Ellsworth/UA 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

Ellsworth/UA World Distribution of Outbreaks of B. tabaci Arizona

Ellsworth/UA State of Arizona, U.S.A. Maricopa Agricultural Center (~350 m) Yuma Agricultural Center (~50 m) Majority of cotton production in AZ

Ellsworth/UA 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.

Ellsworth/UA AZ Lint Lost Value 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. 0¢

Ellsworth/UA Pest Trends in Arizona ( ) The 1995 outbreak led to a 25-yr high in foliar insecticide use in cotton. There was a major shift in insecticide use in

Ellsworth/UA Arizona IPM Plan Introduced …due to the introduction of insect growth regulators, Bt cotton, and the Arizona IPM plan was a 25-yr low in foliar insecticide use in cotton. IGRs, Bt cotton, & AZ IPM Plan introduced

Ellsworth/UA Whitefly IPM… …depends on 3 basic keys 1 2 3

Ellsworth/UA Avoidance 1 …all practices that serve to prevent or maintain pests below economic levels.

Ellsworth/UA Crop Management …some factors lead to increased SWF numbers, such as water-stress, excess N, or hairy-leafed cultivars

Ellsworth/UA 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

Ellsworth/UA Area-Wide Impact …is needed for this mobile & polyphagous pest & includes elements of cooperation, source reduction & attention to SWF movement...

Ellsworth/UA Areawide Impact …also depends on stable systems of management to be in place for all sensitive crops in order to reduce area-wide pressure.

Ellsworth/UA When SWF are damaging …we depend on the top two levels of the pyramid

Ellsworth/UA Sampling …sits atop the pyramid & serves all layers of management.

Ellsworth/UA 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

Ellsworth/UA Field Sampling for Nymphs Count adults first 5th leaf Locate between main veins “Quarter- sized” disk Large nymphs Presence / Absence count on 30 leaves Determine % infested

Ellsworth/UA Action Thresholds …with sampling, can be used to precisely time sprays with IGRs (Stage I) & other insecticides (Stage II & III).

Ellsworth/UA 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

Ellsworth/UA Selective & Effective Chemistry …the insect growth regulators sit at the center of our pyramid.

Ellsworth/UA Egg Crawler 2nd 3rd 4th, “pupa” Adult Knack ® ® Applaud ™ ™ Major Points of Insect Growth Regulation buprofezin pyriproxyfen

Ellsworth/UA IGRs & Natural Enemy Conservation …demonstrate the interaction between levels of the pyramid to produce “bioresidual”...

Ellsworth/UA 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 biologicalbiologicalbiologicalbiological insecticeinsecticeinsecticeinsectice

Ellsworth/UA Bioresidual via natural mortality extends the effectiveness of IGRs, while conventional sprays kill natural enemies & require repeated sprays. … commercial-scale studies are shown for two years here... One IGR spray lasts ONLY 14 days chemically IGRs v. Conventional Chemistry … 3 conventional sprays, or just 1 IGR spray needed in chemical residual … 4 conventional sprays vs. just 1 IGR spray in UTC threshold bioresidual bioresidual 7–8 weeks ~6 weeks

Ellsworth/UA 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) don’t waste the bioresidual 3)Delay the use of follow-up sprays for 14–21 days i.e., at least 1 generation of whiteflies

Ellsworth/UA Resistance Management …is a shared responsibility to ensure efficacy of our valuable chemistry. All chemistry falls into 1 of 3 stages...

Ellsworth/UA 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

Ellsworth/UA 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”.

Ellsworth/UA 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

Ellsworth/UA Information All University of Arizona crop production & crop protection information is available on our web site, Arizona Crop Information Site (ACIS), at ACISACIS