Hello, everyone
As we approach the end of June, this year’s blueberry
pollination season will be wrapped up soon. Most of the time, the weather is favourable
in the province during this year’s pollination period. The dry and warm weather
brought some ideal flying days for pollinators, and pollination activities were
active this season in blueberry fields. The dry weather during the bloom period
also reduced the risk of Botrytis infection for this year, compared with higher
Botrytis infections in the last couple of bloom seasons. As soon as green
berries are formed, the crop fields are no longer required to undergo blight
management; therefore, this would be the last blight update for the season. We
will continue to provide updates on blueberry management in this blog.
In the last blight line post, I want to update the
following items:
1. 2025
wild blueberry blight management summary
2. Field
Management Recommendations
3. GDD
updates (April 1- June 20)
1.
2025 wild blueberry blight management summary
This year, the wild blueberry crop development in Nova
Scotia is back to the regular schedule. In the early spring, a few warm periods
pushed fruit buds to develop and break earlier, but we also had cool and wet
weather that slowed down bud development. This year’s fruit bud development, as
well as blooms, progressed steadily.
Monilina Blight (Mummy Berry)
During the bud development period, especially after F2, crop
development slowed due to cool and wet weather. Most crop fields experienced a
longer bud period this year, which increased the crop’s susceptibility to
blight infections. We also encountered a couple of infection periods that posed
a high risk of blight infections to crop fields.
Based on field scouting and the growers’ feedback, we had
higher Monilinia Blight infections in the current season. In unsprayed fields, higher
infections and more obvious blight symptoms are expected.
With this year’s conditions, we also observed more secondary
infections on blooms from Monilinia Blight, which is a concern as those blossoms
might develop into mummy berries and become infection sources (Figure 1).
Figure 1. Monilinia Blight (Mummy
Berry) infection on blossoms (Dr. Paul Hildebrand)
Botrytis Blossom Blight
As mentioned in the introduction, we didn’t have a wet bloom
season, which helped reduce the risk of infection from Botrytis blight. This
year, we didn’t have the same botrytis infection scales as in the last few
seasons, meaning there will be fewer infected blossoms and more healthy flowers
for pollinators. Ultimately, we can expect to see more green berries if they
get pollinated.
2.
Field Management Recommendations
Crop Fields
During berry development, we need to reduce crop field
activities, particularly events requiring larger machines or risky products. We
recommend that growers only perform necessary and mandatory activities, and
here are some recommendations:
a.
Assessing pollination efficiency and fruit set. Once
bees are moved and green berries are formed, checking fruit set and
understanding your fields’ pollination efficiency is ideal.
b.
Spot weed management. It is an ideal time to
spot control weed patches by cutting or spot spraying. This recorded
presentation by Dr. Scott White could give you tips on that topic. https://www.youtube.com/watch?v=aK5AXDUqBKc&t=1025s.
c.
Insect monitoring and spraying.
We are also in insect season and must monitor and control
two insects: spotted wing drosophila (SWD) and Blueberry Maggot.
On July 9, we will have a guest speaker, Dr. Rachel Rix, join
the virtual grower meeting to refresh us on SWD and Blueberry Maggot, including
their life cycles, identification, and trapping techniques. The virtual meeting
starts at 8:30 am on July 9. Here is the registration link: https://perennia.zoom.us/meeting/register/jw0VYQHbRfaKWeaf3tWFUQ#/registration.
https://www.perennia.ca/eventer/wild-blueberries-virtual-grower-meetings-2025/edate/2025-04-09/
Sprout Fields
Sprout fields are around 80-90% plant emergence. Some early new
sprouts reached the tip-dieback stage, when blueberry plants start to produce
fruit buds for the following year. Over the next few weeks, growers can focus
more on sprout fields, especially the following areas:
a.
Fertilization. If you are using granular
fertilizer, it is recommended that you fertilize your sprout fields within the
next week or two before the weather gets too hot.
b.
Post-emergence broadleaf and grass weeds. After
Chikra, Ignite, Spartan or other pre-emergence herbicides, some fields might
require a second broadcast spray, using Callisto and/or Venture L. The ideal
time to apply those chemicals is also in the next two weeks or before the air temperatures
exceed 28 °C.
c.
Spot cutting and spraying weed control. Spot
weed control could effectively and economically manage late-growing weeds, such
as goldenrods, spreading dogbane, vetch, late grasses, etc. Again, I encourage
you to watch Dr. White’s presentation to learn how to control spot weeds
effectively. https://www.youtube.com/watch?v=aK5AXDUqBKc&t=1025s.
d.
Wild blueberry leaf disease management. This is crucial
to ensure that sprout blueberry plants are healthy and productive to form next
year’s fruit buds. It is still early, so we will discuss this topic more next
month.
3.
GDD updates (April 1- June 20)
We have selected 19 weather stations to report their
seasonal Growing Degree Days (GDD) accumulations. Please compare the cumulative
GDD from your weather station with local GDD recommendations on wild blueberry
crop stages: https://www.novascotiawildblueberryblog.com/p/phenology-tracker.html.
Figure
3. Selected Wild Blueberry Weather Stations and GDD Updates (April 1- June 20)
Table 1. Wild Blueberry Weather Stations and GDD Updates
(April 1- June 20)
