Post on 11-Jan-2016
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2014: Herbicide Resistance Changes Agriculture Forever
Stanley CulpepperTifton, GA
Herbicide-resistance is not a new phenomenon!Its been happening since 1968!
The U.S. Wins the Gold Medal in Herbicide Resistance!!!!
Source: International Survey of Herbicide Resistant Weeds (10/4/12)
Confirmed Cases of Herbicide-Resistant Weeds in the United States
5
5
1119
1165
6
9
2
Source: International Survey of Herbicide Resistant Weeds (10/4/12)
24 20
8
26 4
CT-2DE-7HI- 4MD-11MA-2NH-2NJ-4RI-1VT-2
13
22 1622
22 4
2
27
17
13
10
8
5
13
21
18
7
10
1
11
122
Resistance Development
Economics, Effectiveness, and Ease of the
herbicide(s)
AND
Biology of the weed
Roundup Ready
Technology
Very Economical
Very Effective
Extremely Easy
Resistance Development
Economics, Effectiveness, and Ease are almost always the main factors
1. Single mode of action applied to large acreage2. Few or no alternative classes of chemistry used3. Little to no tillage4. Little to no rotation in crops5. Often in stressful environments when herbicide activity
is minimized6. Reduced herbicide rates, poor coverage, etc.. that
minimize activity
Tremendous Selection Pressure
Selection Pressure
Overuse of herbicide chemistry
Resistance
Herbicide Resistance: The acquired (inherited) ability of a weed population to survive a herbicide application that previously was known to control the population.
Palmer amaranth Changes Agriculture
Biological Attributes
Herbicide Resistance
2005-2011
What makes Palmer special?
1. Herbicide resistance?
Oh my, how great it was!!!!!!
WeatherMax 176 oz; POST 2”, 5”, and 8”
(at least 24 times more lb active than normally needed)
cotton
Weathermax 88 oz
Staple LX 10 oz
What makes Palmer special?
1. Herbicide resistance?
2. Growth rate?
Picture taken 7 am on 7-9-07
4 inches 52 hr
Picture taken 7 am on 7-9-07
1/2 inch 12 hr (overnight)
What makes Palmer special?
1. Herbicide resistance?
2. Growth rate?
3. Large stature?
Rapid Growth Becoming Extremely Large
What makes Palmer special?
1. Herbicide resistance?
2. Growth rate?
3. Large stature?
4. Competitive ability?
Crop Rotation
Yield Loss (%) from 1 AMAPA/row meter
What makes Palmer special?
1. Herbicide resistance?
2. Growth rate?
3. Large stature?
4. Competitive ability?
5. Reducing harvest efficacy?
Impact on Harvest
What makes Palmer a special?
1. Herbicide resistance?
2. Growth rate?
3. Large stature?
4. Competitive ability?
5. Reducing harvest efficacy?
6. Seed production?
0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
450,000
500,000
230 K
25028 K
309 K
Giant ragweed
450 K
Number of Seed Produced per Plant Glyphosate-Resistant Weeds in US
Ragweed = Harrison et al. 2001; johnsongrass = Warwick and Black (1983); horseweed = Regehr and Bazzaz (1979); waterhemp = Nordby and Hartzler (2004); Palmer amaranth = Macrae et al (2009).
Johnson-grass
Horseweed Waterhemp Palmer amaranth
Palmer amaranth seed production allows for rapid field domination
Year 1 Year 3 to 4
What makes Palmer special?
1. Herbicide resistance?
2. Growth rate?
3. Large stature?
4. Competitive ability?
5. Reducing harvest efficacy?
6. Seed production?
7. Rapid spread?
Role of pollen movement and gene-flow in the spread of herbicide resistance
Pollen-flow can move genes across the landscape
And a trait becomes established in a new population
Traditional Grower Response To Resistance
1. It want happen to me!
2. Ok, its starting to happen to me so when will the next new
herbicide be here? (1992 was last new mode of action)
3. O *$&#, I got a mess. It’s on!
Traditional Grower Response To Resistance
1. It want happen to me!
2. Ok, its starting to happen to me so when will the next new
herbicide be here? (1992 was last new mode of action)
3. O *$&#, I got a mess. It’s on!
The challenge for Extension and Industry is figuring out how to skip steps 1 and 2 moving straight into step 3.
Helping Growers Respond More Quickly
1. Unified communication
2. Unbiased research defining potential impact from resistant
weed.
3. Provide management programs that are as simple and
economical as possible.
Herbicide input increased from 4.25 to 10.625 lb ai/A
2000-2005: Herbicide costs = $27.80/A
2006-2010: Herbicide costs = $68.00/A
Changes in Herbicide Management2002: $24/A 2010: $63/A
Roundup Burndown
Roundup POST 1
Roundup POST 2
Roundup + diuron PD
Roundup + Valor Burndown1
Gramoxone + Reflex + Direx PRE
Roundup + Staple POST 1
Roundup + Dual POST 2
Direx + MSMA PD
Photo by A.C. York 2010
2004: 17% of growers hand-weeded 5% cotton acres at $2.40/A
2010: 92% of growers hand-weeded 52% cotton acres at $23.70/A
Tillage is now a common scene
2004: 13.1% of cotton acres cultivated2010: 32.1% of cotton acres cultivated
Herbicide incorporation: 264,266 A (26.7%) Deep turn: 256,075 A last 3 yr
Current Cotton Situation
Cost to Manage Palmer in GA Cotton
1. Herbicide input: $68.00 per A $88 million
2. Hand weeding: $11.40 per A $15 million
3. Additional tillage: $5.84 per A $7.6 million
4. Yield loss ??? ????
$110 million
RR Herbicide Program Getting Better*
2010 2012
*Conditions first six wk after planting drier during 2012 than 2010.
Growers Making Good Decisions IS KEY!!!!!
1. Diversified (more than just spray, spray, spray)
2. Timely herbicide applications (residuals key!)
3. Understand Palmer amaranth biology
4. More effective weed management programs
Growers Making Good Decisions IS KEY!!!!!
4. More effective weed management programs
A. Herbicides (residuals, tank mixes, etc.)
B. Hand weeding
C. Selective applicators
D. Control before, during, and after crop
E. Timeliness is still key
F. Overall objective is to eliminate seed production
Relying Too Heavily on Herbicides??
How long will Liberty last?
How long will residual of Reflex and Valor last?
2013-2015: Develop better programs reducing selection pressure on ALL herbicides
Using Heavy Rye Covers For Sustainability
Rye Cover Weedy Cover
Herbicide Resistance: Will You Survive?
If resistance is one in a billion then you
only need 918 acres to find that plant.
(historically resistance is 1 plant in population of 1-10 million…9.18 acres)
25 plants per square foot emerge = 1,089,000 plants
per acre
Questions/Comments
Heavy Rye Production System: www.farmprogress.com/heavycover