Current and future role of the non-selective use of glyphosate

1. Roundup Ready Maize symposium: The European Perspective
Current and future role of the
non-selective use of glyphosate
Jim Orson
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2. Roundup Ready Maize symposium: The European Perspective
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3. Roundup Ready Maize symposium: The European Perspective
“All our attempts at couch control by
cultivation have been fruitless.”
Andrew Charlton, Farmer’s Weekly
January 2009
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4. Roundup Ready Maize symposium: The European Perspective
Glyphosate
• 1974 - introduced in UK for perennial weed control
• 1980 - pre-harvest application introduced
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5. Roundup Ready Maize symposium: The European Perspective
Reduction (%) of common couch shoots in the following
season after pre-harvest or post-harvest application of
a range of doses (kg ae/ha) of glyphosate in 1979 in
Scotland (Source; O’Keeffe et al., 1981)
Site Pre-harvest Post-harvest
0.72 1.44 0.72 1.44
1 99.7 99.7 95.1 97.8
2 98.8 98.4 64.5 89.6
3 99.4 99.2 31.6 93.7
4 - 90.0 - 60.0
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6. Roundup Ready Maize symposium: The European Perspective
Glyphosate – a few properties
Solubility in water (20oC) = 10,500 mg/l
Koc = non-mobile
GUS leaching potential index = -0.36
Potential for particulate bound transport = medium
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7. Roundup Ready Maize symposium: The European Perspective
UK competitiveness based on technology
Average wheat yields (t/ha)
t/ha Effective
9
Effective fungicides
8
herbicides
7
6
5 Increase in N
4
3
2
Semi-dwarf
1
varieties
0
68
73
78
83
88
93
98
03
08
19
19
19
19
19
19
19
20
20
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8. Roundup Ready Maize symposium: The European Perspective
% of winter wheat in England established
after non-plough tillage
45
40
35
30
25
20
15
10
5
0
19 5
19 6
19 7
19 8
19 9
19 0
19 1
19 2
19 5
19 6
19 7
19 8
19 9
19 0
19 1
19 2
19 3
19 4
19 5
19 6
19 7
19 8
20 9
20 0
20 1
20 2
20 3
20 4
20 5
20 6
20 7
08
7
7
7
7
7
8
8
8
8
8
8
8
8
9
9
9
9
9
9
9
9
9
9
0
0
0
0
0
0
0
0
19
Source:
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9. Roundup Ready Maize symposium: The European Perspective
% of winter wheat crops in England sown in September and
before 20th September, 1970-2008 harvest years
60
50 September
Before 20/09
Crops drilled (%)
40
30
20
10
0
70
72
74
76
78
80
82
86
88
90
92
94
96
98
00
02
04
06
08
19
19
19
19
19
19
19
19
19
19
19
19
19
19
20
20
20
20
20
Source:
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10. Roundup Ready Maize symposium: The European Perspective
Glyphosate
• Introduced in UK for perennial weed control in
1974
• Pre-harvest application introduced in 1980
And then it got cheaper!
• Subsequently used for annual grass and
broad-leaved weed control and crop
dessication
• Glyphosate residues commonly occur in UK
bread (below MRLs)
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11. Roundup Ready Maize symposium: The European Perspective
Percentage of bread samples (ordinary and speciality)
containing glyphosate residues, 2000-2006
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12. Roundup Ready Maize symposium: The European Perspective
Wheat yield (t/ha @ 85% MC) and moisture content (%) of
grain at harvest of Consort wheat, treated or not treated with
1.0 l/ha Roundup (360 g ae/l glyphosate) when the bulk grain
content of the site was 30% moisture content; Morley 1999
Fungicide programme 1.0 l/ha Yield % moisture
Roundup (t/ha)
No No 6.52 18.23
No Yes 6.32 14.96
Non-strob No 7.31 17.34
Non-strob Yes 6.81 14.91
Strob No 8.44 17.01
Strob Yes 7.68 15.45
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13. Roundup Ready Maize symposium: The European Perspective
Wheat yield (t/ha @ 85% MC) and moisture content (%) of
grain at harvest of Consort wheat, treated or not treated with
1.0 l/ha Roundup (360 g ae/l glyphosate) when the bulk grain
content of the site was 30% moisture content; Morley 1999
Fungicide programme 1.0 l/ha Yield % moisture
Roundup (t/ha)
No No No 6.52 18.23
No Yes impact6.32
on 14.96
Non-strob MOG No quality
7.31 17.34
