Integrated Management of Whiteflies in Arizona

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Integrated Management of Whiteflies in Arizona

• Peter C. Ellsworth, Ph.D.
• IPM Specialist, University of Arizona
• Maricopa, AZ, USA
• Steve Naranjo, Ph.D.
• Research Scientist, USDA-ARS, WCRL
• Phoenix, AZ, USA

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World Distribution of Outbreaks of B. tabaci
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State of Arizona, U.S.A.
Maricopa Agricultural Center (350 m)
Majority of cotton production in AZ
Yuma Agricultural Center (50 m)
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Impact of SWF on Arizona

• Whiteflies (biotype B) invaded Arizona in the
  early 1990s.
• Losses to the agricultural industry were
  catastrophic.
• Honeydew excreted by SWF caused sticky cotton
  that could not be sold at a premium price after
  outbreaks in 1992 1995.

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AZ Lint Lost Value
0

• In the late 1980s, AZ enjoyed a premium for its
  cotton lint relative to New York Futures.
• The 1992 1995 outbreaks led to depressed prices
  for AZ lint, a loss that we continue to endure in
  spite of clean cotton.

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Pest Trends in Arizona (1990-2000)

• The 1995 outbreak led to a 25-yr high in foliar
  insecticide use in cotton.
• There was a major shift in insecticide use in
  1996...

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Arizona IPM Plan Introduced

• due to the introduction of insect growth
  regulators, Bt cotton, and the Arizona IPM plan.
• 1999 was a 25-yr low in foliar insecticide use in
  cotton.

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Whitefly IPM
depends on 3 basic keys
3
2
1
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Avoidance
all practices that serve to prevent or maintain
pests below economic levels.
1
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Crop Management
some factors lead to increased SWF numbers, such
as water-stress, excess N, or hairy-leafed
cultivars
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Exploitation of Pest Biology Ecology
knowing your enemy will help guide prevention
efforts, such as specific information on how SWFs
are dying the role of natural enemies
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Area-Wide Impact
is needed for this mobile polyphagous pest
includes elements of cooperation, source
reduction attention to SWF movement...
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Areawide Impact
also depends on stable systems of management to
be in place for all sensitive crops in order to
reduce area-wide pressure.
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When SWF are damaging...
we depend on the top two levels of the pyramid
3
2
1
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Sampling
sits atop the pyramid serves all layers of
management.
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Sampling ( 7 min. / field)

• Locate 5th leaf (below terminal)
• Score as infested with adults when
• 3 or more adults present
• Examine quarter-sized leaf disk
• Score as infested with nymph when
• 1 or more LARGE nymphs present
• Tally up 30 leaves 30 leaf disks

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Field Sampling for Nymphs
Determine infested
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Action Thresholds
with sampling, can be used to precisely time
sprays with IGRs (Stage I) other insecticides
(Stage II III).
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Whitefly Thresholds

• Timing of IGRs (Stage I)
• 40 of leaves infested with 3 or more adults
• 40 of disks infested with 1 or more large
  nymphs
• Timing Stage II III conventional sprays
• 57 of leaves infested with 3 or more adults

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Selective Effective Chemistry
the insect growth regulators sit at the center
of our pyramid.
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Major Points of Insect Growth Regulation
pyriproxyfen
Knack

Knack

Adult
4th,

Egg
pupa
Crawler
2nd
3rd
Applaud

Applaud

buprofezin
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IGRs Natural Enemy Conservation
demonstrate the interaction between levels of
the pyramid to produce bioresidual...
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What is Bioresidual?

• Overall killing power of an insect control
  technology including the direct effects of the
  technology (i.e., chemical residual) PLUS the
  associated natural biological mortality.
• Ellsworth Martinez-Carrillo, 2001

biological
insectice
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IGRs v. Conventional Chemistry
Bioresidual via natural mortality extends the
effectiveness of IGRs, while conventional sprays
kill natural enemies require repeated sprays.
4 conventional sprays vs. just 1 IGR spray in
1997.
commercial-scale studies are shown for two
years here...
One IGR spray lasts ONLY 14 days chemically
3 conventional sprays, or just 1 IGR spray
needed in 1999.
1999
1997
78 weeks
bioresidual
bioresidual
6 weeks
threshold
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Recommended Strategy

• 1) Use IGRs first (1 use each only)
• 40 infested leaves AND
• 40 infested disks
• 2) Use IGRs without mixing with other chemicals
  (if possible)
• dont waste the bioresidual
• 3) Delay the use of follow-up sprays for 1421
  days
• i.e., at least 1 generation of whiteflies

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Resistance Management
is a shared responsibility to ensure efficacy of
our valuable chemistry. All chemistry falls into
1 of 3 stages...
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Three Stage Strategy

• Stage I Use IGR of choice when counts exceed
  threshold
• Follow-up with alternate IGR, if needed
• Use each no more than once
• Stage II Use Stage II (non-pyrethroid) materials
  at least once before Stage III materials
• Do not use foliar neonicotinoids in multi-crop
  communities or more than twice in cotton areas
• Stage III Reserve use of pyrethroid mixtures
  until end of season, and no more than twice

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Conclusions (1)

• With the adoption of the AZ IPM plan, SWF sprays
  have been reduced by 71 to around 1 spray per
  season, and growers have saved over 100 million
  in control costs and yield savings in the last 5
  years.
• The AZ IPM plan depends on multiple elements of
  Sampling Effective Chemical Use built on a
  foundation of Avoidance.

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Conclusions (2)

• Six years of success have been based on
• research-based guidelines for sampling
  thresholds,
• access to powerful selective IGRs with proven
  guidelines for their use,
• the extended suppressive interval, known as
  bioresidual, which maximizes natural mortality
  factors of the SWF creates area-wide benefits,
  and
• an organized comprehensive educational campaign

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Information
ACIS

• All University of Arizona crop production crop
  protection information is available on our web
  site,
• Arizona Crop Information Site (ACIS), at
• http//ag.arizona.edu/crops