1. Herbicide resistance in SA
Dr Peter Boutsalis,
Christopher Preston & Gurjeet Gill.
School of Agriculture, Food and Wine
University of Adelaide
Plant Science
Consulting
7. Ryegrass resistance in Mid-North SA
Northern SA
Results of random weed surveys conducted by the University of Adelaide. Paddocks were scored as resistant if
the seeds collected exhibited >20% survival in a pot test conducted the following winter. Thus samples that
exhibited 1% to less than 20% survival were scored as non-resistant.
8. Ryegrass resistance in SA Mallee & SE
Resistance defined where ≥ 20% survival in a pot test
9. Ryegrass resistance in Eyre Peninsula- 2009
Resistance defined where ≥ 20% survival in a pot test
11. Ryegrass resistance- Group A’s
FOPS DEN DIM
If resistant
to below:
Hoegrass Verdict Targa Axial Achieve Select Factor
Hoegrass - R R ? ? ?
?
Verdict R - R
? ? ? ?
Targa R R -
? ? ? ?
Axial R R R - R
? ?
Achieve R R R R -
? ?
Select R R R R R -
?
Factor R R R R R R -
Rate response: Select, Factor, Select + Factor
12. Ryegrass resistance- Group B’s
Sulfonylureas IMI’s TP’s
If resistant to
below:
Logran Glean
Hussar
(ryegrass)
Atlantis
(wild oats)
Intervix/
OnDuty
Crusader
Logran - R ? ? ? ?
Glean R - ? ? ? ?
Hussar R R - R ? R
Atlantis R R R - ? R
Intervix R R R ? R ? - R ?
Crusader R R R R ? -
13. Life Impact The University of Adelaide
Two main species
of Brome
• B. diandrus (Great Brome)
– medium rainfall
regions
– generally earlier
germination
• B. rigidus (Rigid Brome)
– lower rainfall regions
– late and staggered
germination
Herbicide resistance in Brome
14. Life Impact The University of Adelaide
Brome Herbicide resistance- random
surveys
Survey Year Verdict
(%)
Select
(%)
Atlantis
(%)
Crusader
(%)
Intervix
(%)
South Australia
Mallee 2012 0 0 51 59 0
Mallee 2007 0 0 33 - -
South East 2012 14 0 16 14 0
Mid North 2013 0 0 40 - -
Mid North 2008 2 0 3 - 0
Eyre Peninsula 2009 0 0 5 - -
Victoria
Western 2010 6 7 37 - -
Northern 2011 0 0 0 - 0
Atlantis resistant brome also resistant to Crusader and Monza
15. Life Impact The University of Adelaide
Why Brome is a problem?
• Widely distributed
• Distribution increasing in no-till cropping
• Wide germination window
• Limited herbicide choice in-crop
– Wheat: Group B herbicides
– Broadleaf crops: Group A herbicides
• Herbicide resistance is developing
16. Life Impact The University of Adelaide
Multiple germinations
• Knockdown, pre-emergent, post-emergent
(dead plants), second post-m required.
17. Life Impact The University of Adelaide
Group A Resistance- Verdict
18. Life Impact The University of Adelaide
Group B IMI Resistance
(1800ml/ha Intervix)
19. Life Impact The University of Adelaide
Glyphosate resistance-
Maitland SA & Ouyen Vic.
Increasing rate improves control
Target site overexpression- eg. GLY resistance in brome
20. Brome resistance- Group A’s
FOPS DIM
If resistant to
below:
Verdict Targa Select Factor
Verdict - R R ? R ?
Targa R - R ? R ?
Select R ? R ? - R ?
Factor R ? R ? R -
21. Brome resistance- Group B’s
Sulfonylureas IMI’s TP’s
If resistant to
below:
Monza Atlantis
Intervix/
OnDuty
Crusader
Monza - R?
?
R?
Atlantis R - ? R?
