2024
Production Updates and Seasonal Outlook for NS_ 4th Blight Line
Post_ May 3
Hi, everyone. We are officially in a Monilinia Blight
season for most of the central early/low-ground fields. From the weather
forecast, we are going to have some continuously double digital air temperatures
in the next 7-14 days which are the peak and the most susceptible timing of the
blight in wild blueberry crop fields. We will highlight Monilinia Blight management
in today’s post, but I want to remind growers to monitor crop fields and local
weather conditions very closely in the next two weeks.
Wild blueberry growers across the province can start pre-emergence
herbicide application now. In some early areas, it is getting too late. Please apply
herbicides accordingly and sooner.
-Hugh
Growing Degree
Days (GDD) Summary
This year, we are going to report GDDs from 17
stations (see Figure 2) which cover the major wild blueberry production regions
in NS. There are different ways to obtain GDDs by choosing the station you
like. To learn how to obtain GDDs, please read this blog post: http://www.novascotiawildblueberryblog.com/2023/04/2023-wild-blueberry-pest-guide-new.html.
*Please note that Earltown weather station
is out of service so we can’t report the latest GDD from this station. We will
resume once we see it back online.
Figure 1. 17 Wild Blueberry Stations for GDD updates
Here is a summary of the most up-to-date GDD from 17 weather stations in wild blueberry fields.
Figure
3. GDD Summary, May 2, 2024
Wild Blueberry Floral
Bud F2 Stage
Please see the below summary table of the percentage of
wild blueberry floral bud at the F2 stage. You can also click on this map to
check those numbers. Detailed information is also available under the Wild
Blueberry Blog- GDD&
Phenology Tracker.
Table 2. Percentage of Wild Blueberry Floral Bud F2
stage
light green (0-20% F2), dark green (20-30% F2), yellow
(30-40% F2) and red (40-100% F2)
|
Wild blueberry production regions, NS |
The average percentage of floral buds at
F2 |
|
|
|
|
South West Nova Scotia |
|
|
Queens County |
>40%- April 24 |
|
|
|
|
Hants County |
>40%- April 29 |
|
|
|
|
Cumberland County |
|
|
West Advocate |
>40%- April 29 |
|
Kikhill |
>40%- April 29 |
|
Halfway River |
>40%- April 29 |
|
|
|
|
|
|
|
|
|
|
Colchester County |
|
|
Belmont |
33% F2- May 2 |
|
Murray Siding |
45% F2- May 2 |
|
Camden |
20%
F2- May 2 |
|
|
|
|
Halifax Regional Municipality |
|
|
Middle Musquodoboit |
30-40% F2 |
|
Dean |
30-40% F2 |
|
|
|
|
Guysborough County |
5-10% F2- May 3 |
|
|
|
|
Pictou and Antigonish County |
5-10% F2- May 3 |
|
|
|
|
Cape Breton |
0% F2- May 3 |
Monilinia
Blight Management in Wild Blueberry Production
It is important to monitor plant development stages in
your fields, especially if this disease has occurred in your fields previously.
I encourage growers to go out to the fields and see how floral buds are
developing.
When looking at fruit buds do not count obviously dead
fruit buds. To do that, you can walk your fields in a “W” pattern and collect
20-30 stems randomly. From those collected stems, count the total number of
floral buds and the number of buds at the F2 stage or beyond. You can simply divide
the number of F2 buds by the total number and times 100. This would you the %
of F2. Please don’t count obviously dead floral buds.
For monilinia to infect blueberry plants, there should
be mummy berry spores, blueberry buds at a susceptible stage (F2 and above),
and an infection period of long enough wet period and temperature. Only treat
for Monillinia when blueberry buds are at least at 40% and before the next
forecasted wet period.
For products to prevent monilinia infection, please refer
to Perennia’s updated pest management guide for wild blueberry (2021): https://www.perennia.ca/wp-content/uploads/2018/03/Wild-Blueberry-WEED-INSECT-DISEASE-GUIDE-2021-WEB.pdf.
Please check with your processors or buys to see what products are allowable in
their markets.
Resources:
Monilinia Blight of Lowbush Blueberry: https://cdn.dal.ca/content/dam/dalhousie/images/sites/wild-blueberry/pdfs/Monilinia_Blight_Lowbush_Blueberry.pdf
Forecasting Mummyberry Fungus Infection: https://extension.umaine.edu/blueberries/wp-content/uploads/sites/41/2010/06/mummyberry-forecasting-handout.pdf