Transcript Stewardship/Management of Transgenic Products

Stewardship/Management of
Transgenic Products
Micheal D. K. Owen
Iowa State University
Ames, IA 50011 USA
[email protected]
www.weeds.iastate.edu
Introduction
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Stewardship reflects management
decisions that will enhance and preserve a
particular crop trait and are economically
rewarding
Some traits impart selection pressure
upon the pest complex for which they are
designed (i.e. BT)
Traits for herbicide resistance in crops are
“benign” and do not exert selection
pressure – the herbicide exerts the
selection pressure
Introduction
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The “stewardship” efforts initiated by
the Weed Science group and
supported by the Iowa Grain Quality
Initiative represent two areas:
• Evaluation and monitoring of weeds with
variable responses to glyphosate
• Development of weed management
strategies for specific output traits or
specialty traits
Glyphosate stewardship
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Clean fields do not necessarily equate to good
weed management
• The objective of weed management is to
protect crop yield potential
Diversified weed management tactics provide
significant benefits to glyphosate-based systems
• Residual herbicides applied EPP or PRE are
important components of a weed management
program
• Mechanical weed control tactics should be
included
Timely application of tactics is critical for all weed
management programs
Stewardship and Grower Attitudes
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Considerable effort in providing
information about the evolution of
herbicide resistance
These efforts have been marginally
effective (e.g. ALS resistance)
66% of Indiana growers expressed only a
low to moderate concern about glyphosate
resistance
Only 38% recognized the role of repeat
MOAs on selection pressure
Adoption of glyphosate-resistant crops
continues to rise
The Glyphosate Decade
2006: Horseweed in NE
1998:
2000:
Rigid ryegrass in CA
Horseweed
in DE, MD, NJ
2001:
Horseweed
in TN, KY
2002:
Horseweed
in IN, OH
2002: “Variably tolerant”
waterhemp in IA,
IL, MO
2003: Horseweed in AR, MS, NC
2004:
2004:
Common ragweed in MO
Italian ryegrass in OR
2005:
2005:
Horseweed in CA
Palmer pigweed in GA and TN
Source: University & USDA reports
2005:
Palmer pigweed
suspected in NC
2005: Common waterhemp in MO
Weeds to watch in Iowa
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Common lambsquarters
Giant ragweed
Common waterhemp
Asiatic dayflower
Marestail
Others?
Even at low population (10 plants/m2) Asiatic dayflower
reduces soybean yield (Mishra et al 2002)
Figure 2. Percentage of Asiatic dayflower control
Control
35
6 oz/acre
30
% control
12 oz/acre
25
24 oz/acre
20
48 oz/acre
15
96 oz/acre
10
5
0
2-4
4-8
8-10
10-12
growth stage (number of leaves)
12-16
Specialty grains/high value crops
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Several field experiments have been
conducted on inbreds, cultivars, and
output trait crops
Experiments focus on evaluating the
potential for existing and new herbicides
to manage weeds in these crops
Particular attention is given to the relative
tolerance of the crops to the herbicides
Past efforts had included considerable
experimentation with popcorn varieties
2006 efforts
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Experiments with 8 low lin soybean
varieties
Experiments with 3 white corn
varieties, 1 high oil and 1 waxy
variety
Experiments on 7 sensitive and very
sensitive inbreds
2006 efforts
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Registered and experimental
herbicides were included in the
experiments
Application timing, herbicide
combinations and rates were
included
Results available at
www.weeds.iastate.edu
Questions?