
th h
the
herbicidal
bi id l activ
tivity
it
• Under hotter conditions,
itions need less apps
to g
get control
2011 Ressearch on
mesottrione
•
•
•
Spray
p y volume
Adjuvants
j
Nitrogen
g fertility
y
40 GPA
G
20 GPA
Fertillityy on
meso
otrione
•
•
•
Adjuvan
nts with
mesottrione
Adjuvant trials done
g warm weather
during
gave excellent control
g
of adjuvant.
j
regardless
Stick with NIS at
0.25% v/v for now
Adding 2.5% v/v UAN
g
y increased
significantly
control.
Recomme
endations
Apply 1
1.5
5 lbs N/M ass urea at initial applica
or within 7 days
y of sttarting.
g
Spray volume of 20 GPA
G
Use a non-ionic surfa
actant (NIS) at 0.25 %
and UAN (28 % N) at
a 2.5 % v/v
Apply 3.2 oz prod/A 5 times 2x/week.
For maximum Poa control, apply 1.6 oz
prod/A 10 times 3x/w
week (should not be
necessary).
Notes
on
M
Mesotrione
• Remember,
Remember death on bentgrass!
• Works best with hiigh temperatures
• Once bleached,
bleached high temperatures lea
to rapid kill
• Fall applications can also be effective,
even though much
h cooler
• Mesotrione is rapidly metabolized by
plants
Potentia
al Game
Chan
nger
• Amicarbazone (Xoonerate
onerate™)) - new
herbicide develope
ed by Arysta
LifeSciences
• to receive EPA labbel in the first quarter
of 2012
• PS II inhibitor that controls Poa with
marginal safety on Kentucky bluegrass.
• PS II inhibitors havve been shown to
4 + 0.50 oz/A X2
Tenacity plus Ami
4 + 0.25 oz/A
o
X2
Tenacity plus Ami
Amicarb
bazone
Just started testing
this combination this
fall
Messotrione + Amicarbazo
4 + 0.5
0 5 oz prod/A 2 app
Better safety, fewer
applications lower use
applications,
rates
This will be our focus
in 2012
2012.
Poa contro
ol in Sports
Turf
urf
Mesotrione has best
safety combined with high
levels of control
Mesotrione +
amicarbazone appears to
be superior - more work
needed
Questions with PRG
safety
Thankk you!
y
•
Questions?