2024 Production Updates and Seasonal Outlook for NS_ 3rd Blight Line Post_ April 24

Wednesday, April 24, 2024

 Hi, everyone. Here is the mid-week update. The weather is looking good for the next few days across the province. We are expecting to see double-digit air temperatures continuously. We are observing field/natural signs of plant development and growth acceleration, such as the emergence of lily of the valley, bunchberries, green grasses, as well as blueberry sprout field bud development.

The next possibly concerning wet periods for growers in the early areas of central NS is from mid to late next week (Monilinia blight spray).


NS Cumulative Precipitation

Source: Jeff Franklin (AAFC Kentville) and Michelle Cortens (Tree Fruit Specialist, Perennia, Orchard Outlook Newsletter Vol. 24 NO 2.). Figure 1 is a graph of cumulative precipitation over the last five years including rainfall and the rainfall equivalent from snow. Rainfall contributed to most of this year's cumulative precipitation. Jeff Franklin shares that, "The cumulative precipitation plot shows that we are currently above the 10-year trend and that most of our precipitation has come in March and early April with some significant single day rainfall events. It also shows data from 2019, when we received our precipitation in smaller more frequent events. The data from 2019 shows that we had rain on 40 days in the months of April and May!"

Figure 1: Both rainfall and the rainfall equivalent from snow at the Kentville Research Station from 2019 to 2024. Provided by Jeff Franklin (AAFC).


Growing Degree Days (GDD) Summary and 2024 Spring Plant Development Prediction

This year, we are going to report GDDs from 17 stations (see Figure 2) 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 2. 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 3. GDD Summary, April 22, 2024



Plant Development and Management Recommendations for the Next 7 Days


Sprout fields:

If the weather station you follow reaches above 90 GDD as of April 22, I would recommend growers use the dry window for the next few days to spray pre-emergence herbicides (Chikara, Ignite, Spartan/Involve 50 WDG, Velpar and their tank mixing). The next wet/rain is looking around mid-week for the most of central early growers. It is also good to spray herbicides a few days before the forecasted rain as wet soil improves those chemicals’ efficacy, especially Chikara and Ignite.

If the weather station you follow is still below 80 GDD, after this warm and dry week, you would be looking around the first few days in early May to spray pre-emergence herbicides in your sprout fields.

Crop fields:


Fields in the Southshore areas, West Advocate and Halfway River (near Parrsboro) are in the early to mid stages of monilinia infection. Growers in the above-mentioned areas should monitor field and weather conditions closely for the next few days. The first monilinia blight spray might be needed very soon.

Other areas are still early for monilinia blight infection.

Here is another piece of information I want to share from the Highbush Blueberry Monilinia Blight Management network by Sonny Murray (Berry Specialist, Perennia, Monilinia Blight Forecast Post #1 April 22nd.)

Newly emerged apothecia (the structure produces disease spores) have been observed in the Waterville and Aylesford areas (Annapolis Valley). Please note, that this is just a piece of additional information to help us determine this season’s monilinia blight infection window in wild blueberries. Normally, the central wild blueberry fields are about 2-3 weeks behind the Annapolis Valley’s highbush blueberry development in the spring. This is also a warning sign that this spring condition is favourable for monilinia blight apothecia development, given the wetness and warmness we have.


Figure 4. Highbush Mummy Berries Apothecia, from Sonny Murray

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

>40%- April 24



Hants County

10%- April 19



Cumberland County


West Advocate

20% F2- April 19


10-15% F2- April 19

Halfway River

30-40% F2- April 19



Colchester County



9% F2- April 23

Murray Siding

20% F2- April 23


13% F2- April 23



Halifax Regional Municipality


Middle Musquodoboit

10%- April 23


5%- April 23



Guysborough County

0% F2- April 19



Pictou and Antigonish County

0% F2- April 19



Cape Breton

0% F2- April 19