Hello, everyone
Here is another quick update on blueberry growth stage
and blight management before the weekend. A low-pressure system is in the
forecast, which is expected to impact Nova Scotia this Saturday, bringing
another wet period and blight concerns for Mainland crop fields. Over the last
three days, the weather system that moved through the region has brought considerable rain to production regions (Figure 1). Combining with
the average daily temperatures during the wet periods, the environment is
suitable for mummy berry cup development and disease infections on susceptible crop
fields.
Figure
1. Rain reports from CTV Weather
Cape Breton fields are still early for Monilinia Blight infection.
Mainland fields:
For Mainland growers, if you made the first blight application on Monday or
Tuesday (May 5 and May 6) or earlier, please note that the protection window is
7-10 days. If you haven’t made a blight application yet and plan to do so, a
spray can be scheduled in the next couple of days, weather permitting. This
would apply to fields in Pictou, Antigonish and Guysborough areas, as the F2
stage is fast approaching 40-50% F2.
Next week (May 11-17), most crop fields and
production regions on the mainland will still be at risk of infection from
Monilinia Blight until we see white, unopened blooms (Figure 2). Some
of Southshore’s fields are nearing the end of the Monilinia Blight season, and
flowers are beginning to open. Generally speaking, most of the other Mainland
fields are about 1-1.5 weeks behind southern fields, so we should continue to
monitor them closely over the next 7-10 days.
Figure 3 is the infection risk table for Monilinia
Blight based on air temperature and wetness hours. As you can see, the current
spring conditions pose a high risk of infection, unlike the last few dry springs
when blight pressures were low.
Some early infection symptoms may be detected in
fields by the end of next week.
Figure
2. Wild Blueberry Susceptible Fruit Bud Stages to Monilinia Blight (DAAF- NB)
Figure
3. Severity Rating of Monilinia Blight Infection Periods (Dr. Paul Hilderbrand,
AAFC)
Lastly, please check out the latest GDD accumulations from
selected stations to estimate crop stages.
Have a great weekend!
Hugh
Wild Blueberry Weather Station GDD and Crop Stage Updates
We selected the following 19 weather stations to
report their seasonal 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
1. Selected Wild Blueberry Weather Stations and GDD Updates (April 1- May 8)
Table 1. Wild Blueberry Weather Stations and GDD Updates
(April 1- May 8)
