Be Aware of Phytochemical Burn

Sunday, June 29, 2025

 Hello Dear Growers, and Happy long Weekend!

As we rush through flowering (again, seems to be happening overnight) due to the recent heatwave, we have to be mindful when spraying.

We have had several calls this week - with growers worried about what looked like disease spreading through their vineyards. 

I advise anyone who is unsure to send photos, texts about what they are seeing. Indeed, some chemical burn can look like Anthracnose and even Black Rot. 

Here are some examples of what we have been seeing the last couple of weeks: 


  






These are examples of young vines and established ones. What we see here are various burn marks, but also distorted and "waxy" looking, young leaves with chlorosis. 

The symptoms may look like a myriad of things-especially when a disease is just getting established, so it important to get a second opinion if you are unsure of the cause.  

Why does this happen? Is it just because it is hot?

Chemical burn can happen for several reasons:

-Cultivar Sensitivity. Some Hybrids are more sensitive to sulphur than others. Meanwhile, vinifera are not sensitive to sulphur.

-Spraying mere water in hot weather can cause leaf burn.

-  Spraying a mix of products during warm weather.

- Spraying a mix of products in addition to nutrients. (Temperature may be irrelevant).

-Spraying products that are not compatible with each other. 

Sometimes, it is not one product that is causing the problem, but the totality of  products sprayed together or in close succession to each other. 

I advise you to follow the labels closely. 

This is especially important when spraying nutrients in close succession to the phyto products. The labels may not state if the products are compatible for spraying simultaneously. If you are unsure, I advise you to text, email or call me prior to spraying. 

PHENOLOGY

Osceola Muscat:  Past flowering and into fruit set. 

New York Muscat: No flowering

L'Acadie: flowering starting. About 2%.

Petit Pearl: No flowering

Marquette: 80% Through flowering.

Baco Noir: 90% Through flowering.

Lucy K: 90% Through flowering.

Triomphe de Alsace: 85% through fruit set.

Frontenac Blanc and Gris: 90% through flowering and starting fruit set.

Chardonnay, Pinot Noir and other vinifera: No flowering.


If you have any pictures, anything that is worrying you in your vines, do contact me. I hope you had a lovely weekend and Happy Canada Day!

Cheers!

Katarina

 

Katarina Vucic P.Ag; MSc; DipWSET

Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722

Cell 902-599-1390




Pre-Bloom- A Crucial Time for Disease Management

Friday, June 20, 2025

 Happy Friday Dear Growers!

I hope you have all had a good week. I'll dive right into upcoming events, followed by the phenology report and scouting and pest management reminders.

In less than a month from now, Dr. Kevin Ker will be here for a masterclass in Canopy Management. Please see the flyer below. The sessions are IDENTICAL, held in two different locations. Please attend the session closest to you. Note the addresses on the flyer below and sign up using the link below:

https://www.perennia.ca/eventer/sunlight-shoots-sugar-mastering-canopy-management-for-top-quality-wine-grape-production/

The second July event is a collaboration with Cavendish, Scotian Gold, and Blomidon Winery, focused on showcasing drone and soil mapping technologies. We'll demonstrate a range of precision agriculture tools, discuss the data they generate, their practical applications, pricing, and cost-effective acquisition options. Vendors will also be available on-site to answer any questions. The Tech session is open to all growers-regardless of commodity.

Please see the flyer here and register using the link below:


Smart Farming in Action: Using Precision Ag and Drone Technology for Site-Specific Field Management – Perennia

Early Season Canopy and Disease Management: It's the time of year for shoot thinning, tucking and soon enough- cluster thinning.

During the prebloom period, shoot growth alone is insufficient. In most trellis, training, and pruning systems, shoots must also be deliberately spaced and positioned to optimize light interception by the leaf surface, enhance air circulation and light penetration within the fruiting zone. 

Improved airflow through the canopy helps:

-Reduce humidity levels around clusters.

-Lowers the risk of fungal diseases like black rot, botrytis, and downy mildew. 

-Allow for better air movement also speeds up drying after rain or dew, minimizing conditions favorable to disease development.

-Supports more uniform spray coverage and penetration, making disease control treatments more effective. 

For further information, please see the latest fact sheet published on the "Grapes" page of the Perennia website: 

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.perennia.ca/wp-content/uploads/2025/06/Grapevine-Canopy-Management-Shoot-ThinningV4.pdf

Phenology Report:

What a huge change from one week to the next! Last week, I saw no inflorescence, and this week, each variety's shoots have doubled in size and inflorescences immerged. 

All the varieties are at the pre-flowering stage. This is Osceola Muscat from Wednesday afternoon:

Figure 1. The florets on inflorescence have separated. 

The pre-bloom stage indicates the beginning of the critical stage where pest management is crucial. 

The period of time from immediate pre-bloom to 5-weeks post-bloom is when disease pathogens can cause significant damage. Do make sure you are protected against Downy Mildew, Phomopsis and Black Rot. 

As always, do keep an eye out for the beginnings of flowering and note them down for your sites and varieties. 

Thank you all for your time this week, and I hope you all have a good weekend.
I look forward to seeing you at both in-person events.

Cheers!
Katarina

Katarina Vucic P.Ag; MSc; DipWSET

Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722

Cell 902-599-1390

 

www.perennia.ca