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

Scope of IPM Ehler [Pest Manag. Sci. 62: (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….

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………

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.

For today’s 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 bug:WFT ratios UV mulch Product rotation Use selective insecticides Do not overuse chemical control Good crop sanitation

Palm Beach, FL Situation 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.

Bioassays of Spinosad toxicity to WFT collected from same farm, Palm Beach Co., Florida (J. Funderburk UFL, A.W. Weiss, DAS) End of 2006 crop season Spinosad sprayed twice No Spinosad Sprayed to This Date Populations shift from >95% western flower thrips in May06 to >95% Florida flower thrips in Nov-Dec06 to >95% western flower thrips in Jan-May07 Percent WFT Mortality WFT Managed based on thresholds

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 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.

Effect of IPM vs No IPM – Bioassay of Spinetoram toxicity to WFT collected on peppers, (J. Funderburk, et al, Mar 2008) 8 μg/ml 1000 μg/ml IPM Grower Non-IPM Grower Percent WFT Mortality Spinetoram spray tank conc. = 4-16 μg/mL

Effect of IPM vs No IPM – Bioassay of Spinetoram toxicity to WFT collected on strawberries, (J. Funderburk, et al, Mar-Apr 08) 1.6 μg/ml 1000 μg/ml IPM Grower Non-IPM Growers Percent WFT Mortality Spinetoram spray tank conc. = 4-16 μg/mL

IRM (Insect Resistance Management) is a part of IPM When might other chemistries be used?

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.

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) ® Trademark of Dow AgroSciences LLC

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

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.