Hi Dear
Readers!
Spring is
definitely upon us, and I hope you are enjoying the warmer weather. Thank you
for attending the most recent webinars. They are posted on the Perennia You
Tube channel along with the PDFs from each session. The links are provided
below. You are welcome to refer to all the content at your convenience.
There were a
couple of questions about critical temperature that came up at the Spring Frost
webinar session that I would like to address as I feel they are worth
additional the attention.
A question
was asked about how long tissue needs to be exposed to freezing temperatures for injury to occur. Some literature suggested 30 minutes or less below 0 degrees, but this is highly variable. There are many factors that influence tissue
injury. We know that ambient air temperature
at 0˚ C or cooler may last for several hours. The longer the
exposure to those temperatures, the higher the likelihood that the buds or
leaves (actively growing tissue) may be damaged. It is advisable to have a plan
in place to mitigate potential frost injury as we are never fully sure how long
the cold event may last.
If your site is prone to frost and you have the ability to utilize wind machines, you should start them before temperature reaches 0˚ C. To have the machines effectively utilize an inversion layer, most growers would start the machine at 3 or 4 ˚ C.
The idea is to mitigate the threat instead of reacting to
it once it begins. Machines do not have
to run once the ambient air temperatures reach above freezing. In most cases
this is around 90 minutes after sunrise. The coldest time of night is actually
just before sunrise, so keep that in mind. You are likely to have a sleepless
night, but accurately monitoring the air temperature as it declines then rises
in the morning makes for the most effective use of wind machines.
As always,
we encourage you to keep records of cold events, their duration, severity, vine
growth stage, cultivar differences, amount of injury observed and if there are damage differences based
on location in your vineyard. These will inform your
viticultural decisions for the future.
News to
share:
· We have started to document vine
growth stages at several sites and will continue to do for the foreseeable
future. Gathering this data will provide us with a historical record and become
an additional tool with which to provide sound advice for the advancement of
the industry.
· Dr. Kevin Ker will be visiting in June, so we will be on the road again meeting many more growers.
Please refer to the following links for the recorded
presentations and a PDF format of the slides.
https://www.perennia.ca/wp-content/uploads/2024/05/Grape-Pests-Scouting-Basics.pdf
https://www.perennia.ca/wp-content/uploads/2024/05/Spring-Frost-and-Freeze-Damage.pdf
Thank you for your time, and enjoy the week ahead.
Cheers!
Katarina
Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722
Cell 902-599-1390
