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Glyphosate Resistance And The
Impact On Agriculture
Jeff StachlerExtension Agronomist – Sugarbeet / Weed Science
NDSU and U of MN12-13-12
Dr. Jeff Stachler
Presentation outline
1. Why should we care about weed resistance??
2. The situation in ND and MN
3. Defining high-level & low-level resistance
4. General solutions
Dr. Jeff Stachler
Why should we care about weed resistance?
• No new novel herbicide site / mechanism of action is expected for the next 5 to 10 years!
• Reduced profits if resistant biotypes selected
• Weed resistance, most importantly multiple resistance continues to increase
Dr. Jeff Stachler
Why should we care about weed resistance? – Lost profit
$12.00/A
Roundup PowerMAX
(32 / 22 / 22 fl oz/A )
$145/A
Ro-Neet (5.3 pt/A) [PPI] fbBetamix (12 / 16 / 24 fl oz/A) +
Nortron (4 fl oz/A) +Outlook (14 / 10 fl oz/A) +
Roundup PowerMAX(32 / 22 / 22 fl oz/A )
+ $133/A
Dr. Jeff Stachler
Why should we care about weed resistance?
2009 2011near Prinsburg, MN
Crystal: 81% growers reported Excellent weed control with glyphosate
SMBSC: 59% ExcellentSMBSC
CrystalCrystal: 90% growers reported Excellent weed control with glyphosate
SMBSC: 76% Excellent
Dr. Jeff Stachler
The Situation
Gly-R common ragweedGly-R giant ragweedGly-R waterhemp
Areas and counties of ND and MN havingconfirmed and suspected glyphosate-resistant weeds
2007
Black symbols: confirmed resistant cases; Blue: highly suspectedProvided by: Drs. Jeff Stachler, Jeff Gunsolus, Mike Christoffers, and Kirk Howatt
Gly-R common ragweedGly-R giant ragweedGly-R waterhemp
50 to 95% all fields have gly-R G. Rag.
30 to 60% all fields gly-RC. Rag.
5 to 90% all fieldsgly-R waterhemp
10 to 40% soybean fieldsgly-R C. Rag.
Areas and counties of ND and MN havingconfirmed and suspected glyphosate-resistant weeds
30 to 90% all fields have gly-R waterhemp
2010
Black symbols: confirmed resistant cases; Blue: highly suspectedProvided by: Drs. Jeff Stachler, Jeff Gunsolus, Mike Christoffers, and Kirk Howatt
25 to 40% soybean fields gly-R C. Rag.
Dr. Jeff Stachler
Waterhemp - Holloway, MN – 2010two glyphosate applications
Gly-R horseweed / marestailGly-R kochiaGly-R common ragweedGly-R giant ragweedGly-R waterhemp
Black symbols: confirmed resistant cases; Blue: highly suspectedProvided by: Drs. Jeff Stachler, Jeff Gunsolus, Mike Christoffers, and Kirk Howatt
Areas and counties of ND and MN havingconfirmed and suspected glyphosate-resistant weeds
2011 70 to 95% all fields gly-RC. Rag.
30 to 60% all fields gly-RC. Rag.
60 to 95% all fields have gly-R G. Rag.
70 to 95% all fields have gly-R waterhemp
5 to 95% all fieldsgly-R waterhemp
5 to 95% all fields gly-RG. Rag. & waterhemp
5 to 50% soybean fields gly-R C. Rag.
