1. Achour Amiri, Philip F. Harmon, Natalia A. Peres Winter BGA meeting, Plant City, FL, 02/20/14 Early signs of widespread fungicide resistance in Botrytis across blueberry fields in central Florida

2. Abound Topsin-M Gray mold management in strawberry

3. Widespread Resistance in FL Strawberry Fields

4. Botrytis outbreak on strawberry in 2012

5. The many faces of Botrytis on blueberry Leaf Shoot blight Total blossom damage Sporulation on a blossom Shoot tip Green and mature fruit

6. Gray mold management in blueberry Trade nameActive ingredientEfficacy*Resistance Risk CabrioPyraclostrobin+ (curative ?)++++ PristinePyraclostrobin + Boscalid++++++ Fontelis**Penthiopyrad+++ Elevate/CaptevateFenhexamid+++ SwitchFludioxonil+cyprodinil+++++/+++ Captan/CaptecCaptan++ (Protectant) ? * Efficacy will depend on frequency and distribution of resistant population ** Labeled for lowbush blueberry

7. Survey of fungicide sensitivity in Botrytis in Central- FL  10 locations surveyed in 2013 (March-May)  2 in Polk County  3 in Citrus County  5 in Hillsborough County  Total number of isolates: 192  Sensitivity to 9 fungicides from different chemical groups

8. Fungicide sensitivity in Botrytis in Central- FL * The other active ingredient of Pristine Switch

9. Is population shift between crops a potential source of resistance in blueberry? ? Labeled in strawberry not in blueberry From the same chemical group New, potentially effective * Labeled for lowbush blueberry ** Not registered yet

10. Some variability but resistance is spread across locations a Number of isolates from each field * Both active ingredients of Switch

11. Management at risk because of multiple resistance MFR2 2 fungicides MFR3 3 “ MFR4 4 “ MFR5 5 “ MFR6 6 “ MFR7 7 “ Phenotype Resistant to MFR = The same isolate may be resistant to 2, 3, 4 or more fungicides, simultaneously.

12. Best management practices  Spray when the plant is most susceptible: Flowering and  When weather conditions are conducive: Temperature ( ~68°F) and wetness (10 to 14h)

13. Is reducing number of sprays the solution? Citrus County: Floral City Polk County: Lake Alfred Hillsborough County: Dover Plant City Balm Locations of weather stations

14. Reducing sprays doesn’t seem to affect control efficacy Calendar = Weekly application Alert = Spray only when conditions are conducive to Botrytis 2011-2012 Strawberry season 17* 9 * Number of fungicide applications/season 16 8 21 11 15 10

15. Spray at appropriate timing and growth stage  Low Botrytis Risk: spray Captan  Moderate Botrytis risk: spray Elevate, Pristine, Fontelis (lowbush)  High Botrytis risk: spray Switch Preferably within the 24 hours following the alert http://www.agroclimate.org/tools/strawberry/ Monitoring weather conditions, sign up, alerts:

16. Additional management recommendations https://edis.ifas.ufl.edu/hs380

17. Perspective  Conduct additional resistance monitorings across the State: Please contact us  Develop efficient rotation programs  Investigate the impact of different sources of botrytis inoculum

18. Acknowledgements  Participating growers  Mr. Gary K. England  Strawberry pathology lab team Contact Information: Dr. Achour Amiri Gulf Coast Research and Education Center 14625 CR 672 Wimauma, FL, 33598 Phone: 813-633-4153 Email: aamiri@ufl.eduaamiri@ufl.edu Dr. Harmon and Dr. Peres