BlueFocus Newsletter- June 2022

Tuesday, June 14, 2022



(Perennia’s Wild Blueberry Newsletter)

Dear Growers,

I hope all of you have had a great season so far. In this month’s newsletter, I will share updates from NS, and other production regions (Maine, QC, NB and PEI). We have a few field days coming up in July, so please remember to check out our event page.  


Hugh Lyu

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

June 14, 2022

Table of Contents:  

Nova Scotia and Other Production Regions’ Updates

Upcoming Management Recommendations

Weather Station Apps and Website Training Session- Recorded Video Available

WBPANS 2022 Twilight Meetings Highlights

Upcoming Events


Nova Scotia and Other Production Regions Updates


NS Wild Blueberry Growing Degree Days and Crop Updates


Figure 1. Wild Blueberry GDD Summary- June 13, 2022


The average of GDD accumulations from all stations was 659 (as of June 13). We have many different production regions in the province with different crop stages, but in general, we are looking at plant emergence in sprout fields reaching 90% and the tip dieback stage is about to start. Most early and middle fields are looking to the end of pollination, and in areas like Advocate and Cape Breton, fields are still in the early to the mid-bloom stage.

Overall, this growing season has been going well with great yield potential if things stay adequately.

To this point, here are a few summary points about pests according to personal observation and communication with growers:

1.     Low monilinia infection due to dryness during susceptible crop stages (F2 to before bloom).

2.     We observed early development and noticed more red (sheep) sorrels this spring.

3.     I noticed more and fast development on grasses, such as poverty oat grass, common vetch, colonial bentgrass, witch grass and woolly panican grass. Last but not least, hair fescue.

4.     Broadleaf weeds: spreading dogbane, goldenrods, and hawkweed.

5.     We had some good pollination days in the last few weeks.

6.     2 major frosts in the mainland area didn’t cause significant damage to flowers across the province.


I also received updates from other regions’ specialists, here is the summary:



Last year's bud set was good due to rain in July and dry, sunny conditions otherwise. They had a very warm fall and didn't see a frost until October which is late for them. They've had a good bloom and pollination weather so far. Peak bloom was over. They have the usual amount of mummy berry, blueberry flea beetle and span worm. Spanworm seems to have enjoyed the warm fall conditions with more life cycles last season than is typical. 


No winter damage was observed in the spring. They are in middle bloom now. Similar to us, their frost events didn’t cause significant damage.

Quebec growers are experiencing a beehives shortage. On the fortune side, there was a good dispensability of bumble bees.


In the most region, there was little winter damage, observed.  Fields' growth stage is within a few days from the previous years.  Early spring weather made it seem like the crop was advanced, but things are returning to average dates.

Honey bees – There have been mixed reports of losses, a few medium operations had significant losses, but most larger commercial operations have losses similar to the previous year (ranging from 10-20%).  As the many blueberry growers depend on honey bees from Ontario, beehive availability is an important factor for NB’s crop yield in 2022.

Many growers in Northeastern NB also depend on the Alfalfa Leafcutter bee for pollination, and demand is staying stable or increasing.  As well, more growers ordered commercial bumble bee quads, as part of their pollination strategy. It is early to tell, but fruit bud numbers look good. 


The sprout fields last year set floral buds well due to the favourable weather and the winter weather was generally favourable as well (above average snowfall).

The Spring Monilinia season was not severe due to bouts of dry weather during the susceptibility period. There is a lack of honey bee hives on PEI this year which will hinder the crop’s yield potential.


Upcoming Management Recommendations


Sprout-year Fields:

·       Weed management: pull or cut weeds above the blueberry canopy before they go to seed or cut weeds to the base. If needed, apply selective post-emergent herbicide, such as Callisto 480 SC

·       When wild blueberry plants' growth stage reaches tip-dieback (black top on the top of plants), consider leaf tissue samples for nutrient analysis and take soil samples for pH analysis.

·       Leaf diseases control: apply fungicides for leaf diseases control, especially if high levels of leaf loss have occurred in the past


Crop-year Fields:

·       Weed management: pull or cut weeds above the blueberry canopy, especially in areas weeds are too tall that might hinder harvester operation

·       Insect management: preparing monitoring traps and monitoring for SWD and blueberry maggot


Weather Station Apps and Website Training Session- Recorded Video Available


The webinar recording for the Weather Station Apps and Website Training Session is now available on the Perennia YouTube channel.

You can find the link here:


WBPANS 2022 Twilight Meetings Highlights


This year, WBPANS organized two twilight meetings on May 31 and June 7. Here are some highlights from both meetings.

On May 31, the first meeting was held in Debert. Dr. David Percival and his group presented three topics:

1.     Improving agrochemical delivery efficiency and deriving canopy characteristics by use of UAV and remote sensing technology, by Joel Langdon

2.     Selective agrochemical and nutrient application to reduce production costs, by Daniel Mahoney

3.     Assessing fungicide efficacy for improved management of the wild blueberry foliar disease complex, by Alex Cornel


Figure 2. Joel Langdon introduced UAV and remote sensing technology


Figure 3. Daniel Mahoney talked about new sprayer technology


On June 7, the association and Perennia organized and presented the second twilight meeting in Parrsboro. We had a great turnout at the meeting.

Perennia’s Agri-technology Specialist, Thomas Harrington gave a detailed introduction to the Weather Station Program and a few data use examples. Wild Blueberry Specialist, Hugh Lyu, also talked about a few great ways to utilize the program and collected data to guide this season’s production and management.  



Figure 4. Thomas presented on the weather station program



Figure 5.  Peter Burgess (Executive Director, WBPANS) and growers


Upcoming Events


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


We have a couple of wild blueberry field days coming up in different regions in July. I only showed as many details as I know about those field days in this newsletter, so please check with each region for more details.


·       Perennia tailgate meeting- Compost and Cover Crops, July 11, 1-3 pm

Location: Soil Mates Farm, 297 Farmington Rd, Barss Corner, NS

More details and registration:


·       Maine Blueberry Hill Farm Field Day, July 14

Location: Blueberry Hill Farm, 1643 Rt 1, Jonesboro, ME

This year’s big field day will feature a morning of IPM with UMaine researchers, burgers on the grill for lunch, followed by an exciting afternoon with the following sessions: Improved Harvesters, Fresh Pack Technology, Drought Management, and Commission Updates.

More details and registration:


·       Quebec Field Day, July 14, Normandin, Quebec


·       WBPANS Field Day, July 19

Location: 581 West Side Road, East River Saint Mary’s, NS

Pre-registration is required! Please contact the WBPANS office to register before July 7,

2022 by phone: 902-662-3306 or email:


·       Bleuets NB Blueberries (BNBB) Field Day, July 21, Aulac, NB

2022 Updates and Seasonal Outlook for NS_ June 10

Friday, June 10, 2022

2022 Updates and Seasonal Outlook for NS_ June 10


2022 Degree Day Accumulations and Crop Update

Table 1.0 Degree day accumulations as of June 6, 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)







Here is a summary of 2022-degree day accumulations from the Kentville weather station. This summary gives us an idea of where we are at in terms of this season’s growth and development. In NS, we are above both 5-year and 10-year averages (383.1 GDD vs 342.9 GDD and 360.2 GDD). 

Here is another GDD accumulations update from wild blueberry weather stations:

Figure 1. Wild Blueberry GDD Summary- June 9, 2022

The average of GDD accumulations from all stations was 591. As we have many different growing regions with different development stages in the province, it is hard and unrealistic to give a solid statement about the whole province’s crop development. However, in general, we are looking at more than 50% to 90% plant emergence in sprout fields in NS. In fruit fields, we are at 90% open flowers, with some early to middle fields getting to more than 50% petal fall (pin head). Even late fields, such as Advocate and Cape Breton Island, fields are in the early to middle flowering stages.

As I mentioned in the last update, we observed low diseases infection for this season due to the dryness of the weather.


Weed Management in Sprout Fields and Use of Callisto 480 SC (mesotrione)

During this time of the year, activities can be and should be done in sprout fields including weed management. Growers can pull or cut weeds above the blueberry canopy before they go to seed or cut weeds to the base. If it is necessary, some selective post-emergent herbicides, such as Callisto 480 SC (mesotrione) can be used to control a wide range of broadleaf weeds.

Here is a little bit of information about using Callisto to achieve effective weed management.

Blueberry growers have observed more crop injury when applications are made under hot and/or humid conditions or when the crop is stressed from flooding. The injury is most visible where excessive rates have been applied, such as sprayer overlaps. If heavy rain is expected within 48 hours, an application should be delayed. For improved crop safety, make applications under cooler conditions (early morning or evening) or when daytime temperatures are below 21 °C.


Pollination and Determining Percent Fruit Set in Wild BLueebrry Fields

In general, genetic factors of wild blueberry plants play a critical part in affecting pollination, other factors also contribute to and influence the overall pollination rate. Those factors include weather, plant vigour, distribution of clones and the population of pollinating insects. Because there are so many factors to affect pollination, it is not realistic to achieve a high % fruit set of 75 to 100%.