Dr. Jeff Stachler
Waterhemp - Moorhead, MN – 2011two glyphosate applications
Dr. Jeff Stachler
Waterhemp & common ragweed - SW Traill Co., ND - 2011
Waterhemp
Dr. Jeff Stachler
Common ragweed - E. of Nielsville, MN - 2011
Bettermanagement
ContinuousRR soybean
ContinuousRR soybean
Bettermanagement
Dr. Jeff Stachler
Glyphosate-resistant kochia – Stutsman and Pierce Co., ND – 2011 (least activity)
Stutsman Co., ND Population
Susceptible Check
UntreatedCheck
0.375 lb ae/ARndp 10.7 fl oz/A
6 lb ae/ARndp 1.3 gal/A
3 lb ae/ARndp 85 fl oz/A
1.5 lb ae/ARndp 43 fl oz/A
1.125 lb ae/ARndp 32 fl oz/A
0.75 lb ae/ARndp 21.3 fl oz/A
0.56 lb ae/ARndp 16 fl oz/A
Pierce Co., ND Population
Gly-R horseweed / marestailGly-R kochiaGly-R common ragweedGly-R giant ragweedGly-R waterhemp
Black symbols: confirmed resistant cases; Blue: highly suspectedProvided by: Drs. Jeff Stachler, Jeff Gunsolus, Mike Christoffers, and Kirk Howatt
Areas and counties of ND and MN havingconfirmed and suspected glyphosate-resistant weeds
2012
5 to 95% all fieldsgly-R waterhemp
5 to 95% all fields gly-RG. Rag. & waterhemp
15 to 90% soybean fields gly-R C. Rag.
5 to 60% all fields have gly-R kochia
Dr. Jeff Stachler
Glyphosate-resistant kochia - Richland County, ND - 2012
Photo from: Ingrid Kristjanson
Dr. Jeff Stachler
Glyphosate-resistant kochia - McIntosh County, ND – 2012Also present: Horseweed (marestail), and Lambsquarters
= kochia = horseweed
Dr. Jeff Stachler
Locations of Run 1 samples tested – 11-12
Dr. Jeff Stachler
2012 Glyphosate-R test results0.75 lb ae/A
Rndp 21.3 fl oz/A2.25 lb ae/A
Rndp 64 fl oz/A
Richland Co., ND Population
Benson Co., ND Population
Susceptible Check
R
S
Currently 29% of 38 samples have tested positive
Dr. Jeff Stachler
2012 Glyphosate-R test results0.75 lb ae/A
Rndp 21.3 fl oz/A2.25 lb ae/A
Rndp 64 fl oz/A
Logan Co., ND Population
Benson Co., ND Population
Susceptible Check
R
S
Dr. Jeff Stachler
Glyphosate-resistant horseweed in Cass County, ND
2011 - <1% of field
2012 - 60% of field + 2 other fields
Dr. Jeff Stachler
Additional herbicide resistance issues
1. Fluroxypyr-R kochia1. Present in 20 to 50% of fields in Central ND
Dr. Jeff Stachler
Dicamba and fluroxypyr-resistant kochia – Pierce Co., ND 2011 seed
Higher ground (no salt)
UntreatedCheck
Atrazine0.5 lb ai/A
Clarity8.0 fl oz/A 2.86 fl oz/A
Clarity4.0 fl oz/A
Salt spot
5.7 fl oz/A
11.4 fl oz/A
22.8fl oz/A
Starane Ultra
Counties of ND and MN havingconfirmed fluroxypyr (Starane)-resistant kochia
2011
Black symbols: confirmed resistant cases; Blue: highly suspectedProvided by: Drs. Jeff Stachler, Jeff Gunsolus, Mike Christoffers, and Kirk Howatt
100% (2/2) = R
Dr. Jeff Stachler
2012 Fluroxypyr-R test results0.12 lb ae/A (1.9 oz ae)Starane Ultra 5.5 fl oz/A
0.25 lb ae/A (4 oz ae)Starane Ultra 11.4 fl oz/A
Cavalier Co., ND Population
Benson Co., ND Population
Susceptible Population
R
S
Counties of ND and MN havingconfirmed fluroxypyr (Starane)-resistant kochia
2012
Black symbols: confirmed resistant cases; Blue: highly suspectedProvided by: Drs. Jeff Stachler, Jeff Gunsolus, Mike Christoffers, and Kirk Howatt
63% (12/19) = R
Dr. Jeff Stachler
Additional herbicide resistance issues
1. Fluroxypyr-R kochia ???1. Potentially present in 20 to 50% of fields in Central ND
2. PPO-R common ragweed and giant ragweed1. Likely present in Mahnomen Co., MN
Dr. Jeff Stachler
Conventional Soybean in Mahnomen County, MN - 2012Flexstar (0.75 pt/A) 2 times
Dr. Jeff Stachler
Additional herbicide resistance issues
1. Fluroxypyr-R kochia ???1. Potentially present in 20 to 50% of fields in Central ND
2. PPO-R common ragweed and giant ragweed1. Likely present in Mahnomen Co., MN
3. Bentazon-R biennial wormwood ??? (ND)4. Multiple herbicide resistance
1. PPO + ALS + glyphosate in waterhemp (MN & ND)2. ALS + PPO + triazine + glyphosate in waterhemp (MN)3. Fluroxypyr/dicamba/2,4-D + glyphosate in kochia (ND)4. PPO + ALS in common ragweed (ND)5. ACCase + ALS in wild oat and green foxtail (ND & MN)
