2023 Updates and Seasonal Outlook for NS_ May 31_ frost& weather updates, botrytis management and pollination

Wednesday, May 31, 2023

 

This post will focus on frost and weather updates, botrytis management and pollination.

 

Frost and Weather Updates

 

May 30 Frost Damage Update:

Regarding Tuesday’s (May 30) morning’s frost, I made a summary of minimal temperatures from wild blueberry weather stations: http://www.novascotiawildblueberryblog.com/2023/05/post-frost-event-summary-may-30-2023.html.

 

I checked fields in Pictou (Blue Mt., Moose River and Blanchard Road) where stations reported below -2 c for about 6-7 hours. Luckily, all fields in those areas were still in the pre-bloom stage with limited open blooms. I don’t think growers should concern about this frost.

 

The next potential frost is going to be around the full moon (June 4) and here are some words from weather experts:

 

“The weather pattern is most likely going to be a cool and wet one this weekend – all models are predicting it actually.  This means cool but overcast and light to moderate NE winds.  Temps would likely be in the 5 to 10C range for several days if this pattern ‘stalls’ which is the current indication.  So that’s a saving grace as long as the skies don’t clear out during the spell of weather.  Even if they did clear out for a short period over the weekend, it could be brief and the ground should already have moistened up with showers/drizzle.”- from ECCC.

 

Most mainland fields will be in full bloom or in a high percentage of bloom stage (20% and above) which puts those fields at a greater risk of frost damage. If you are thinking to apply fungicides (Pristine and Merivon), the most effective window would be 12-24 hours before. Based on this, the time frame (regardless of the rain we might get this weekend) is Friday to Saturday morning.

 

Weather Update:

 

Perennia’s Tree Fruit Specialist, Michelle Cortens, wrote a summary about this year’s weather, including GDD and precipitation. https://www.nstreefruitblog.com/2023/05/orchard-outlook-newsletter-vol-23-no-7.html#h1. This is a very nice information for you as well. Thanks, Michelle!

 

Content from Perennia’s Tree Fruit Blog:

 

 

2023 Degree Day Accumulations

 

Cumulative degree days continue to be slightly behind the 5- and 10-year averages for plant and insect development (Figure 1). The lack of heat equates to plant growth being about 2 to 3 days behind average. The average temperature for May is 10.2°C compared to the 10-year average of 11.2°C. 

 



Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to May 29 for the past 17 seasons. Provided by Jeff Franklin (AAFC).

·                Approximately 8% less plant development heat units compared to the 5-year average, and 9% less compared to the 10-year average.

·                Approximately 22% less plant development heat units compared to 2022, and 21% less compared with 2021.

·                Approximately 10% less insect development heat units compared to the 5-year average, and 15% less compared to the 10-year average.

 

 

2023 Precipitation

 

The Kentville weather station has recorded less than half the monthly average rainfall at 31 mm out of 74 mm. Jeff Franklin assembled the total precipitation for the months of April and May, for Kentville, over the last 111 years and sorted from lowest to highest. The 10 driest years are shown in Table 1 and 2023 ranks as the 5th driest year.

Table 1: Total precipitation for the months of April and May in Kentville over the last 111 years, showing the 10 driest years. Provided by Jeff Franklin (AAFC).



 

 

Botrytis Management

If you are in areas where typically more prone to botrytis infection, such as coastal areas, and 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.

 

Pollination

 

Overwinter beehive health: last I checked with some beekeepers, the winter losses for NS bee hives were around 15-20% which is still under an acceptable range. Bees survived over the winter look very good and they gain weight very fast. Up to this point, a couple of beekeepers are still feeling there is enough nectar flow with the rain we will get next week, it should be a very positive sign for pollination.

 

 

Post-Frost Event Summary- May 30, 2023

Tuesday, May 30, 2023

 Post-Frost Event Summary- May 30, 2023

  

Good morning,

 

It looks like a safe morning for most of the fields in the province with concerns on some fields in Pictou (3 weather stations and nearby fields to watch). I am not as worried as last week’s frost but there are a few fields near those areas worthwhile to be checked.

If you have any feedback or things to share, please text or call Hugh Lyu, at 902-890-0472; or hlyu@perennia.ca. Thank you!

I would suggest growers who have fields near those areas/weather stations check their fields and assess potential frost damage, especially fields in Pictou.

