crop management seminar introduction weed …...2017/03/17 · crop management seminar introduction...
TRANSCRIPT
Cotton IncorporatedCotton Incorporated Crop Management Seminar
Introduction to the SessionIntroduction to the Session
Weed Management Robert Nichols
Cotton Incorporated
Predominant IssuesPredominant Issues Glyphosate Resistanceyp
• Management of Glyphosate-Resistant Palmer AmaranthPalmer Amaranth
• Management of Glyphosate-Resistant RyegrassRyegrass
• Containing Glyphosate-Resistant JohnsongrassJohnsongrass
• Future Cotton and Soybean Weed Management
Definition: Weed ResistanceWeed Resistance
“Inherited ability of a weed population y p pto survive and reproduce after exposure to an herbicide dose (rate) p ( )that would control an unselected population”
--- Weed Science Society of America
90 ACCase InhibitorsALS Inhibitors
70
80
cies
.
TriazinesBypyridiliumsSynthetic Auxins
50
60
tant
Spe
c Glycines
30
40
r of R
esis
10
20
30
Num
ber
0
10
0 5 10 15 20 25 30 35 40 45 50 55 600 5 10 15 20 25 30 35 40 45 50 55 60
Years of Usage
Acetolactate Synthase Resistant Palmer Amaranth
99*
93
99 02
9698 93
0094
9293
9495
9700
92
9402
* Year of 1st
reportp
Glyphosate-Resistant Crop Acres ( illi )(millions)
120
80
100
60
80
illio
n A
cres
40
M
0
20
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 20061996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Cotton Corn Soybean
Percent of Glyphosate-Resistant Cotton Cultivars
9799
989910059
100
66
99
989899 98
9883
9775
99
USDA, AMS. 2006.
Total Acres Exposed to Herbicide Modes of Action f C S b C ttfor Corn, Soybean, Cotton
140,000
60,000
80,000
100,000
120,000
Acr
es x
103
0
20,000
40,000
19901992
19941996
A
19961998
20002002
20042006
DNA Acetanilides Glyphosate TriazinesDNA Acetanilides Glyphosate Triazines
Number of Glyphosate-Resistant Species
20
14
16
18
8
10
12
Cou
nt
4
6
8
0
2
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
YearsYears
Palmer Amaranth(Amaranthus palmeri)(Amaranthus palmeri)
A dioecious annual weed,
growinggrowing 4-8 feet tall,producing
up to 500,000seed per year
Impacts of Glyphosate-ResistantImpacts of Glyphosate Resistant Palmer Amaranth
• Increased complexity and costs of weed management in cotton andweed management in cotton and soybeanC• Compromising conservation tillage
• May precipitate a cascade of resistance in post emergence broad-leaf herbicides
Glyphosate-Resistant Palmer AmaranthGlyphosate Resistant Palmer AmaranthEconomic Threat to Soybeans
If ALS d l h t i d PPOIf ALS and glyphosate are compromised, PPO herbicides are the only post emergence option except glufosinatep g
Economic Threat to Cotton If ALS herbicides and glyphosate are compromised; PPO herbicides are not an over-the-top option, there are no selective post emergence options for cotton except glufosinate