BlueFocus Newsletter- May 2022

Friday, May 20, 2022


(Perennia’s Wild Blueberry Newsletter)

Dear Growers,

We are fast approaching bloom and pollination season and we are expecting to see beehives out in crop fields this long weekend. In sprout fields, plant emergence ranges from 10% to 50% and most of you should finish spring herbicide treatments by now as it is late to put any herbicides that would damage blueberry plants. Please see the details below.

Thank you for your ongoing support! Have a great long weekend!


Hugh Lyu

Wild Blueberry Specialist, Perennia; 902-890-0472.

May 20, 2022

Table of Contents:  

NS Wild Blueberry Production Update

Upcoming Management Recommendations

Insect Traps

Upcoming Events


NS Wild Blueberry Production Update

Plant Development and Growing Degree Days in 2022 (NS)

If you remember what the season was like in 2021, you are experiencing the same development trend for this season! Fast plant development!

The figure and table below summarized growing degree days from a weather station in Kentville. From March 1 to May 16, we are in a similar GDD and development trend as 2021 and certainly above the 5-year average in plant development.

Figure 1. Degree Days Accumulations as of May 16, 2022, Kentville weather station, Provided by Jeff Franklin (AAFC)

 Table 1.0 Degree day accumulations as of May 16, 2022.  All data are taken from the Kentville weather station, based on a start date of March 1, and calculated using the single sine method.






5 year average

10 year average

Plant development (Base 5ºC)







Insect development (Base 10º)







In wild blueberry fields, we observed fast development after we got into May and especially in the last two weeks. I have seen fields go from 30% F2 to 50% F2 in two days and one of the reasons is the increase of heat accumulation in the soil. We also observed that it took a very short time for plants to develop from bud stage (F2, F3 and F4) to bloom stage (early flower stage, pre-bloom). Normally from 80% F2 to bloom stage, it would take another week but this year, they advanced very fast. I heard comments from growers: “I don’t think I saw blueberries advance this fast!”.

More direct data and information on wild blueberries: the below figure (Figure 2) shows how fast and many GDD accumulated in the last 7 days.

Although we are excited about dry and warm weather during the monilinia blight season, the fast development trend means when we get into bloom and pollination season earlier and we might be getting a higher frost risk if there are low temperatures during the full bloom period.

Figure 2. GDD accumulation since April 1 from weather stations in wild blueberry fields.

Figure 3 shows the most current (as of May 19) GDD summary from weather stations in wild blueberry fields. As I said, when we compare those numbers to the wild blueberry GDD model, we are looking at 10% to 50% plant emergence in sprout fields. In crop fields, stems with open flowers just started but some areas are getting into 10% to 25% bloom.

I hope you have a chance to check and use this new GDD tool we developed this year and get something out of it to help with your management.

Figure 3. Wild Blueberry GDD Summary, May 19, 2022

*Lynn Mt station was up to date as of May 11.


Winter Damage and Yield Potential in 2022

As I mentioned in April’s newsletter, we observed minimal winter damage in early spring and by far, everything seems to be cooperating. We are seeing great yield potential from fruit bud numbers and sizes. We all look forward to a great year!  

I also heard from a few growers about their feelings towards this year, “So far, everything is going very well and I am seeing great yield potential in my fields. I would say this is probably the best year in 6 years.”


Overwinter Beehive Health

Since my last update about this topic, I didn’t hear many new updates about overwinter beehive damage. We know we had a higher percentage of winter losses compared to previous years, but the damage level is in an acceptable range in NS. In other regions, getting sufficient pollination is going to be a challenge this year. We are expecting a full report on overwintering beehive damage by mid-June, and I will update this in June’s newsletter.


Monilinia Blight

This year, I continued to give % of F2 updates on fields I visited and information getting from growers and farm staff. Thank you to those who shared information with the industry. We are getting to the end of monilinia blight infection season for this year and we did observe some infection periods through the susceptible period. We haven’t seen symptoms yet, but we should start to find leaves and blooms with infection if fields didn’t get treatments or applications were made at the wrong timings.


Other in-field observations

There are two things I like to share from observations made by myself and others.

During F2 scouting, I saw some fields with patches of blueberry stems with damaged and brown flowers and fruits. This is likely due to the late fall flowering of the previous sprout year. We observed plants producing buds and flowers in the late fall last year in sprout fields. This is not in a high percentage of fields in the province and I only saw this in a couple of fields I visited but worthwhile to share and bring this to your attention.

Figure 4. Damaged flowers and fruits from previous fall late development stems

This year, we also saw blueberry emerge from cut stems that were buried under snow and got protection from snow coverage. This early plant emergence could affect spring herbicide application timing.

Figure 5. Blueberry emergence from cut stems


Upcoming Management Recommendations


Crop fields

Pollination is the main priority after this long weekend towards June. Please start your communication with your beekeepers and make sure you talk to them if you decide to spray any products when bees are in the fields.

Botrytis Blight: If you are in areas where typically more prone to botrytis infection, such as coastal areas, wet/fog areas and if your fields are weedy (sheep sorrel is an important host) with very dense patches, you should consider and monitor the situation for treatment application. The fungus begins to sporulate at early bloom, so the best time to apply (if needed!) the first application is when about 30-40% of the flowers are open. Closed flowers are resistant to infection. A second spray can be applied about 7-10 days later.

Insects: trapping and monitoring concerned insects in your areas and fields. Please see the information below for places you can get traps.


Sprout fields

Weed control: spot treatments and mechanical weed control (pull or cut weeds above the blueberry canopy before plants produce seeds).

Leaf disease control: considering and planning leaf disease control, such as Septoria leaf spot, leaf rust and powdery mildew. Please check out our 2022 pest guide to find products to help with your management:


Insect Traps

Some of you might start thinking about getting insect monitoring traps early due to supply chain delays. WBPANS carries traps in the office, so please give them a call and check if you can get the things you need (902-662-3306;

Great Lakes IMP ( also has great selections of monitoring tools.


Upcoming Events


Please check out the event page under the wild blueberry blog for more details.

Perennia- Weather Station Apps and Website Training Session (online)

Date and time: May 24, 2022 (Tuesday), 7-8:30 pm

This training session is intended for producers who have purchased weather stations from Perennia under the Nova Scotia Weather Station Assistance Program but is open to anyone who would like to learn more about weather stations and how they work. It will provide an overview of the Davis weather station components, basic maintenance and using the apps and software tools.

To register


WBPANS- 2022 Twilight Meetings


Session 1: May 31, 2022, 6-8pm

Location: 168 Dakota Rd, Debert, NS (WBPANS office)

Demonstration of UAV, prescription map and modified sprayer system from the CWBIRDI PAN-Atlantic project. Dr. Percival and his team will demonstrate the work of the UAV system, the creation of in-field prescription maps and how the modified sprayer can use these maps to apply pesticides precisely to a wild blueberry field. Growers will see how these systems work and have the opportunity to ask questions about how they could be used.


Session 2: June 7, 2022, 6-8pm

Location: TBD

Demonstration and discussion of weather station use in wild blueberry fields.

More details to share once WBPANS releases the information.


WBPANS- 2022 Field Day

Date: July 19, 2022

Location: 648 Sherbrooke Road, East River Saint Marys, NS (John Cameron’s receiving shed)

WBPANS will host the 2022 Field Day on Tuesday, July 19, 2022, at John Cameron's receiving shed in East River Saint Marys, NS (648 Sherbrooke Road). The Field Day will return to an in-person format for 2022 with equipment & agri-business displays and field tours. Stay tuned for more details!