1. Managing Fire blight and
Scab with the BC Decision
Aid System
Molly Thurston, P.Ag
Claremont Ranch Organics
Presentation to BC ACARN Workshop
December 2, 2019

2. How did BC DAS come about?
• DAS is an online decision support system for Tree Fruit
Growers and Integrated Pest Management Consultants.
• DAS originated at WSU as a result of reduced extension
capacity and increasingly more complex IPM programs.
• BCDAS is collaboration between the SIR, WSU and BCTF.

3. What is the BC Decision Aid
System?
• DAS is an online decision support system for
Tree Fruit Growers and Integrated Pest
Management Consultants.
• BCDAS collects daily weather data to run pest,
disease and horticultural models.
• Provides time-sensitive pest and horticultural
information with management
recommendations

4. How does BCDAS work?
• DAS collects weather data from Growers Supply
and Environmental Canada stations to run 18
models.
• Model forecasts are based on DarkSky weather
forecast data and on 10-year temperature
averages.
• Conventional and organic management
recommendations are included.

5. What does BCDAS recommend?
• DAS can recommend product options and
timing for when to spray.
• DAS cannot recommend IF a spray is
needed in a specific orchard.
• Management decisions are made by the
grower and the pest manager, based on
observed field conditions.

6. Application of BCDAS in the Field
Case Study 1: Apple Scab

7. Apple Scab
Venturia inequalis
• Fungal disease
• 1º infection at Pink to
Petal fall during
ascospore release

8. Life Cycle of Apple
Scab
Source: https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/AppleScab.aspx

9. Setting up the Scab
Model in BCDAS
Growers using the DAS system should go into
the Apple Scab model and set the date of
green tip when it occured in your orchard.
Use Gala or McIntosh to set the date if you
have them; they are usually the first varieties
to show green tip.
As soon as apple buds reach green tip
growers have to start monitoring the weather
for apple scab.
Growers with a scab problem last year should
keep trees PROTECTED by applying scab
protection products starting at green tip.

10. By orchard
BCDAS recommendation

11. Apple Scab Management
• Protectants recommended from
Green Tip through Petal Fall in
areas with known inoculum.
• Eradicants are used in the case
of an infection period where
coverage needs to be enhanced.
• Scab coverage period in North
extends until end of ascospore
release (~mid-June).

12. How does BCDAS show a scab infection?

13. How does BCDAS show a scab infection?

14. Application of BCDAS in the Field
Case Study 2: Fire Blight in Pears

15. Fire blight
Erwinia amylovora
• Bacterial disease of
Pome Fruit
• 1º infection at
Bloom
Blossom blast on Pear

16. Fire Blight Life Cycle
Source: https://www.apsnet.org/edcenter/disandpath/prokaryote/pdlessons/Pages/FireBlight.aspx

17. Fire blight
Erwinia amylovora
• 2º infection Shoot
Blight, in season
Shoot blight on Apple

18. Case Study:
Claremont Ranch
Located: Winfield South
2.5 acres Pears, 1.5 acres
Apples
No observed fire blight in
2017 or 2017.
Adjacent to Gala Apples, two
new plantings of Ambrosia
and Honeycrisp apples.
GALA AMB
HC/AMB
Pear
Pear

19. CRO 2019 Pear
Bloom stages
April 25, 2019: Popcorn
stage
Full Bloom: April 28 – 30,
2019
FROST! April 29, -2ºC
Petal Fall: May 7, 2019
-1.7ºC

21. JUNE 1, 2019
Fire blight strikes… What happened?

22. What happened?
• Frost damage
• Pears with late bloom: May 7-14, 2019
• Apples beginning to bloom: May 10-20,
2019
• Heavy Dew throughout the spring

23. Time Machine to May 8, 2019 …

24. Time Machine to May 8, 2019 …

25. 2020 CRO Fire Blight Plan:
• Active Fire blight confirmed in
Winfield area.
• Monitor BCDAS in 2020 during Pear
and Apple bloom.
• Follow BCDAS treatment
recommendations for Biologicals
during Bloom.
• Monitor for shoot blight using BCDAS
data and field observations.
• Plan for shoot blight treatments, if
necessary.