In general, pollination rates of 40 to 50% are considered very good, while 50 to 60% would be considered excellent. If the rate is below 30%, this shows the pollination force is too low.

Growers will get the benefits to understand and know how to determine the % fruit set. When growers know their % fruit set, they will be in a better position to understand their field and productivity, as well as help them to improve their production practices.

There is a great factsheet from the Department of Agriculture in NB that talks about determining % the fruit set in wild blueberry fields. Here is the link to this factsheet, but you can read the information below to get quick access to this information.



Information from the factsheet:

When you sample a field, you should sample ALL the field. Since conditions may vary from field edges to field centres, you will need to sample both types of areas unless you are trying to compare them. If you sample a big area, then you will need to take more samples. Fifty to one hundred samples seem to be adequate for a twenty acre field.

Walking your field during early to mid-bloom, you will take RANDOM samples by crossing the field back and forth in the shape of a "W", as you would for soil sampling. At each one of the sites at which you stop, you should sample in the following fashion:

  1. You will be following the progress of one stem at each sample site. At each site, drop a pen or a similar small object and sample the stem which is located closest to where the object falls. This will keep your sampling random. You can identify the stem by tying a piece of coloured synthetic string loosely to the stem, below the flower stalk (known botanically as a raceme). Place a brightly colored flag right next to it, so that you can locate the general location of your sample stem. Identify the sample number with indelible ink on the flag, and record this number and the information described below in a log book.

Figure 2. An example of tagging and flagging study stems


When sampling at early to mid-bloom, you would be counting and recording the TOTAL NUMBER OF FLOWER STRUCTURES which are found on the sample stem (this includes unopened blossoms, open blossoms, and blossoms which have lost their petals).

  1. Prior to harvest just when most of the fruits have turned blue, return to the same sample and count the TOTAL NUMBER OF BERRIES which will produce a harvestable fruit. Do not include the "pinheads" (those fruits which have larger crowns than berries).

  2. Use the information from (1) and (2) to determine the percent fruit set for the sample site, and then combine the information to learn the average percent fruit set for the field.

Here is an example:

  • From section 1. The TOTAL NUMBER OF FLOWERS e.g., 70 unopened buds, open flowers, flowers without petals
  • From Section 2. The TOTAL NUMBER OF BERRIES e.g., 35 harvestable berries
  • PERCENT FRUIT SET = (35 / 70) x 100 = 50%

To calculate the percent fruit set for the field, add all the sampling sites and divide by the number of sites. If the differences between the sampling sites are very big, you might consider taking more samples next year OR you might try and figure out why. Some growers claim to get up to 70% fruit set; so if your figures are really low, you know that the top priority for managing that field is bees.

You can also use this method to calculate differences between your fields or differences that you might have from using or not using hives.



I will issue June’s Perennia Wild Blueberry Newsletter (BlueFocus) early next week. Stay tuned for the issue. We have some updates to share!

Have a great weekend!







Frost Advisory in Cape Breton Island

Tuesday, June 7, 2022

Environment Canada issued a frost advisory for all counties in Cape Breton Island. 

Fields in the area are in the open flower stage which is at risk of low temperatures. 

I want to share this graph again to remind you of the frost risks of different blueberry stages. 

2022 Updates and Seasonal Outlook for NS_ May 31

Tuesday, May 31, 2022


This May has been very dry, and we are below the 10-year average of May rainfall amount in NS. The dry environment is helpful during disease season (less infection!), however, as we are in the middle of bloom and pollination season, we need adequate rainfall to make successful pollination. We had two frost events so far, but they didn’t cause significant damage to bloom. However, I noticed a little bit of frost damage in some fields.

Many growers are wondering how to tell the differences between frost damage and disease infection on leaves and flowers. I read a very nice factsheet about this topic, and I like to share some key information about them. This factsheet and all information I share below is from Wild Blueberry extension service, University of Maine. Thank you for them to produce many resources for the wild blueberry industry.


As I said, this year’s monilinia blight disease pressure is low, but we are still in the middle of bloom and any long, warm, wet periods are ideal for Botrytis infection.


Upcoming Events

Please check out the Wild Blueberry Blog Event Page where I just updated a few events in the calendar.

Two events to highlight:

1.     WBPANS- 2022 Twilight Meetings Session 2: Thomas Harrington (Perennia's Agri-technology specialist) and myself will lead the session, focusing on weather stations. 


Perennia Horticulture Tail Gate Meeting in Tatamagouche (June 6; 10 am-12 pm), Mill Creek and North Lochaber.