Intervix R R - R
Crusader R R ? -
22. Life Impact The University of Adelaide
Weed Control- in crop
• Knock-down (non-selective)- delayed
emergence!
• Pre-emergent herbicide mixes
– Trifluralin, Metribuzin, Sakura etc.
• Post-emergent herbicides
– Group A: Targa, Verdict, Select- dicot crops
– Group B: Atlantis, Crusader, Monza- wheat
– Group B: Intervix, Midas- Clearfield w/b/c
• Limited choice of different MoA herbicides
• Increased reliance on herbicides -> resistance
23. Life Impact The University of Adelaide
Brome grass control at Pira, Vic 2013
Untreated control
Sakura + Avadex Xtra
Source: M Witney (DM)
24. Life Impact The University of Adelaide
Efficacy of pre-em herbicides and brome seed germination
Slide 24
Trif750
Trif1500
Trif3000
Bromus diandrus
T-0
T-3
T-5
T-7
T-10
T-12
T-14
a
60g/ha
Sakura
120g/ha
Sakura
240g/ha
Bromus diandrus
T-0
T-3
T-5
T-7
T-10
T-12
T-14
n
75g/ha
M
etribuzin
150g/ha
M
etribuzin
300g/ha
Bromus diandrus
T-0
T-3
T-5
T-7
T-10
T-12
T-14
Trif750
Trif1500
Trif3000
0
20
40
60
80
100
Herbicidedamage(%)
Bromus diandrus
T-0
T-3
T-5
T-7
T-10
T-12
T-14
Sakura
60g/ha
Sakura
120g/ha
Sakura
240g/ha
0
20
40
60
80
100
Herbicidedamage(%)
Bromus diandrus
T-0
T-3
T-5
T-7
T-10
T-12
T-14
M
etribuzin
75g/ha
M
etribuzin
150g/ha
M
etribuzin
300g/ha
0
20
40
60
80
100
Herbicidedamage(%)
Bromus diandrus
T-0
T-3
T-5
T-7
T-10
T-12
T-14
b
d
f
Trifluralin
Sakura
Metribuzin
25. Life Impact The University of Adelaide
Glyphosate Resistance
Christopher Preston, Jenna Malone and Peter
Boutsalis
School of Agriculture, Food & Wine, University
of Adelaide
30. Results using Seed Testing
Herbicide
Product
Rate
Herbicide
Group
Farmer
paddock
(g or ml/ha)
Surviva
l
(%)
Rating
Verdict + 1% Hasten 85 A-FOP 70 RR
Select + 1% Hasten 250 A-DIM 20 R
Select + 1% Hasten 500 A-DIM 0 S
Hussar + 1% Hasten 200 B-SU 90 RRR
Atrazine + 0.2% BS1000 2000 C 0 S
Triflur X 1000 D 0 S
What’s the outcome if farmer had chosen Verdict?
32. Herbicide tactics at different stages to
control weeds
Rotate between different modes of action
Trifluralin, Avadex, Boxer Gold, Sakura,
Propyzamide
In-crop (Group A & B’s) resistance. Opportunities
exist- use Herbicide Resistance Testing
Seed-set: Crop topping- canola, pulses, wheat
33. NEW HERBICIDES
Adelaide University is investigating:
New MoA herbicides selective in wheat & canola
New non-selective knockdown herbicide
34. IWM Crop Competition tactics that
help herbicides work better!
• Crop competition- barley-oats-trit-wheat-durum
• Crop choice- cereals vs broadleaf crops
• Seeding rate/ Crop density
• Row Spacing
• Cultivar choice
• Optimum planting time
• Seeding depth
• Seed vigor (Quality testing)
• Fertilizer timing
• Pest and disease management
35. Seedbanks- the seed in your paddock
• Surviving weeds set seed
• Low numbers of resistant weeds can set lots of seeds
• Seed longevity
– Differs between species
– Left on surface vs burial (tillage systems)
