Growing Degree
Days (GDD) Summary and 2024 Spring Plant Development Prediction
This year, we are going to report GDDs from 17
stations (see Figure 1) 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.
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
2. GDD Summary, April 18, 2024
Plant Development:
I want to share a graph
from Jeff Franklin (AAFC Plant Physiology) who has been contributing very good weather
information from Kentville for wild blueberry extension publications.
Figure 3: Heating degree day accumulations for plant (above 5°C) and insect
(above 10°C) development from March 1 to April 17 for the past 17 seasons.
Provided by Jeff Franklin (AAFC Plant Physiology).
The degree day
accumulations beginning on March 1 are ahead of the 5- and 10-year averages
(Figure 3). This season is arriving sooner
compared to last year. We experienced above-average temperatures in March in NS
and some additional heat was likely also accumulated prior to March 1 due to
above-average temperatures, meaning that even though this year looks equivalent
to the year 2022 we are actually a few days ahead.
Based on conversations with growers, field observations and a progressive calculation I took, here are my thoughts about plant emergence in sprout fields and who should start putting pre-emergence herbicides on next week:
Table 1. The comparison of GDD accumulation from different start dates
|
Stations |
GDD
Summary (April 1- April 18) |
GDD Summary (March 1- April 18) |
|
West
Caledonia (NSW026) |
109 |
195 |
|
Upper
Rawdon (NSW099) |
76 |
141 |
|
West
Advocate (NSW 091) |
87 |
169 |
|
Halfway
River (NSW039) |
86 |
163 |
|
Kirkhill
(NSW082) |
79 |
147 |
|
Oxford
(NSW005) |
81 |
160 |
|
Westchester
Station (NSW094) |
77 |
146 |
|
Camden
(NSW090) |
72 |
138 |
|
Murray
Siding (NSW002) |
82 |
168 |
|
Dean
(NSW069) |
72 |
141 |
|
FiveIslands(NSW062) |
67 |
114 |
|
Earltown
(NSW089) |
64 |
118 |
|
Sunny
Brae (NSW058) |
63 |
123 |
|
College
Grant (NSW040) |
62 |
121 |
|
NewFrance(NSW075) |
55 |
113 |
|
Skye
Mountain (NSW028) |
47 |
93 |
|
Keppoch
(NSW029) |
44 |
96 |
|
Average |
72 |
138 |
Sprout fields:
If you are in areas with yellow highlighted colour, you are ready to apply
pre-emergence herbicides in the next 7-10 days. The weather forecasts for those
areas also look at around 10-14 degrees C daily high temperatures. Other areas
are still a bit early but only a few days difference compared to those early
areas.
Crop fields:
Only growers who own fields in the south shore area should worry about
monilinia blight management this and next week. We have reports from some
fields/regions, please take a look at Table 2.
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 |
30-40% F2 |
|
|
|
|
Hants County |
10% F2 |
|
|
|
|
Cumberland County |
|
|
West Advocate |
20% F2 |
|
Kikhill |
10-15% F2 |
|
Halfway River |
30-40% F2 |
|
|
|
|
Colchester County |
|
|
Belmont |
3% F2 |
|
Murray Siding |
10% F2 |
|
Camden |
7% F2 |
|
|
|
|
|
|
|
Guysborough County |
0% F2 |
|
|
|
|
Pictou and Antigonish County |
0% F2 |
|
|
|
|
Cape Breton |
0% F2 |