New Brunswick 2020 Wild Blueberry Crop Update

Thursday 17 December 2020

This week’s blog brings you the final update on our regions 2020 wild blueberry crop.  Wild blueberry producers in New Brunswick had some challenges this season.  The NB provincial wild blueberry expert has supplied a report with all the details which you can read below.

The limited chemical miticide options for beekeepers are a concern.  We are seeing very good efficacy with Apivar® (active ingredient: Amitraz; chemical group: Formamidine) but the worry is that mites may develop widespread resistance.  New and exciting research, being done by a team from Alberta, is working to find alternative drug treatments for Varroa control.

New Brunswick 2020 Wild Blueberry Crop Update

New Brunswick wild blueberry growers harvested an estimated 28 to 29 M lbs, compared to the 2019 crop of 67.3 M lbs and the 2018 crop of 53.5 M lbs, when similar fields were harvested. An estimated 16,500 acres were harvested in 2020.  The decrease in total production is due partially to a frost in the spring and dry conditions during the summer of 2020. About 2/3 of the provincial yield is harvested from the Northeast region. An estimated 35,000 honey bee hives were used for blueberry pollination. Bumble bees and Alfalfa leaf cutter bees (ALB) were also used to supplement pollination.  There was only minimal winter injury in some regions. Monilinia blight pressure was low, and most fields had few symptoms. The early days of bloom were good, with many good to excellent days for pollination. The weather conditions were dry, and some fields were showing symptoms of stress. Despite the dry conditions, fruit was present on the plants, but berry size was small and weights were low. This resulted in poor yields in many fields. Yields for some fields ranged from complete loss to adequate, compared to previous crops of 4,000 lbs/acre or better.

Michel Melanson, Environmental Services and Crop Specialist Unit (Blueberry and Apiculture), NB Agriculture, Aquaculture and Fisheries.

Potential New Varroacides for Beekeepers: Fenazaquin and Etoxazole show promise!

An effective Varroacide must have high toxicity for the mites and a low toxicity for honey bees. A team of researchers in Alberta has just published a report on work done to determine the potential of a range of chemical treatments for Varroa mites.  They examined how effectively the treatments killed Varroa, balanced against how these substances were tolerated by the honey bees.  The trial tested 16 active ingredients and 10 formulated products.  Two active ingredients, fenazaquin (chemical class: quinazoline) and etoxazole (chemical class: oxazoline) both proved promising for control of Varroa mites and are seemingly safe for honey bees.  A number of other compounds tested were effective as miticides but further work is needed to examine honey bee tolerance.

The long-term use of any one chemical, or family of chemicals, will result in mites developing resistance.  Ongoing control of Varroa mites will require novel chemical treatments, careful use of current treatments, and an IPM plan.  Apivar® has been used by Canadian beekeepers to manage Varroa mites for over 10 years and is generally, still an effective product.  In spite of Apivar’s continuing efficacy, it is reassuring that new, possible replacements are being investigated.

It must be noted that this is preliminary work to determine the usefulness of these miticides and they are not currently licensed for use by beekeepers.  Further work, both inside and outside of the lab, is needed and we optimistically look forward to hearing more as these research studies progress.

Full article: Bahreini, R., Nasr, M., Docherty, C. et al. Evaluation of potential miticide toxicity toVarroa destructor and honey bees, Apis mellifera, under laboratory conditions. Sci Rep 10, 21529 (2020).

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