 

Counties and Weather Stations

Lowest Temperature Observed (Celsius)

Duration (hrs) of temperatures below -2 C

Colchester

Belmont (NSW087 and NSW037)

-1.3

0

Upper Kemptown (NSW022)

-2.1

0

 

 

 

Cumberland

North Harrison Settlement (NSW065)

 

-1.4

0

Salt Springs (NSW077)

 

-1.8

0

Pictou

Dalhousie (NSW074)

-2

2

 

Four Mile Brook (NSW021)

-1.6

0

Hazel Glen (NSW086)

-1.4

0

New Gairloch (NSW019)

-1.2

0

Sunny Brae (NSW058)

-2.6

1

Blanchard Road (NSW059)

-2.6

6

Blue Mountain (NSW060)

-2.8

6

Moose River (NSW061)

-3.7

7

Fields near Blanchard Road, Blue Mt. and Moose River are around 10% bloom which puts those fields at a lower risk but damage would still occur to any open flowers. 


 

 

Antigonish

 

 

 

South Shore Counties

 

 

 

Cape Breton

Keppoch (NSW029)

 

-2.4

1

Hants and Halifax Regional Municipality (HRM)

Chaplin (NSW071)

 

-2.6

1

Dean (NSW069)

 

-1.5

0

Woodside (NSW070)

-1.2

0

 

 

 

 Please click the below images to see a bigger and clear picture of minimal temperatures from weather stations: 

 



 


 

 



2023 Updates and Seasonal Outlook for NS_ May 29 Frost Advisory for Eastern and Northern Mainland Nova Scotia and Cape Breton

Monday, May 29, 2023


Frost Advisory for Eastern and Northern Mainland Nova Scotia and Cape Breton

(Expected on early Tuesday morning, May 30)

 

 

Hi, everyone

 

There is a frost advisory issued for Eastern and Northern Mainland Nova Scotia (Figure 1). The forecasted minimum temperatures are from -2 c to + 4 c.

More information about frost damage in wild blueberry production? Please check last week’s blog post: http://www.novascotiawildblueberryblog.com/2023/05/2023-updates-and-seasonal-outlook-for_25.html.

On Tuesday morning (May 30), I will give an update on overnight and early morning minimum temperatures and durations from wild blueberry weather stations.

Given the crop stages in the frost-affected area, this frost could be concerning for crop fields with a good percentage of open bloom (15-30% and above) in those areas.

Fields in Pictou, Antigonish and Cape Breton are still in the pre-bloom stage with a low percentage of bloom (5%) which put those fields at a lower risk of this frost event, but cold temperatures below -2.2 c could still cause damage to any open flowers.

 



Pre-Bloom- relatively safe from frost and low temperatures. Those pre-blooms are safe at -5 c and above.

 

 


Open-bloom, prone to frost and low temperatures damage. -2.2 C is a critical point for those open blooms.

 

Fields in Cumberland and Colchester are at a greater risk of this frost event due to the % of bloom in those areas being higher (15-20% and above). If you are using one of the stations close to your fields, please watch and check your GDDs. A station with around and above 400 GDD put fields nearby at greater risk. From this year’s GDD and bloom % (in progress) and field observation, fields near a station with above 400 GDD show that the % of bloom is around 15-20%. Please see Figure 2- GDD summary.

 



 

Figure 1. Frost Advisories for parts of Nova Scotia

 

 

 

 

Growing Degree Days (GDD) Summary and Plant Development Updates


Figure 2. GDD Summary, May 28, 2023



What Can You Do?


1.      There is nothing you can do to change mother nature’s mind but we still have a few recommendations for you to consider.

2.      Check your local temperatures from close wild blueberry weather stations or any source you like. Knowing the lowest temperatures and the duration of the event is beneficial as this can help you to pre-determined the level of damage from frost. https://www.capebretonweather.ca/

3.      You would be able to see symptoms on open blooms and their petals from frost damage a few hours after. Normally, you would be able to see initial signs on petals on the same day but in terms of potential yield reduction, you have to wait until green fruits are set.


Figure 3. Frost damage on wild blueberry flowers

 

4.      Considering other frost-protection methods.


a.       I don’t think there is much you can do. Some methods we know are burning, copper and zinc, and applying irrigation water, but they are not practical in our region and this crop.

b.      Some fungicides we use during this time of the year offer frost protection features besides their regular disease control function. Pristine (pyraclostrobin and boscalid) and Merivon (Pyraclostrobin and fluxapyroxad) may help with frost protection. It is recommended that those products are put on 12-24 hours before a forecasted frost event.

*When I checked weather stations, the cold temperatures normally start around 3 AM. I hope this is helpful to time your spraying.

** I don’t expect you to apply those fungicides today because of the short notice and high wind, but this would come in handy when any future frost events are forecasted.

 

 

I hope we don’t get a bad frost!

