1st Blight Update and Seasonal Outlook for Nova Scotia- April 22, 2022

Saturday, April 23, 2022

 This is the first Monilinia update for 2022.


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



April 20- 6%

Mapleton (Lynn Mt.)

April 20- 5%

Halfway River

April 20- 10%



South West Nova Scotia


Queens County

April 23- 42%

Digby County

April 23- 27%

Annapolis County

April 23- 28%



Hants County




Halifax County




Guysborough County




Colchester County


Murray Siding

April 21- 4.95%


April 21-2.62%


April 21-2.38%

Debert (WBPANS office)

April 21- 0.09%

Debert (Debert Airport)

April 21- 1%



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.


Growing Degree Days (GDD) Summary

Here is a summary of the most up-to-date GDD from weather stations in wild blueberry fields. Please go to the Wild Blueberry Blog- GDD& Phenology Tracker to find out how you can use GDD to predict the wild blueberry stage in your fields.

Figure 2. GDD Summary, April 21, 2022


Other observation- weeds and winter damage


For most of the fields I visited this week and last week, I started to see red sorrel emergence and it concerns me when I saw the numbers of them in the field and the size of them. Look under your hair fescue clipping from last fall as a good layer of grass clipping creates a good barrier for them. Since we still have time before blueberry plants emerge in sprout fields (blueberry plants start to emerge- 270 GDD), I would strongly encourage you to look at your fields and plan for your spring herbicide application to treat red sorrel if needed. If you are planning to use the new herbicide Chikara, you need to treat hair fescue before most plants emerge.

Observation on fields I visited and when I talk to growers over the last two weeks, there is limited winter damage, and it is not a concern like other crop sectors have.