2024 Production Updates and Seasonal Outlook for NS_ 4th Blight Line Post_ May 3

Friday, May 3, 2024

2024 Production Updates and Seasonal Outlook for NS_ 4th Blight Line Post_ May 3


Hi, everyone. We are officially in a Monilinia Blight season for most of the central early/low-ground fields. From the weather forecast, we are going to have some continuously double digital air temperatures in the next 7-14 days which are the peak and the most susceptible timing of the blight in wild blueberry crop fields. We will highlight Monilinia Blight management in today’s post, but I want to remind growers to monitor crop fields and local weather conditions very closely in the next two weeks.

Wild blueberry growers across the province can start pre-emergence herbicide application now. In some early areas, it is getting too late. Please apply herbicides accordingly and sooner.



Growing Degree Days (GDD) Summary

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.

*Please note that Earltown weather station is out of service so we can’t report the latest GDD from this station. We will resume once we see it back online.

Figure 1. 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, May 2, 2024


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

>40%- April 29



Cumberland County


West Advocate

>40%- April 29


>40%- April 29

Halfway River

>40%- April 29







Colchester County



33% F2- May 2

Murray Siding

45% F2- May 2


20% F2- May 2



Halifax Regional Municipality


Middle Musquodoboit

30-40% F2


30-40% F2



Guysborough County

5-10% F2- May 3



Pictou and Antigonish County

5-10% F2- May 3



Cape Breton

0% F2- May 3



Monilinia Blight Management in Wild Blueberry Production

It is important to monitor plant development stages in your fields, especially if this disease has occurred in your fields previously. I encourage growers to go out to the fields and see how floral buds are developing.

When looking at fruit buds do not count obviously dead fruit buds. To do that, you can walk your fields in a “W” pattern and collect 20-30 stems randomly. From those collected stems, count the total number of floral buds and the number of buds at the F2 stage or beyond. You can simply divide the number of F2 buds by the total number and times 100. This would you the % of F2. Please don’t count obviously dead floral buds.

For monilinia to infect blueberry plants, there should be mummy berry spores, blueberry buds at a susceptible stage (F2 and above), and an infection period of long enough wet period and temperature. Only treat for Monillinia when blueberry buds are at least at 40% and before the next forecasted wet period.

For products to prevent monilinia infection, please refer to Perennia’s updated pest management guide for wild blueberry (2021): https://www.perennia.ca/wp-content/uploads/2018/03/Wild-Blueberry-WEED-INSECT-DISEASE-GUIDE-2021-WEB.pdf. Please check with your processors or buys to see what products are allowable in their markets.


Monilinia Blight of Lowbush Blueberry: https://cdn.dal.ca/content/dam/dalhousie/images/sites/wild-blueberry/pdfs/Monilinia_Blight_Lowbush_Blueberry.pdf

Forecasting Mummyberry Fungus Infection: https://extension.umaine.edu/blueberries/wp-content/uploads/sites/41/2010/06/mummyberry-forecasting-handout.pdf