 

Hugh

2023 Updates and Seasonal Outlook for NS_ 10th Blight Line Post_ May 25

Thursday, May 25, 2023

 2023 Updates and Seasonal Outlook for NS_ 10th Blight Line Post_ May 25

 

Advance Notice: this is the 2023 season’s last blight line post. After that, I will still give updates and provide seasonal management recommendations through this blog. In the next little while, you are going to hear me talking a lot about frost, pollination, botrytis blight and weed management.

 

Growing Degree Days (GDD) Summary and Plant Development Updates



Figure 1. GDD Summary, May 24, 2023

 

Sprout fields:

I hope no one is out there applying pre-emergence herbicides (Chikara, Ignite, Spartan, Velpar etc.) in your sprout fields after today. Most of the fields in the mainland are at and above 50% plant emergence. Now, you can start thinking about fertilizer applications and a few post-emergence herbicides (Callisto, Venture L, and Poast Ultra) to control goldenrods and grasses.

If you are thinking about Option+ Prism, now it is time to apply those products before fescues produce seed heads. Fescues should stop growing after Option is put on so don’t let them grow too far and produce seeds.

Crop fields:

Most of the central fields should be over with this year’s monilinia infection risk after today and tomorrow’s drizzles. The plant stage of most fields is at pre-bloom with 5-10% bloom. Some early fields in Cumberland are around 30-40% the most. Those fields with a bloom % of 0-40 or above could be prone to frost damage. Some products, like Luna Tranquillity and Merivon, should provide frost protection to blueberry blooms during a frost event. This would be something to consider prior to a forecasted prost event, given that those are also botrytis blossom blight industry-standard products.



Pre-Bloom

 

 

Some late fields in Pictou and Antigonish and fields in Cape Breton still have another week to worry about the infection risk. Please consider and apply products as needed.

 

 

I know I share this already but this resource is important during this time of the year when we are facing challenges from diseases and mother nature. I will share more information about frost and its’ risk to blueberry blooms and potential yield reduction risk, why and how.

 

Frost Damage? Disease Infection? Monilinia VS Botrytis?

 

Many growers are wondering how to tell the differences between frost damage and disease infection on leaves and flowers. The UMaine Wild Blueberry Extension team produced a very nice factsheet and this is a good one to print and keep handy.



 

Here is a factsheet about frost events produced in 2018 when we faced a big frost event in that year. I am worrying about the full moon (June 4, Sunday) when we might get a frost event and at that time, most of the fields are in mid-bloom which will put all our crop fields and blooms at risk.







Post-Frost Event Summary- May 23, 2023_ -from 55 weather stations in wild blueberry fields

Tuesday, May 23, 2023

 Dear growers,

 

The following stations reported below -2 c during this morning’s frost event which is a concerning point this time of the year for many fields because of opening flowers.

 

If you have fields near those stations I listed below, ESPECIALLY those stations highlighted in red where temperatures were low and the duration was also more than 3 hours, please check you fields! 

 

If you have any feedback or things to share, please text or call Hugh Lyu, at 902-890-0472; or hlyu@perennia.ca. Thank you!

 

Counties and Weather Stations

Lowest Temperature Observed (Celsius)

Duration (hrs) of temperatures below -2 C

Colchester

Glenholme (NSW001)

 

-3.1



4

Murray Siding (NSW002)

 

-2.6

3



Keble (NSW020)

 

-4.3

6

Upper Kemptown (NSW022)

 

-2.3

1

Debert (NSW036)

 

-2.7

1

Belmont (NSW037)

 

-3.6

4

Staples Brook (NSW038)

 

-2.1

1

Belmont (NSW087)

 

-3.7

4

 

 

 

Cumberland

Oxford (NSW004)

-2.7

3

Oxford (NSW005)

 

-3.2

4

North Harrison Settlement (NSW065)

 

-3

4

South Harrison Settlement (NSW066)

 

-2.3

1

New Canaan Bottom (NSW073)

 

-2.1

2

Wentworth (NSW076)

 

-2.8

4

Salt Springs (NSW077)

 

-2.7

5

East Mapleton (NSW078)

 

-2.2

1

Yorke Settlement (NSW080)

 

-1.9

2

Pictou

Four Mile Brook (NSW021)

 

-3.5

6

Hazel Glen (NSW086)

 

-4.4

6

 

 

 

Antigonish

 

 

 

South Shore Counties

 

 

 

Cape Breton

 

 

 

Hants and Halifax Regional Municipality (HRM)

Dean (NSW069)

 

-3.6

2

Woodside (NSW070)

 

-2.2

2

 

 

Mainly weather stations in Cumberland and some in Colchester:











 

Weather stations in Colchester, Pictou, Antigonish and Cape Breton: