This document discusses herbicide resistance issues in no-till farming systems. It notes that glyphosate resistance has become widespread in many weed species in Australia, with over 130 confirmed resistant ryegrass populations. Multiple resistance to multiple herbicide modes of action is also present in some weed species. Glyphosate resistance is an increasing problem due to heavy reliance on glyphosate in genetically modified glyphosate-resistant crops. The document advocates an integrated approach using diverse herbicides and harvest weed seed control methods to reduce selection pressure for resistance and sustain glyphosate effectiveness.

1. Herbicide Resistance In No
Tillage Farming Systems
Dr David Minkey
david.minkey@wantfa.com.au
www.wantfa.com.au

2. Sustaining no-till & glyphosate
D’Emden et al 2009

3. Resistance Surveys
Frequency of herbicide resistance
in Western Australia
Mechelle Owen, Michael Walsh & Stephen Powles
Australian Herbicide Resistance Initiative
www.ahri.uwa.edu.au

4. Crop variety testing zones
30 plus sites visited
in each region
Sampled
every 5km
H

5. Multiple Resistant Annual Ryegrass Populations

6. Multiple resistance Wild Radish
84%
H1/M1/L1
65%
H2/M2/L2
39%
H3/M3/L3
28%
H4/M4/L4

7. Years to resistance for different herbicides - USA
35
ALS Inhibitors
30
25
Resistant species
20
ACCase inhibitors
15
Triazines
10
5

Glyphosate
0
0 10 20 30 40 50
Years of use

8. (Roundup) glyphosate @ 450g/ha
R S

9. (Gramoxone) paraquat @ 200g/ha
R S

10. (Hoegrass) diclofop @ 1000g/ha
R S

11. (Verdict) haloxyfop @ 52g/ha
R S

12. (Fusilade) fluazifop @ 100g/ha
R S

13. (Achive) tralkoxydim @ 152g/ha
R S

14. (Sertin) sethoxydim @ 100g/ha
R S

15. The Rise and Rise of
Glyphosate
Australian Herbicide Resistance Initiative
University of Western Australia

16. Glyphosate: a once in a
life time herbicide
“Glyphosate is as important to
world agriculture as penicillin is
to human health” Powles 2010

17. 2009 Global Herbicide Sales
Source: Cropnosis Ltd
Atrazine
Nicolsulfuron
Clodinafop
Fenoxaprop
S-Metalochlor
Mesosulfuron
2,4-D
Acetochlor
Glufosinate
Mesotrione
Paraquat
Glyphosate
0 1000 2000 3000 4000 5000 600
Sales ($m)

18. $ 5 billion
19
74
19
76
19
78
19
80
19
82
19
84
19
86
Knockdown use
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
20
06
History of glyphosate
20
08
Introduction of RR Crops
20
10

19. Global GM Crops (million ha)
•Soybean, maize, cotton and canola
•90% RR
160
•80% globally traded soybeans are RR
140
120
•60% globally traded canola are RR
100
80
60
40
20
0
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Source: ISAAA

20. Argentine GM soybeans v No-till No-till
Argentine RR soybeans & farming
16 20
GM Soybeans
RR Soybeans
No-till Farming (m ha)
16
GM Soybeans (m ha)
12 No-till farming
12
8
8
4
99% RR 4
0 0
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Trigo J & Cap J

21. How to be in
herbicide resistance

22. Corn, Cotton
and Soybean
Belt
Corn 40 m ha
Soybean 30 m ha
Cotton 5 m ha

23. Corn, Cotton
and Soybean
Belt
Corn 40 m ha (85% glyphosate resistant)
Soybean 30 m ha (95% glyphosate resistant)
Cotton 5 m ha (95% glyphosate resistant)

24. RR soybean removed previous
herbicide diversity

25. GLYPHOSATE
BELT

26. Palmer Amaranth inin RR Cotton
Palmer Amaranth RR Cotton

27. Learning from GM cropping in Canada
Cereal, Canola
Corn/Soy

28. Learning from Canada
• Wheat the major crop
• GM Canola dominant but with diversity
- Liberty Link Canola
- Clearfield Canola
- RR Canola – 80%
Diversity in crops and herbicides=
Sustainability

29. Glyphosate Resistance in Australia
 133 cases of resistant ryegrass
State No of populations
SA 49
NSW 48
WA 22
Vic 14
 Other Species - Liverseed grass (3)
- Awnless barnyard grass (18)
- Windmill grass (1)
- Fleabane (8)
Photo: Andrew Heinrich

30. Glyphosate resistance
• Not limited to broadacre situations resistance has
been found in:
• Vineyards
• Orchards
• Roadside verges
• Railway lines
• Irrigation channels
• Airstrips
• Fencelines/crop margins – using glyphosate as
only method for weed control will lead to evolution
of resistance
GLYPHOSATE STILL WORKING ON
MOST FARMS – KEEP IT THAT WAY
Photo: Andrew Heinrich

31. Probability of glyphosate resistance
1
Glyphosate every year
Probability of resistance
0.8 Glyphosate/paraquat rotation
Glyphosate then paraquat sequence
0.6
0.4
0.2
0
0 5 10 15 20 25 30
Year
Neve et al 2003 weed research
Cumulative probability distributions for predicted evolution of glyphosate resistance in annual ryegrass
in a 30-year simulation of a Wheat-Lupin-Wheat-Canola rotation with no tillage at sowing

33. Harvest weed seed
mgt, double knock!
• Up to 85% of ryegrass seed “harvested”
can be collected in the chaff fraction

35. Burn Narrow windrows

36. HSD – double knock
Photo: Piers Blake

37. Bale everything!!

39. 300
250
Wild radish seed (m 2)
200
No cart
Cart
150
100
50
0
-10 0 10 20 30 40 50 60 70 80 90 100 110
Distance (m)

40. Targeting weed seeds allows
crop production to continue
- Chaff collection
- Harvest residue baling
- Windrow burning
- Chaff destruction