A special note: I will join the one in Tatamagouche on June 6. If any of you like to meet and bring questions, I am happy to meet old friends and get to know some new faces.



10th Blight Update and Seasonal Outlook for Nova Scotia- May 24, 2022

Tuesday, May 24, 2022

I hope you all had a great long weekend!

This is the last update on Monilinia blight for this season, but I will continue to share things through the season.

There are three things I want to share in this post:

Another frost advisory for the province

Monilinia blight infection symptoms from this year

Rainfall amount and soil temperatures in NS 2022


Another frost advisory for the province

There is another frost advisory issued for the province, please visit this link for more details: Minimum temperatures: zero to plus 6 (coolest in low lying areas).

Are you wondering if the temperatures will damage wild blueberry blooms? Please read our 8th update about this topic:


Monilinia blight infection symptoms from this year

As I mentioned last week, we are expecting to see monilinia blight symptoms this week and we have something to share!

We observed symptoms on both leaves and flowers (Figure 1) from a field in Greenfield (near Truro). By looking at those infected stems, the primary infection occurred around 2 weeks ago.


Figure 1. Infected stems (photo credit: Sarah Schaefer, Perennia) 

I haven’t received any reports and information from growers about this year’s monilinia infection, but this could be a low infection year because of the weather we had during infection periods. I encourage you to take a look at your fields and please share if you notice anything would concern you.


Rainfall amount and soil temperatures in NS 2022

This information was received this morning and data were generated by Jeff Franklin (AAFC Kentville; thank you, Jeff).

From May 1 to May 24, we received only 26.5 mm of rain (Kentville weather station). This is lower than the 10-year average of 69.3 mm (for the entire month of May). In 2021, we had 106.0mm of rain in May. This drier condition potentially reduces monilinia infection risk in May for this season but it is getting too dry and we need more moisture for blueberry plants as well as other crop sectors in the province.

On the soil temperature side, we are well ahead of the 10-year average and 2021 temperature (Figure 2). Soil temperature and plant development are strongly related. We are seeing fast plant development from bud stages to bloom in early May and the soil temperature plays an important role to cause this for the season. As I mentioned previously about rainfall amount, the drier condition is an important factor resulting in higher soil temperatures.

 This is an interesting season and we just need to watch closely as the season progress. 

Figure 2. Average soil temperatures in NS (Jeff Franklin, AAFC Kentville)

9th Blight Update and Seasonal Outlook for Nova Scotia- May 20, 2022

Friday, May 20, 2022

 The main focus of this post is to update the monilinia blight for the season.

By now, most fields in central NS are beyond the risk of primary Monilinia infection. Primary infection refers to when ascospores infect open leaf and flower buds during the blueberry susceptible stage (above 40% F2 and wetness period; point 3 in Figure 1). In general, if the crops have reached the stage where the leaves have unrolled or the first blossoms are visible, the susceptible period is past and sprays are not required. As you can see from my other posts and updates, as well as your observation from fields, we are around 10% to 50% of blooms in the province depending on your area. However, the best indicator would be if apothecia cups still produce spores. We didn’t have mummy berry plots to monitor apothecia cups in wild blueberries, but reports from highbush blueberries showed that all apothecia cups were dried up in the Annapolis Valley area. Thanks to Sonny Murray’s report. Therefore, we are expecting the same development trend in lowbush blueberry fields. We got a lot of heat over the last few days, and it was dry over the last few days as well. This is helpful to dry up apothecia cups. Most apothecia cups will dry up by now.

Figure 1. Monilinia Blight Infection Cycle

Cape Breton is still under infection period as fields are just beyond the 40% F2 threshold. Growers in the area should still pay attention to their plant development and weather forecast.

This year, most growers were able to get through the monilinia season with 1-2 applications. If fields have a primary infection, symptoms will show up on leaves and flowers and symptoms will start to show over the next week or so (Figures 2&3, photos from 2021). We encourage growers to check their fields and note if there are infections that occur in their fields. This would help growers to evaluate their application program and determine better application timings and choose products for next season.


Figures 2&3 Monilinia blight infection on flowers (top) and leaves (bottom), photos from 2021


Secondary infection (point 4 in Figure 1) refers to when infected tissues from the primary infection period produce conidia and those spores move to other healthy flowers and cause infection which will end up producing mummy berries as plant development continues. This phase is impossible to control so the primary infection period control becomes extremely important. If you observe primary infection symptoms in your field, it is good to mark the area and before harvest, collect those mummy berries to prevent future season infection.

As I mentioned in the last update, during bloom time, growers should start to arrange bees and potential botrytis blight control if your fields are prone to this disease.

Have a great long weekend!