sideliner and backyard beekeepers
as well as stationary and migratory.
The survey is open for April of
every year and the preliminary loss
results of 2017-18 are just in.
This year, 4,794 beekeepers,
collectively managing 175,923
colonies in October 2017, provided
validated survey responses. This
represents 6.6 percent of the
nation’s estimated 2.67 million
colonies (USDA NASS Honey
Report 2018).
During the winter 2017-18 season
(October 1, 2017 – April 1, 2018), an
estimated 30.7 percent of managed
colonies in the United States were
lost (Fig. 1). This represents an
increase of 9.5 percentage points
compared to last year, and an
increase of 2.8 percentage points
compared to the 10-year average
total winter loss rate of 27.9
percent.
Similar to previous years, Backyard
Beekeepers lost more colonies
during winter (46.3 percent)
compared to Sideline (38.0 percent)
or Commercial (26.4 percent)
Beekeepers. Backyard, Sideline,
and Commercial Beekeepers are
defined as those managing 50 or
fewer, 51 – 500, and 501 or more,
colonies, respectively.
Interestingly, the self-reported level
of acceptable winter loss increased
from 20.6 percent to 18.7 percent
this last year. Whether this is due
to beekeepers becoming more
pessimistic (or realistic) is too soon
to tell; however, 69 percent of
participating beekeepers lost more
than was deemed acceptable.
During the summer 2017 season
(April 1 – October 1, 2017), an
estimated 17.1 percent of managed
colonies were lost in the country.
This level is on par with the summer
loss estimate of the previous year.
For the entire period (April 1, 2017
– April 1, 2018), U.S. beekeepers
lost an estimated 40.1 percent of
managed honey bee colonies; this
is an intermediate annual rate of
loss recorded since 2010-11, the
year that these data began to be
recorded.
How do we explain these higher
losses this year
?
It is important
to know that the Loss Survey’s
objective is to document trends,
not determine their cause(s). Also,
there are a lot of different factors
that affect honey bee health, and
ultimately, colony loss. But we
venture a few opinions.
In the past, we have looked at
the Varroa mite infestation loads
in the fall from an independent
National Survey (APHIS National
Honey Bee Disease Survey) and
noticed an association with colony
mortality in the winter at the state
level. States with higher Varroa
loads in September also presented
higher mortalities that winter. We
Fig 1. Total winter colony loss rate in the United States across years of the Bee Informed
Partnership’s National Honey Bee Colony Loss Survey (yellow bars: October 1 – April 1).
Total annual loss estimates (orange bars) include total winter and summer (April 1 –
October 1) losses; the latter has been estimated since 2010-11 only. The acceptable winter
loss rate (grey bars) is the average percentage of acceptable winter colony loss declared by
the survey participants in each year of the survey.
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