2023 Updates and Seasonal Outlook for NS_ 8th Blight Line Post_ May 16

Tuesday, May 16, 2023

This update will focus on Monilinia Blight as we are in a critical time for blight risk in Nova Scotia!!!



Growing Degree Days (GDD) Summary and Plant Development Updates

Figure 1. GDD Summary, May 16, 2023



Please find where you fit and plan accordingly.


Early fields in Nova Scotia (Southshore counties and early fields/regions in Cumberland, such as Newville Lake, Halfway River and Kirkhill):

·         Fields in those areas are in the early-flower stage (before bloom, Figure 2)

·         This week should be the last week for those fields to pass this year’s monilinia infection, but I would still be cautious as you might need to put another blight spray on. Please check your field and farm records.

·         For those areas/fields, I haven’t found monilinia infection symptoms yet. I tried to find them but didn’t see anything in the fields. We are probably having another lucky year in terms of monilinia infection.



Figure 2. Wild blueberry early flower stage


Late fields and Cape Breton fields:

·         Those fields are very close to 40% F2 or some might be past 40% F2 already. I probably won’t worry about the next two day’s showers for those areas. I would pay attention to weather forecasts after mid-week.

·         Those fields are still in a safe window to apply pre-emergence herbicides, but the window is very narrow.


Central fields:

·         All areas/fields in central NS are at risk for monilia infection. That’s why I said this is a critical time for NS fields as the crop stages are in an ideal condition for blight infection and we are going to get some showers here and there.

·         Remember, an application will provide 7-10 days of protection.

·         Most of the growers in those areas would have applied first application around the weekend of May 6 so technically a second application might be needed.

·         Some of the growers applied their first application around the weekend of May 16, and this would give them a protection window up to the Victoria Day weekend.



We are not out of the woods yet! Our crop fields are still under the susceptible period (Figure 3)


Figure 3. Susceptible stages of wild blueberry to monilinia blight infection


The 5th and 6th stems from left to right are where we are now.

Next update, May 19, Friday.