The Atlantic Tech Transfer Team for Apiculture has been conducting research related to Varroa mite management since 2017. This year the ATTTA team decided to conduct research in the form of a regional Varroa mite survey. This survey is important to the Maritime beekeeping industry as it will assess the efficacy of mite management across our region. Read this week’s blog for a mid-season summary of the results to date.
ATTTA Varroa Mite Survey Mid-Season Summary
This year
ATTTA has been conducting a regional Varroa mite survey involving 18 different
beekeepers from New Brunswick, Nova Scotia and Prince Edward Island. These
beekeepers represent a significant portion of Maritime beekeeping operations. The
survey is intended to broadly sample across the Maritime region. Those who
participate have been asked to provide ATTTA with 3 samples of approximately
300 honey bees 3 times throughout this beekeeping season (prior to pollination,
after pollination and late season). Samples were only taken from commercial
beekeepers who use their colonies for wild blueberry pollination. The survey
has several main goals, including determine Varroa mite levels across the
region at three important time points during the current season; collect Varroa
mites for miticide efficacy testing; establish temporal measurements for annual
comparison of Varroa burden for the Maritime region; and create a stored bank
of samples for possible future testing (e.g. tracheal mite).
After
conducting various testing, ATTTA informs participants on the health of their
bees (Varroa mite load and efficacy of mite treatments). This blog provides a summary of trial 1 and trial
2 to date, which occurred between May 11, 2024 to June 27, 2024 and July 3,
2024 to July 31, 2024 respectively.
To date,
ATTTA has received samples from 20 apiaries, 66 colonies, and processed a total
of 105 samples. For details on Varroa mite load, which is determined using an
alcohol wash, please refer to Table 1.
Table 1.
Summary of results for ATTTA Varroa Mite Survey between May 11, 2024 and July
31, 2024.
|
Sampling Period |
Colonies Positive for
Varroa Mites |
Colonies Above the
Economic Threshold Requiring Treatment |
|
Trial 1 (Pre-Pollination) |
3 /42 (7%) |
1 / 42 (2%) |
|
Trail 2 (Post
Pollination)
|
18 / 63 (29%) |
4 / 63 (6%) |
|
Overall Sampling
|
21 /105 (20%) |
5 / 105 (5%) |
The number
of colonies with detectable Varroa mites from an alcohol wash increased by 22%
from early-season (pre-pollination) to mid-season (post-pollination) (Table 1).
The number of colonies above the economic threshold increased by 4%
from early-season (pre-pollination) to mid-season (post-pollination) (Table 1).
It is important to understand that the population of Varroa mites
increases throughout the beekeeping season, which is reflected by the increase
in mites sampled between May/June (trial 1) and July (trial 2). The results of
this survey support the fact that the population of mites increases as the
beekeeping season progresses. This makes early spring monitoring and treatment
for Varroa mites crucial, because the population can quickly get well beyond
the economic threshold if waiting until the fall to treat colonies again.
Beekeepers need to be vigilant with monitoring for mites each month to ensure
that colonies will be strong and healthy by the time winter preparations occur.
If a beekeeper is seeing mites during the early part of the beekeeping season,
then they should be prepared to provide treatment by fall. There is also the
potential that the number of mites will exceed the economic threshold prior to
the fall if colonies are not treated in the spring, in which case a mid-season
knock down treatment may be indicated to keep the mite population under control
until fall treatments can occur.
With monthly monitoring, treatment is only indicated when the mite
population is at or above the economic threshold. Beekeepers should keep in
mind that current economic thresholds are conservative, and if they have
questions about treatment options and/or when treatment is indicated please
reach out to the ATTTA team. In recent years the beekeeping season within the
Maritimes has been growing longer, which presents a greater concern for
managing Varroa mites.
Overall, the results of the survey to date indicate that beekeepers are
doing a good job at managing mites in the Maritimes, and that current
treatments continue to be effective within our region.
The ATTTA
team will be conducting the final trial for the survey in early September.
Additionally, the team has plans to conduct testing on the efficacy of amitraz
(active ingredient in Apivar) later this season using mites collected from
Maritime beekeepers.
We would
like to thank all the Maritime beekeepers who have participated in the survey
to date. The research ATTTA does is dependent on the involvement of beekeepers,
and in turn we aim to provide regionally specific information for the industry.
Connecting with ATTTA Specialists
If you’d like to connect with ATTTA specialists or learn more about our program, you can:
visit our website at https://www.perennia.ca/portfolio-items/honey-bees/
Email abyers@perennia.ca