Download - Achour Amiri, Philip F. Harmon, Natalia A. Peres Winter BGA meeting, Plant City, FL, 02/20/14
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
Abou
nd
Topsin-M
Gray mold management in strawberry
Widespread Resistance in FL Strawberry Fields13.5
86.5Pristine
Sensitive Resistant
14.6
85.4
Cabrio
47.352.7
Switch (Cyprodinil)
60
40
Elevate
5
95Topsin-M
100
Switch (fludioxonil)
Botrytis outbreak on strawberry in 2012
The many faces of Botrytis on blueberry
Leaf
Shoot blight Total blossom damage
Sporulation on a blossom
Shoot tip
Green and mature fruit
Gray mold management in blueberry
Trade name Active ingredient Efficacy* Resistance Risk
Cabrio Pyraclostrobin + (curative ?) ++++
Pristine Pyraclostrobin + Boscalid ++ ++++
Fontelis** Penthiopyrad +++ +++
Elevate/Captevate Fenhexamid +++ +++
Switch Fludioxonil+cyprodinil ++++ +/+++
Captan/Captec Captan ++ (Protectant)
?
* Efficacy will depend on frequency and distribution of resistant population** Labeled for lowbush blueberry
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
Fungicide sensitivity in Botrytis in Central- FL
* The other active ingredient of Pristine
Switch
Is population shift between crops a potential source of resistance in blueberry?
?
Labeled in strawberrynot in blueberry
From the same chemical group
New, potentially effective
* Labeled for lowbush blueberry** Not registered yet
Some variability but resistance is spread across locations
a Number of isolates from each field* Both active ingredients of Switch
Location County n a Cabrio Pristine Elevate Cyprodinil* Fludioxonil*1 Polk 15 100.0 73.3 40.0 40.0 0.02 Polk 10 90.0 10.0 40.0 40.0 0.03 Citrus 15 100.0 80.0 20.0 60.0 0.04 Citrus 20 85.0 30.0 45.0 30.0 0.05 Citrus 40 85.0 52.5 52.5 42.5 0.06 Hillsborough 20 100.0 65.0 85.0 60.0 0.07 Hillsborough 10 90.0 60.0 10.0 20.0 0.08 Hillsborough 15 86.7 33.3 20.0 60.0 13.39 Hillsborough 19 64.4 42.1 21.1 31.6 0.0
10 Hillsborough 28 100.0 78.6 71.4 60.7 0.0
Resistance frequency (%)
Management at risk because of multiple resistance
MFR2 2 fungicidesMFR3 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.
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)
Is reducing number of sprays the solution?
Citrus County: Floral City
Polk County: Lake Alfred
Hillsborough County:DoverPlant CityBalm
Locations of weather stations
Reducing sprays doesn’t seem to affect control efficacy
Calendar = Weekly applicationAlert = Spray only when conditions are conducive to Botrytis
2011-2012 Strawberry season
17* 9
* Number of fungicide applications/season
168
21
11
15 10
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:
Additional management recommendations
https://edis.ifas.ufl.edu/hs380
Perspective
Conduct additional resistance monitorings across the State: Please contact us
Develop efficient rotation programs
Investigate the impact of different sources of botrytis inoculum
Acknowledgements
Participating growers Mr. Gary K. England Strawberry pathology lab team
Contact Information:
Dr. Achour AmiriGulf Coast Research and Education Center14625 CR 672Wimauma, FL, 33598
Phone: 813-633-4153Email: [email protected]
Dr. Harmon and Dr. Peres