5. Others ??
Dr. Jeff Stachler
Multiple resistance???Cobra applied near Holloway, MN
Dr. Jeff Stachler
Multiple-resistant waterhemp
Untreated
Flexstar+ MSO+ AMS
1 pt3 pt
UltraBlazer+ MSO+ AMS
Sharpen+ MSO+ AMS
Cadet+ MSO+ AMS
Resource+ MSO+ AMS
Cobra+ MSO+ AMS
4.5 pt 2 oz6 oz
0.9 oz2.7 oz
3 oz9 oz
12.5 oz
37.5 oz
1.5 pt
SusceptibleCheck
Holloway,MN
ResistantCheck
(IL)
Dr. Jeff Stachler
Multiple-resistant waterhemp
Flexstar GT 3.5+ MSO+ AMS
3.5 pt
Aatrex+ MSO+ AMS
Callisto+ MSO+ AMS
HarmonyGT+ MSO+ AMS
Callisto+ Aatrex+ MSO+ AMS
TouchdownHiTech+ R-11+ AMS
3 qt3 oz
9 oz0.38 oz 3 oz
+ 1pt19 oz
58 oz1 qt
10.5 pt9 oz+ 3 pt
SusceptibleCheck
Holloway,MN
ResistantCheck
(IL)
Dr. Jeff Stachler
Dr. Jeff Stachler
Untreated
Flexstar
+ FirstRateGlyphosate
+ Flexstar
+ FirstRate
Glyphosate
+ FirstRate
Glyphosate
+ Flexstar
OH
Progeny
Susceptible
1X 4X 1X 4X1X 4X1X 4X
Size at time of application
Dr. Jeff Stachler
Multiple-resistant kochia - 2012
Cavalier Co., ND Population
Benson Co., ND Population
Susceptible Population
0.75 lb ae/ARndp 21.3 fl oz/A
2.25 lb ae/ARndp 64 fl oz/A
0.12 lb ae/A (1.9 oz ae)Starane Ultra 5.5 fl oz/A 0.25 lb ae/A (4 oz ae)
Starane Ultra 11.4 fl oz/A
R
S
Dr. Jeff Stachler
Defining High-Level & Low-Level Resistance
Dr. Jeff Stachler
• High-Level Resistance = Survival at rates > 10 timesthe labeled rate
– Application parameters (coverage, environment, etc.) unlikely to affect control of species!!
– Usually minimal injury
– The correct rate usually does not matter when initiallyselecting
– Second applications usually do not reduce seed production!
– Usually single gene change of target site
– Examples = triazine, ALS, and ACCase
Types of Herbicide Resistance
Dr. Jeff Stachler
Types of Herbicide Resistance
• Low-Level Resistance = Survival at rates < 10 times the labeled rate
– Many different application parameters (coverage, environment, etc.) likely to affect control of species!!
– Significant injury always occurs initially & CAN kill small plants
– The correct rate DOES matter when initially selecting!!!
– Second applications USUALLY REDUCE numbers of plants & seed production!
