2024 Production Updates and Seasonal Outlook for NS_ 7th Blight Line Post_ May 15

Wednesday, May 15, 2024


Hello everyone, 

Here are the mid-week wild blueberry production updates. The weather across the province is looking decent and there are some good windows to spray.

Wild blueberry crop fields in Nova Scotia are in the middle to late susceptible period to Monilinia Blight (Figure 1). Please monitor your local weather forecasts and crop development to plan management activities accordingly.

 


Figure 1. Susceptible stages of wild blueberry to Monilinia Blight infection

 

GDD Updates_ May 14, 2024

 


Figure 2. GDD Summary, May 14, 2024


Wild Blueberry Sprout and Crop Development Stages


Sprout fields:

Pre-emergence herbicides should be applied ASAP. Sprout fields and areas with more than 230 GDD are risky to receive treatment applications, especially if you are going to put on Chikara and Ignite.

 

Crop fields:

Most areas in mainland Nova Scotia are now well above the 40% F2 stage of plant development which makes them susceptible to infection. A couple of sites we monitor in the Cumberland area are around 80-90% F2 in a tight cluster stage (Figure 3). Watch and monitor your weather forecasts closely. Higher temperatures require less duration of wetness to bring a high risk of infection. We are looking at around 15- 20 degrees Celsius in the next couple of days/

Please note, that an application should give protection to plants for about 7-10 days. If you already applied 1st spray, please check your record and note your own protection windows. There is a chance a second spray might be needed if we are getting some wet periods in the next few days.

We also recommend growers apply fungicides before a forecasted rain or soon after the rain stops and your fields are dry. Ideally, within 48 hours.

 


Figure 3. Wild blueberry tight cluster stage

 

 

2024 Production Updates and Seasonal Outlook for NS_ 6th Blight Line Post_ May 10

Friday, May 10, 2024

 

Hi, everyone

We are looking to have some decent spraying weather in the next few days. The next potential long wet period could be mid-next week. Before the weekend, I want to share these quick updates.

Have a good spraying weekend!

Hugh

 

 

GDD Updates_ May 10, 2024

 


 

Figure 1. GDD Summary, May 10, 2024


Wild Blueberry Sprout and Crop Development Stages


Sprout fields:

Growers are encouraged to complete pre-emergence herbicide applications as soon as possible.


New blueberry leaf buds are starting to form and in some early areas/fields, leaves are unfolding. The plant emergence is still in the early stages (0-5%) which indicates the safe window to spray herbicides is getting shorty and it is getting riskier as more buds and leaves are formed in sprout fields.

 


Crop fields:

Please refer to Table 1 for regional F2 % predictions.

In the last few days, many areas in NS experienced a 12-24 wet period which created potentially favorable conditions for apothecia* to re-active and produce disease spores. Under 10 °C conditions, those structures only need about 6 hours to get activated and produce spores. Today’s conditions seemed to be favorable and potential infection risk is expected in crop fields with a high percentage of opening fruit buds.

 

*Apotheica is a small cup-shaped and spore-bearing structure that is produced by overwintering mummy berries on the ground. 

 

If you didn’t get a chance to spray crop fields with fungicide before this wet period, you can still put something on after the fields are dry. Most of Monilinia Blight products would have around 48-72 hours back action depending on what you use. If you can spray successfully in this time frame, the risk of getting a blight infection will be lower.

 

Air temperature and wetness duration are two critical factors in determining the severity of Monilinia infection periods. Please refer to the below figure and your local weather conditions to decide if a fungicide application is needed and when will you need to spray.

 

Figure 2. Severity Rating of Monilinia Infection Periods


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

 

 

South West Nova Scotia

 

Queens County

>40%- April 24

 

 

Hants County

>40%- April 29

 

 

Cumberland County

 

West Advocate

>40%- April 29

Kikhill

>40%- April 29

Halfway River

>40%- April 29

 

 

Colchester County

 

Belmont

68% F2- May 10

Murray Siding

88% F2- May 10

Camden

40% F2- May 10

 

 

Halifax Regional Municipality

>40%- May 8

 

 

Guysborough County

30% F2- May 10

 

 

Pictou and Antigonish County

 

Blue Mt. (NSW017)

54% F2- May 10

Moose River (NSW061)

41% F2- May 10

 

 

Cape Breton

10-15% F2- May 10

 

 