Non-strob Yes in clean
6.81 14.91
Strob No crops8.44 17.01
Strob Yes 7.68 15.45
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14. Roundup Ready Maize symposium: The European Perspective
% of winter wheat in England established
after non-plough tillage
45
40 The value
35 of stale
30 seedbeds?
25
20
Cereals
15 Rye-grass
10 Barren brome
5 Meadow brome - Seeds can
0 No be lost
Black-grass? without
19 5
19 6
19 7
19 8
19 9
19 0
19 1
19 2
19 5
19 6
19 7
19 8
19 9
19 0
19 1
19 2
19 3
19 4
19 5
19 6
19 7
19 8
20 9
20 0
20 1
20 2
20 3
20 4
20 5
20 6
20 7
08
7
7
7
7
7
8
8
8
8
8
8
8
8
9
9
9
9
9
9
9
9
9
9
0
0
0
0
0
0
0
0
19
Wild-oats? creating
Source:
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15. Roundup Ready Maize symposium: The European Perspective
Post-drilling use
• Convenience – rather than improved weed
control
• Maize in France:
– up to 48 hours after drilling provided soil has more
than 10% clay (<24 hours and max dose of less
than 360 g ae/ha if soil is sandy)
– soil well structured and seed well covered
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16. Roundup Ready Maize symposium: The European Perspective
Most likely active substances to fail re-registration as
a result of the revision of 91/414
• 2,4-D? (2011) • Flumioxazine (2012) • Metribuzin? (2017)
• Amitrole?? (2011) • Fluquinconazole? (2020) • Pendimethalin (2013)*
• Carbendazim (2009)* • Flusilazole (not sure) • Picloram? (2018)
•
•
Carbetamide? (2020)
Chlorotoluron? (2016)
• plus
Glufosinate (2017) • Prochloraz? (2020)
• Prothioconazole? (2018)
• Ioxynil?? (2015)
• Cyproconazole??
(2020) •
Water
Ipridione?? (2013)
• Quinoxyfen (2014)*
• Tebuconazole?? (2018)
•
•
Deltamethrin? (2013)
Dimethoate? (2016)
• Framework
Linuron (2013) • Tepraloxydim? (2015)
• Thiram? (2013)
• Mancozeb?? (2016)
•
•
Dinocap (2009)
Epoxiconazole??
• Directive
Maneb?? (2016) • Triflusulfuron? (2018)
(2018) • Metconazole?? (2017)
* = no derogation
• Esfenvalerate (2011)*
? = endocrine disruptor on PSD assessment
?? = endocrine disruptor on both PSD and Swedish assessment
Other active substances may be subject to candidates for substitution
– particularly most insecticides
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17. Roundup Ready Maize symposium: The European Perspective
% reduction in black-grass heads from the application of
2,500 g/ha isoproturon at GS 11-13 of the weed – individual
TAG trials 1996-2007 (blue) and average (green)
100
90
80
70
60
50
40
30
20
10
0
19
19
19
19
20
20
20
20
20
20
20
20
96
97
98
99
00
01
02
03
04
05
06
07
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18. Roundup Ready Maize symposium: The European Perspective
% reduction in black-grass heads from the application of 2.5
l/ha Hawk at GS 11-13 of the weed – individual TAG trials
1996 – 2004 (blue) and average (green)
100
90
80
70
60
50
40
30
20
10
0
19
19
19
19
20
20
20
20
20
96
97
98
99
00
01
02
03
04
No. trials text 3
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4 5 6 8 8 9 6 3

19. Roundup Ready Maize symposium: The European Perspective
Cases of resistance to ‘Atlantis’
(mesosulfuron+iodosulfuron) in
black-grass in the UK by 2008
(‘Atlantis’ introduced autumn 2003)
• >250 cases confirmed in pot tests
• In 21 counties
• Most not ‘field failures’
• Target site resistance (Pro197) confirmed on 10
farms
• Target site resistance (Trp574) confirmed on 1 farm
• Both target site mutations
(Pro197 & Trp574 ) on 1 farm
• Enhanced metabolism also probable
• 79% also ACCase (‘fop’/‘dim’) TSR
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Compilation of Bayer, Syngenta and Rothamsted results

20. Roundup Ready Maize symposium: The European Perspective
The future – do we need a Plan B?
• Need to embrace new technologies (e.g.
remote sensing and GM) in addition to
refining current technologies to reduce
dose/ha of key active substances
• Need to build up fertility in soils in order to:
– sustain/increase yields
– increase flexibility of cropping
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21. Roundup Ready Maize symposium: The European Perspective
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22. Roundup Ready Maize symposium: The European Perspective
Glyphosate
35 years on and still developing new
uses and approaches
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