– May be multiple or single gene changes in target site or other sites
– Examples = glyphosate, PPO, synthetic auxins, paraquat
Dr. Jeff Stachler
Take-home message about resistance vs. tolerance
• Resistance– A change in response in the weed populations to the
herbicide.– Resistant biotypes will increase over time.
• Tolerance– No change in response in the weed population to the
herbicide.– Tolerant species should increase more rapidly than
resistant biotypes.
Solutions
Dr. Jeff Stachler
Solutions to weed resistance
• Scout 5 to 14 days after EACH herbicide application.
• Observe individual plant responses!!
Response of a resistant waterhemp population
DeadInjuredNormal
Continuous response of common ragweed to glyphosate
Picture from Al Cattanach
Dr. Jeff Stachler
Dead (40%)
Nearly Dead (36%)
Intermediate (9%)
Best survivors (14%)
Resistant
Continuous response of a susceptible kochia population to glyphosate
Dr. Jeff Stachler
Continuous response of kochia to glyphosate
Dr. Jeff Stachler
Continuous response of kochia to glyphosate
Website address for video “Scouting for Glyphosate Resistance”:
http://www.ag.ndsu.edu/weeds/herbicide-resistant-weeds
Solutions - Understand Impact of ONE Weed
Dr. Jeff Stachler
Single waterhemp plant in 2011 (Clay County, MN)actual seed number per plant = 142,000
Scenario: seed number on 1 plant in 1 acre =100,000 seeds
Dr. Jeff Stachler
Scenario
• If 25% (40% is possible) of seeds emerge next season (2012)
• Only 10% of emerged plants are resistant• Same herbicide is applied as previous year• How many plants may be present in 1 acre at
the end of the season (2012)?
Dr. Jeff Stachler
2,500 plants/A – 1 year later (2012)
Dr. Jeff Stachler
6,250,000 plants/A!! - 2 years later (2013)
Field perimeter management (2010)
Dr. Jeff Stachler
Ramifications of not managing field perimeter (2011)
Dr. Jeff Stachler
Ramifications of not managing field perimeter (2012)
Dr. Jeff Stachler
Management of weeds along crop edges
Future problem! The Goal!
Solution – Practice ZERO TOLERANCE (no seed rain)
• Hand-weeding– Remove / destroy surviving plants by hand from a
field, especially when there are just a few!– There in no better way to STOP the increase of
resistant biotypes.
• Or row cultivate and hand-weed
Single plant Small patch
Dr. Jeff Stachler
Solution – Practicing ZERO TOLERANCE (no seed rain)
• 52% of AR cotton hand-weeded in 2011– Average cost = $29.43/A (beets = $21.00/A)– Proactive hand-weeding - $4-5/A
• 2010 hand-weeding – 110 hours/50 acres ($22/A)• 2011 hand-weeding – 5 hours/50 acres ($1/A)
ND Grower Website – Stewardship Practices:Weed Control – We strive to manage weeds to provide nearly 100% weed control in all crops and even those on the perimeter. We’re tough on weeds, but not on the land.
IL Land Lease:Weed Control – The Landlord and Tenant agree that control of weeds is an extremely important aspect of crop production. … If herbicidal treatment fails to control weeds and subsequent retreatment(s) also fail, then Tenant shall be solely responsible to use mechanical methods to control weeds including but not limiting to hand hoeing, hand pulling, and cultivation. Tenant … that will minimize the risk of for resistance weeds.
Dr. Jeff Stachler
Solution – Practicing Zero Tolerance
• 1 hr/50 A = 0.02 hr/A
• 0.02 hr/A X 5000 A = 100 hrs
• 100 hrs 10 hrs/day = 10 days
• 100 hrs X $10/hr = $1,000
• Vs $133/A X 5000 A = $665,000• Vs $20/A X 5000 A = $100,000
Dr. Jeff Stachler
Solution – Respond quickly!
