Transcript vargas - ucbiotech.org

GM CROPS IN CALIFORNIA
Large Acreage: Cotton
RON VARGAS, FARM ADVISOR
UNIVERSITY OF CALIFORNIA
COOPERATIVE EXTENSION
Madera/Merced Counties
Progression of GM Cotton in San Joaquin
Valley
1996
1997
Small UCCE Research Studies
Small experimental acreage
600 RR
< 100 BXN
1998 1st commercial plantings
1,200 RR
1,000 BXN
1999 Acreage increased dramatically when SJV “One
Quality” law changed
85,000 RR
14,000 BXN
2000 227,000 RR 68,000 BXN
2001 235,000 RR 70,000 BXN
2002 173,000 RR 24,000 BXN
(42,000 RR + Bt)
(some staked gene RR/ Bt)
(3,130 RR/ Bt) (351 Bt)
Transgenic Herbicide Tolerant Cotton
• Allowed grower to effectively control most
annual and perennial weeds
• Reduce or eliminate hand hoeing and
cultivation
• Cost Savings – range from $25 - $120/acre
• Explore alternative production systems
– Conservation/reduced tillage
– Ultra narrow row
Limitations
• BXN – broadleaf control only
– tank mix with grass herbicides
• RR – small window of application, heavy penalty
in yield, and some extent quality, for off-label
applications
• Difficult to control weeds-nutsedge, field
bindweed, annual morningglory
Integrated Weed Management System
• These systems can be very useful as another
weed control option to supplement existing
weed control programs based upon the use
of pre-plant, selective over-the-top and
layby herbicides.
Decision to Use Transgenic Herbicide
Tolerant Cottons
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Weed species present (annuals vs. perennials)
Density and extent of weed population
Is weed pressure enough to impact yield?
Is hand weeding or cultivation eliminated?
Cost of alternative herbicides
Cost of technology fee
Are there well suited transgenic varieties with
favorable agronomic characteristics (yield and
quality)?
Weed Resistance Concerns
• If weed control programs are developed which
solely rely on one type of herbicide there is a high
probability of developing resistant weed species
and/or weed shifts.
• Example:
– annual ryegrass, marestail
– Growers have reported poor control of barnyardgrass
and lambsquater
Resistance Management
• A well balanced long-term weed
management approach must incorporate
resistance management strategies:
– Crop rotation
– Herbicide rotation
– Control of weed escapes by hand or tillage
Future Developments
• Enhanced Roundup Ready varieties – wider
window of application
• Liberty link cotton varieties
Bt and Bollgard Varieties
• Especially suited for pink bollworm and
budworm – not problems in California
• Fewer total pesticide sprays required since
fewer worms
• Insect resistance and refuge issues
Concerns
• How to segregate transgenic from
conventional varieties (starlink corn)
• Transgenic cotton seed as animal feed
(studies to date of protein and amino acids
are equivalent to conventional varieties
• Development of “super weed” – genetic
shifts in weeds resulting in potential to
increase weed problems
Concerns contd.
• Impact on non-target organisms (beneficial
insects and butterflies
• Changes in dominant insect pest: with
changes in spray programs with Bt cotton –
do pests that once were secondary become
more damaging with reduced pesticide
applications?
Other Large Acreage GM Crops
• Corn, 40-50,000 Acres in 2002
• Rice
• Alfalfa