1. Agent In-Service Training - Effective gray mold management
Guido Schnabel
Clemson University

2. Monitoring results from 8 states, 2012
Summary
Monitoring results from 8 states, 2012 %
Switch (fludioxonil)
Rovral
Switch
Elevate
Switch (cyprodinil)
Pristine (boscalid)
Pristine (pyraclo)
Topsin M
No resistance
Moderate-high risk of resistance

3. Control (Untreated) Sensitive Resistant
Fludioxonil
Switch
Rovral
Topsin M
Cabrio
Control (Untreated)
Endura
Cyprodinil
Elevate
Sensitive
Resistant

4. Location-specific recommendation
Cyprodinil

5. Outlook for 2013
Resistance to multiple fungicides is here to stay (fitness, continued selection)
Resistance profile varies from farm to farm
Gray mold has not been a huge issue due to dry springs, but what if the weather changes?
Anti-resistance management strategies need to be implemented

6. 2013 monitoring SC location 1 Elevate Rovral Pristine Topsin M
Luna
Merivon
Fontelis
Switch
Scala
Switch
Control

7. 2013 monitoring SC location 2 GA location 1 Pristine Topsin M Pristine
Merivon
Fontelis
Switch
Scala
Switch
Elevate
Rovral
Luna
SC location 2
GA location 1

8. 2013 monitoring NC location 1 Elevate Rovral Pristine Topsin M
Switch
Merivon
Fontelis
Scala
Switch
Luna
NC location 1

9. Strategies to combat resistance
Cultural methods to keep fungus from infection
Plasticulture starts with little inoculum
Avoid leaf wetness (drip, not overhead; aeration in tunnels; plastic cover during rain?)
Frugal fertilizer use (to avoid excessive growth)
Sanitation (remove dead plant material and rotten fruit especially in early pickings)
Increase spacing between plants?

10. Strategies to combat resistance
Moderate use of site-specific fungicides
Spray them only when needed and avoid spraying ineffective materials
apply Thiram/captan prior to bloom, ROTATE others during bloom sprays (4 sprays max)
spray prior to rain events not calendar-based
get a resistance profile asap (Clemson service)

11. Best Fungicides Use broad spectrum fungicides as your primary weapons
Thiram Granuflo (4.4 lbs/acre or 2.2 lbs/100 gal; 5 applications max; 1 d REI; 3 d PHI)
Captan 80 WDG (2 to 4 lbs/acre; 30 lbs/year max; 24 h REI; 0 d PHI)
Fontelis, Endura (SDHIs)
Scala (AP)
Elevate, Captevate (HA)
Rovral (DC)
Switch (PP +AP)

12. Other Fungicides Topsin M
(no effect on gray mold and most Anthracnose)
Pristine, Merivon (2014), Luna Sensation (2014)
SDHI + QoI (good for gray mold BUT why spray and select for resistance to mildew or Anthracnose if not necessary?)
Adament, Quadris Top, Quilt Xcel
QoI + DMI (not effective for gray mold, bad choice for Anthracnose (why not spray QoI straight?)
Inspire Super
AP + DMI (good for gray mold BUT why spray for mildew if not necessary?)

13. Collecting and mailing gray mold samples for fungicide resistance profiling
Flowers
Send 20 to 40 dead strawberry flowers OR
Any symptomatic plant tissue
After incubation 22ºC-2 days

14. -Obtain cotton swabs individually wrapped
Fruit
-Obtain cotton swabs individually wrapped
-Collect 10 individual berries with FRESH gray mold lesions
-PLEASE: Do not collect from old mummies or discarded fruit on the ground
-Use a fresh cotton swab for each berry and carefully rub one side of the swab on the diseased portion of each berry without touching the fruit itself
-Return the swab to its individual package or place bulk swabs into plastic bag
Yes NO
Yes NO

15. E-mail: schnabe@clemson.edu
Mail the samples to:
Guido Schnabel
Clemson University
113 Long Hall
Clemson, SC 29634
Note: do not forget to indicate LEGIBLY the origin of the sample, your name, and so that we can send you the report electronically.