2024 Production Updates and Seasonal Outlook for NS_ 1st Blight Line Post_ April 11

Thursday, April 11, 2024

It might sound too early to worry about Monilinia Blight management in Nova Scotia wild blueberry fields, but the earliest fields were around 20% F2 in West Caledonia, Queens as of April 10. Based on the grower’s record, the producer might be looking about 6 days earlier to apply his first monilinia blight in the same field compared to 2022.

In some wild blueberry meetings over the last two weeks, I shared Nova Scotia’s winter weather information, March air, soil and precipitation updates, and spring forecasts. Based on that information, we are seeing more signs of warm spring and early plant development in Nova Scotia.


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

This year, we are going to report GDDs from 17 stations (see Figure 1) 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 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 1. GDD Summary, April 10, 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 1. 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



Cape Breton




Cumberland County




South West Nova Scotia


Queens County

18%- April 10

 Digby county

 8.6% - April 11

Annapolis County

 1.6%- April 11



Halifax County




Guysborough County




Colchester County




Pictou and Antigonish County





General Information about Monilinia Blight and Management


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 dive 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.

Figure 1. Wild Blueberry Floral Buds in F1 and F2 stages.


For monilinia to infect blueberry plants, there should have 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 Monilinia 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 (2022): https://www.perennia.ca/wp-content/uploads/2018/03/Wild-Blueberry-Pest-Guide-2022_FINAL.pdf.

Other available resources:

1.     ATTTA pollinators guide: Protecting Pollinators from Pesticdes- Wild Blueberry.



Our Atlantic Tech Transfer Team is pleased to share their latest guide, Protecting Pollinators from Pesticides – Wild Blueberry! Available in both English and French, the focus of this guide is on minimizing the impacts of pesticides on pollinators in wild blueberry production. Check it out today!






3.     Perennia’s Online Pest Management Guide Tool


We are excited to introduce Perennia’s online pest management guide tool. With this new tool, you will be able to access relevant and up-to-date information about pesticide options in an easy-to-use way. This interactive tool is searchable and will help you save time and improve decision making when selecting pest management products. Organized in tables, these guides can be printed and can be accessed in a way that works best for you.

Please visit this link: https://www.perennia.ca/onlinepestmanagementguide/.