5th Monilinia Update for Nova Scotia, May 14, 2021

Friday, May 14, 2021


This is our 5th Monilinia update for this year.

There are a few things I like to mention in this update:

1.     Sprout-year fields: I visited some sprout fields this week in the Colchester area, and all of the fields I visited have plants emerging and this would be common to see in other areas as well. In sprout fields, most of the common weeds are not hard to see at this stage, including red sorrel, poverty oat grass, hair fescue and other early development weeds. Before blueberry plants actively emerge, the next 1-2 weeks would be a good window for your spring herbicide application. Our pest management guide has the herbicide information, please have a look: https://www.perennia.ca/wp-content/uploads/2018/03/Wild-Blueberry-WEED-INSECT-DISEASE-GUIDE-2021-WEB.pdf


2.     Fruit-year fields:

a.     Most of the areas are at the 40-50% F2 stage now in NS and some late developing fields, such as the Advocate area and Cape Breton are at 32-35% F2. Growers in those areas should be looking closely at their fields and getting ready for spraying once at the 40-50% F2 threshold (Figure 1. and Table 1.).


Figure 1. 5th Monilinia Update for NS- May 14, 2021

b.     Plant development and monilinia infection symptoms: at this time, blueberry fields in NS are looking at the percentage of F2 stage randing from 40%-70% or higher and most of them would be at F4 and F5 now. However, I don’t see much bloom yet in the fields I visited. It is starting though, and the bloom is ranging from 0-5% this week. It is too early to see any symptoms. After the infection period, if plants are infected by monilinia, it would start to show symptoms 7-10 days after. At this stage, I don’t have data or reports from the region yet.  



c.     Botrytis: I have growers asking about Botrytis already which is good to consider ahead of time. Botrytis spores are produced begging at early bloom, so I would expect once we reach the bloom period, then the infection risk is high and control measures should be conducted. In NS, areas near the coast and fields that have regular fog and wet periods will have a high risk for Botrytis. I will start giving updates on Botrytis once we are at the infection period.


d.     Field activities to consider for fruit fields: Monilinia control is still a top priority this time of the year and growers should be looking at Botrytis controls (registered products and field monitoring) and also getting ready for pollination once we are in the bloom window. Since the pollination time is also the time that a lot of growers will be using fungicides, so please make sure you are spraying with caution and minimize the risks for bees while applying fungicides.



Table 1. Monilinia Update for Nova Scotia- May 14, 2021

Wild blueberry production regions, NS

The average percentage of floral buds at F2 or beyond



Cape Breton




Cumberland County




East side of Farmington


Pigen Hill


Port Greville


Webb Mt.


Lynn Mt.



Greater than 40%


Greater than 40%


Greater than 40%


Greater than 40%


Greater than 40%


Greater than 40%

Collingwood and Windham Hill

Greater than 40%


Greater than 40%

Half way River

Greater than 40%



South West Nova Scotia

Greater than 40%



Hants County

Greater than 40%



Halifax County

Greater than 40%



Guysborough County

Greater than 40%



Colchester County

Greater than 40%



Pictou and Antigonish County

Greater than 40%


The next update is on May 21st.