Dr. Jeff Stachler
Solution – Understand impact of weed seed movement
• Means of dispersal:– Water (especially for waterhemp)– Machinery– Wind– Humans– Animals / birds
MPR Photo/Ann Arbor Miller
Dr. Jeff Stachler
Movement of waterhemp seeds by 2011 flood
To McLeod, ND15 mi. upstream
Direction of water movement
Dr. Jeff Stachler
Solutions
• Diversify weed management– Greater crop rotation– Start clean!– Use PRE herbicides in ALL crops– Rotate herbicide mechanisms of action– Tank-mix PRE and POST herbicides– Maximize herbicide activity
• Apply POST herbicides to small (< 3” weeds)• Optimize coverage• Use best adjuvant(s) and at highest rate
– Maximize cultural practices• Maximize quick crop canopy closure
Dr. Jeff Stachler
Control of glyphosate-R common ragweed – Mayville – 9-25
Herbicide Program RR Soy LL SoyRoundup / Liberty (2 times) 58 96Roundup / Liberty + Flexstar/Cobra/Cadet fb Rndp / Lib 73 (93/34) 98Roundup / Liberty + Outlook + Cobra fb Rndp / Lib 68 95PRE*** fb Roundup / Liberty (2 times) 78 99PRE** fb Roundup / Liberty + Flexstar fb Rndp / Lib 95 99PRE* fb Roundup / Liberty + Cobra + Outlk/Wrrnt fb Lib 99 99
*** 1. Boundary (1.8 pt/A) {59%}2. Prefix (1.75 pt/A) {69%}3. Valor (2.5 oz/A) + Dimetric (5.33 oz/A)
{76%}4. Fierce (3.0 oz/A) {44%}5. Sharpen (1 fl oz/A) + Zidua (2.5 oz/A)
{67%}6. Verdict (5 fl oz/A) + Zidua (2.5 oz/A)
{68%}
** 1. Boundary (1.8 pt/A)2. Verdict (5 fl oz/A) + Zidua (2.5 oz/A)
*1. Verdict (5 fl oz/A) + Zidua (2.5 oz/A)
Dr. Jeff Stachler
Yield of RR/LL soybean - Mayville
Herbicide Program RR Soy LL Soy% of Roundup alone
Roundup / Liberty (2 times) 100(8.1 bu/A)
122
Roundup / Liberty + Flexstar/Cobra/Cadet fb Rndp / Lib 104 122Roundup / Liberty + Outlook + Cobra fb Rndp / Lib 99 122PRE fb Roundup / Liberty (2 times) 133 133PRE fb Roundup / Liberty + Flexstar fb Rndp / Lib 146 165PRE fb Roundup / Liberty + Cobra + Outlk/Wrrnt fb Lib 135 123
Dr. Jeff Stachler
Herbicide, adjuvant, app., & seed costs - Mayville
Herbicide Program RR Soy LL Soy$ (% of Glyphosate alone)*
Roundup / Liberty (2 times) 88 (100%-$25)
95 (174)
Roundup / Liberty + Flexstar/Cobra/Cadet 106 (46) 108 (122)Roundup / Liberty + Outlook + Cobra fb Rndp / Lib 114 (-8) 118 (82)PRE fb Roundup / Liberty (2 times) 112 (157) 119 (129)PRE fb Roundup / Liberty + Flexstar 125 (161) 134 (214)PRE fb Roundup / Liberty + Cobra + Outlk/Wrrnt fb Lib 143 (38) 150 (-40)
App. Fee = $5.00/A/app.Seed costs = $60.84 (RR) & $51.81 (LL)
Soybean price = $14.00
Cost (Profit)*
Dr. Jeff Stachler
Final reminders
• You have a choice!–Delay resistance OR Ignore it
Final reminders - Leave a Legacy!
• The future success of your farming operation depends upon the weed control practices you choose today!
• Glyphosate is the most effective herbicide ever discovered, so let’s work together to preserve it’s effectiveness! THE Goal!
Dr. Jeff Stachler
• Thank You!
• ANY questions?
• Contact information– [email protected]– 701-231-8131 (Office)– 218-790-8131 (Cell)
• Resources– http://www.ag.ndsu.edu/weeds/– http://www.sbreb.org/