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.




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.