The Role and Use of Insecticides and the Need for IPM in the Successful Management of Western Flower Thrips

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The Role and Use of Insecticides and the Need for
IPM in the Successful Management of Western
Flower Thrips

• Anthony Weiss, Dow AgroSciences
• James Dripps, Dow AgroSciences
• Joseph Funderburk, University of Florida
• August 29, 2008

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Scope of IPM

• Ehler Pest Manag. Sci. 62787-789 (2006),
  states that for the IPM practitioner, IPM
  encompasses
• Simultaneous management of multiple pests.
• Regular monitoring of pests and their natural
  enemies and antagonists.
• Use of economic or treatment thresholds when
  applying pesticides.
• Integrated use of multiple, suppressive tactics.
• Furthermore.

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Scope of IPM

• Integration of IPM tactics may be
• Vertical - effects of multiple tactics are
  compatible within a class of pests (insects or
  pathogens or weeds), or
• Horizontal - effects of multiple tactics are
  compatible across classes of pests (insects and
  pathogens and weeds)
• As a group, we must first collectively decide the
  scope of what we need to accomplish
• Integration of tactics for a single insect pest
  or multiple insect pests within a crop system?
• Integration of tactics for just insect pests or
  all pests within a crop system?
• There are many permutations

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Scope of IPM

• With a common scope established, we can better
• Implement the use of insecticides
• Focus on the sustainability of IPM programs.
• We propose
• Full horizontal integration of IPM tactics is the
  ideal situation to strive for.
• But in practice, achieving vertical integration
  of IPM tactics for a single pest is difficult.

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For todays discussion

• We will focus on the role of insecticides and the
  need for integrated pest management (IPM) tactics
  for managing western flower thrips (WFT),
  Frankliniella occidentalis, in Florida tomatoes,
  peppers, and strawberries. Plus whitefly and
  pepper weevil
• Specific IPM Practices for WFT
• Why is IPM important?

• Thrips species identification
• Use spray thresholds
• Pirate bug (Orius) refugia
• Pirate bugWFT ratios
• UV mulch

• Product rotation
• Use selective insecticides
• Do not overuse chemical control
• Good crop sanitation

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Palm Beach, FL Situation - 2006

• Discovery of WFT tolerance to spinosad began as a
  product performance inquiry.
• Spray timing, use rate, tank pH, product quality,
  etc. were eliminated as possible factors.
• Thrips samples were sent to J. Funderburk for
  bioassay, which identified that tolerance had
  developed.
• DAS, UFL, and Glades Crop Care worked together to
  address the situation with the grower.
• Initial perception of the grower was that all/any
  thrips threaten the quality of his high-value
  colored pepper crop.
• In fall 2006 and spring 2007, consulted with the
  grower to identify thrips species present and
  make recommendations on IPM tactics to follow and
  when to treat.
• The result was acceptable WFT management for a
  full season.

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Bioassays of Spinosad toxicity to WFT collected
from same farm, Palm Beach Co., Florida (J.
Funderburk UFL, A.W. Weiss, DAS)
Percent WFT Mortality
End of 2006 crop season
Spinosad sprayed twice
No Spinosad Sprayed to This Date
WFT Managed based on thresholds
Populations shift from gt95 western flower thrips
in May06 to gt95 Florida flower thrips in
Nov-Dec06 to gt95 western flower thrips in
Jan-May07
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Palm Beach, FL Situation 2007 to 2008

• May 2007 Held meetings in Palm Beach and
  Homestead to make growers aware of WFT resistance
  in area, emphasize IPM practices, and call to
  action to preserve product.
• Oct 2007 Emphasized the above topics in a second
  meeting in Palm Beach.
• Oct 2007 - Jan 2008 Visited growers to continue
  education and monitor WFT population dynamics and
  susceptibility
• Jan 2008 Trained consultant and county personnel
  on how to identify thrips species.
• Today Some growers in SE FL have adopted some
  IPM measures.
• Growers who have adopted IPM tactics maintained
  WFT susceptibility to spinosyns and achieved
  better WFT control than those who have not.

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Effect of IPM vs No IPM Bioassay of Spinetoram
toxicity to WFT collected on peppers, (J.
Funderburk, et al, Mar 2008)
Spinetoram spray tank conc. 4-16 µg/mL
1000 µg/ml
Percent WFT Mortality
8 µg/ml
Non-IPM Grower
IPM Grower
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Effect of IPM vs No IPM Bioassay of Spinetoram
toxicity to WFT collected on strawberries, (J.
Funderburk, et al, Mar-Apr 08)
Spinetoram spray tank conc. 4-16 µg/mL
Percent WFT Mortality
1.6 µg/ml
1000 µg/ml
IPM Grower
Non-IPM Growers
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IRM (Insect Resistance Management) is a part of
IPM

• When might other chemistries be used?

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Components with the greatest impact on resistance
management

• Rotate to other classes of chemistry.
• Use recommended rates.
• Do not exceed label restrictions.
• Avoid sequential treatments
• Within a single planting
• Across sequential crops/plantings.

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Use of selective vs. non-selective insecticides
for WFT management in fruiting vegetables

• We are committed to the use of pirate bugs to
  their fullest extent to reduce the need for
  insecticide applications
• We are committed to use selective insecticides to
  fullest extent possible without risk of
  resistance
• But we cannot use selective insecticides
  continuously without risk of resistance
• If pirate bugs are not present or if white fly or
  pepper weevil appear, it may be necessary to use
  other products that are not selective.
• In order not to over use selective insecticides
  it may be necessary to use non-selective
  insecticides but do so in a way that minimizes
  the impact on beneficials (ie pirate bugs)

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Use of selective vs. non-selective insecticides
for WFT management in strawberries

• We are committed to the use of beneficial insects
  to their fullest extent to reduce the need for
  insecticide applications
• We are committed to use selective insecticides to
  fullest extent possible without risk of
  resistance
• But we cannot use selective insecticides
  continuously without risk of resistance
• If thrips populations continue to exceed
  thresholds, it may be necessary to use other
  products that are not selective
• In order not to over use selective insecticides
  it may be necessary to use non-selective
  insecticides but do so in a way that minimizes
  the impact on beneficials

Trademark of Dow AgroSciences LLC
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Conclusion

• Our IPM target is full integration (horizontal)
  across pests
• We recognize this is difficult but we must strive
  for this
• IPM and IRM play an important role in the
  successful management of western flower thrips
• The benefits to growers who used IPM were fewer,
  more effective sprays and less selection for
  resistance.
• Key components of IRM are
• Rotate to other classes of chemistry,
• use recommended rates,
• do not exceed label restrictions,
• avoid sequential treatments.
• If there is a need to consider non selective
  insecticides for WFT, but we must be careful in
  doing so.