1st Monilinia Update for Nova Scotia, 2021- April 16

Friday, April 16, 2021

This is our first Monilinia update for this year.

We are starting to see buds swelling and some F2 buds are appearing in some early fields.


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


I have a report from fields in Queens County and the percentage of F2 is around 10%. Other fields I visited near the Truro area are not quite at the F2 stage but starting to see buds swelling and close to opening. In those fields I visited, they were at less than 5% F2.

Figure 2. 1st Monilinia Update for Nova Scotia- April 16, 2021


Table 1. 1st Monilinia Update for Nova Scotia- April 16, 2021

Wild blueberry production regions, NS

The average percentage of floral buds at F2 or beyond



South West Nova Scotia






Hants County




Halifax County




Guysborough County




Colchester County

< 5%



Cumberland County




Pictou and Antigonish Counties




Cape Breton


*If you would like to share information with me about the blueberry plant growth stage in your areas, please contact me at 902-890-0472 or email me, hlyu@perennia.ca. I appreciate your information.


General information about Monilinia disease 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 give you the % of F2. Please don’t count obviously dead floral buds.

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 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


The next update will be on Friday, April 23.