Hi everyone,
After last week's unseasonably cold and wet weather, we are finally expecting several favourable days this week that should significantly improve pollination conditions. This year's bloom and pollination period appears to be longer than in recent seasons, when pollination was often compressed into a one- to two-week window. Uneven bud development resulting from last year's drought stress, combined with this spring's weather patterns, has contributed to a more extended bloom period across many fields.
Most fields are currently in mid- to full bloom. This week will be particularly important, as many flowers that remained unopened during last week's rainy weather are now opening and will require favourable pollination conditions to maximize berry set and fruit quality.
In addition to pollination, growers should continue to monitor two other important challenges during the bloom period: frost events and disease management, particularly Botrytis Blight and Septoria Leaf Spot.
Please review the crop updates below regarding
upcoming management priorities and post-frost evaluations.
Crop Fields’ Upcoming Management
Monilinia Blight (Mummy Berry Disease)
Infection Symptoms
·
The primary infection period for Monilinia
blight was relatively short this season due to rapid crop development through
the F2 stage, combined with dry and windy field conditions during the key
infection window.
·
Many growers applied a single blight
fungicide application, which should provide sufficient control under the
disease pressure experienced in 2026.
·
Symptoms resulting from primary infections
caused by ascospores are now beginning to appear on fully expanded leaves and,
in some cases, on unopened flower clusters.
·
This week and the coming weeks provide an
excellent opportunity to scout fields for Monilinia blight symptoms while
conducting other field activities.
·
Infected shoots typically exhibit blighted
leaves that become brown and wilted.
·
Identifying infected areas now can help
assess disease incidence and evaluate the effectiveness of this season's
disease management program.
Bloom-Period
Disease Management
- The two most important diseases affecting wild
blueberry production during bloom are Botrytis Blossom Blight (Grey
Mould) and Septoria Leaf Spot.
- Timely fungicide applications during the bloom period
are effective in reducing disease infection and protecting yield
potential.
- If you have not yet applied a bloom-period fungicide
but are planning to do so, consider making the application as soon as
field and weather conditions permit.
- The warmer temperatures forecast later this week,
combined with recent and expected moisture, are favourable for Botrytis
Blossom Blight infection. These conditions can also promote the
release and dispersal of Septoria spores (conidia), which are
spread by rain splash and prolonged leaf wetness.
- Fields with a history of Botrytis Blossom Blight or
Septoria Leaf Spot should be monitored closely throughout bloom,
particularly following extended periods of wet weather.
- Maintaining adequate disease protection during bloom is
important for minimizing flower infection, preserving fruit set, and supporting berry yield and quality later in the season.
2026 Frost Events and Damage Assessment
Over the past two weeks, we have experienced two significant frost events
across many wild blueberry production regions. Both events lasted multiple days
(May 22–24 and May 31–June 2), and frost injury to open blooms has since been
observed and reported from several areas of the province.
At this stage of crop development, frost injury can sometimes be mistaken
for symptoms of Monilinia blight. However, there are several key differences.
Frost damage typically affects most or all flower clusters on an individual
stem, particularly when flowers are fully open and exposed during freezing
temperatures. In contrast, Monilinia blight infections are often limited to a
single flower cluster or shoot, while neighbouring clusters on the same stem
remain healthy.
The severity of frost injury is also closely related to flower development.
Closed or partially opened flower clusters generally have greater tolerance to
freezing temperatures and often sustain less damage than fully open blooms.
Growers are encouraged to conduct post-frost assessments over the coming
days as symptoms become more visible. Evaluating the extent and distribution of
flower injury will help determine potential impacts on fruit set and yield.
These frost events pose another significant challenge for the 2026 crop,
adding to existing concerns about the 2025 drought, pollination conditions and
disease management. The overall impact on wild blueberry production and
provincial yield potential will become clearer as bloom progresses and fruit
set begins.
Table 1. Wild Blueberry Weather Station GDDs Updates