2024 Production Updates and Seasonal Outlook for NS_ 5th Blight Line Post_ May 8

Wednesday, May 8, 2024


Monilinia Blight Infection Risk for most of Cumberland and Colchester fields

 

This GDD summary is from May 6, 2024 (Figure 1). At this point, most crop fields in Cumberland and Colchester are at risk for Monilinia Blight infection, except for higher ground and cooler areas. Crop fields in Dean and Musquodoboit areas are also susceptible to blight and a fungicide application should be considered according to the latest weather conditions. If your area and fields are above 40-50% F2, fungicide application should be conducted before a wet period (Table 1). According to the weather forecast, from Wednesday evening to Friday morning, it will be wet across the province (Figure 2) and will bring several infection periods.

It is still a little early for fields in Guysborough, Antigonish, Pictou, and Cape Breton to spray the Monilinia Blight fungicide at this time.

 

Here is a summary of the most up-to-date GDD from 17 weather stations in wild blueberry fields.


 

Figure 1. GDD Summary, May 6, 2024


Figure 2. NS Weather Forecast (CBC). A wet period starting Wednesday evening until Friday morning.

 

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

 

 

South West Nova Scotia

 

Queens County

>40%- April 24

 

 

Hants County

>40%- April 29

 

 

Cumberland County

 

West Advocate

>40%- April 29

Kikhill

>40%- April 29

Halfway River

>40%- April 29

 

 

 

 

 

 

Colchester County

 

Belmont

>40%- May 8

Murray Siding

45% F2- May 2

Camden

31% F2- May 8

 

 

Halifax Regional Municipality

>40%- May 8

 

 

Guysborough County

20% F2- May 8

 

 

Pictou and Antigonish County

20-25% F2- May 8

 

 

Cape Breton

10% F2- May 8

 

 

A close up of sticks

Description automatically generatedSprout fields pre-emergence herbicide applications

Growers should finish sprout fields’ herbicide application as soon as possible. Plant emergences were observed in sprout fields (Figure 3).

 

Figure 3. Wild Blueberry Plant Emergence in Sprout Fields (Colchester)

 

 

 

2024 Production Updates and Seasonal Outlook for NS_ 4th Blight Line Post_ May 3

Friday, May 3, 2024

2024 Production Updates and Seasonal Outlook for NS_ 4th Blight Line Post_ May 3

 

Hi, everyone. We are officially in a Monilinia Blight season for most of the central early/low-ground fields. From the weather forecast, we are going to have some continuously double digital air temperatures in the next 7-14 days which are the peak and the most susceptible timing of the blight in wild blueberry crop fields. We will highlight Monilinia Blight management in today’s post, but I want to remind growers to monitor crop fields and local weather conditions very closely in the next two weeks.

Wild blueberry growers across the province can start pre-emergence herbicide application now. In some early areas, it is getting too late. Please apply herbicides accordingly and sooner.

-Hugh

 

Growing Degree Days (GDD) Summary

This year, we are going to report GDDs from 17 stations (see Figure 2) which cover the major wild blueberry production regions in NS. There are different ways to obtain GDDs by choosing the station you like. To learn how to obtain GDDs, please read this blog post: http://www.novascotiawildblueberryblog.com/2023/04/2023-wild-blueberry-pest-guide-new.html.

*Please note that Earltown weather station is out of service so we can’t report the latest GDD from this station. We will resume once we see it back online.

Figure 1. 17 Wild Blueberry Stations for GDD updates


Here is a summary of the most up-to-date GDD from 17 weather stations in wild blueberry fields.

Figure 3. GDD Summary, May 2, 2024

 

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 2. 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

 

 

South West Nova Scotia

 

Queens County

>40%- April 24

 

 

Hants County

>40%- April 29

 

 

Cumberland County

 

West Advocate

>40%- April 29

Kikhill

>40%- April 29

Halfway River

>40%- April 29

 

 

 

 

 

 

Colchester County

 

Belmont

33% F2- May 2

Murray Siding

45% F2- May 2

Camden

20% F2- May 2

 

 

Halifax Regional Municipality

 

Middle Musquodoboit

30-40% F2

Dean

30-40% F2

 

 

Guysborough County

5-10% F2- May 3

 

 

Pictou and Antigonish County

5-10% F2- May 3

 

 

Cape Breton

0% F2- May 3

 

 

Monilinia Blight Management in Wild Blueberry Production

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 divide 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.

For monilinia to infect blueberry plants, there should be 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.

Resources:

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