All: This just came across my email from the MD IPM Weekly report. Note however, that there may be possible confusion between the golden rain tree
Message 1 of 1
, Sep 9, 2011
This just came across my email from
the MD IPM Weekly report.
Note however, that there may be possible
confusion between the golden rain tree (Koelreuteria paniculata)
and the golden chain tree (Laburnum). The later (according
to Wikipedia) is highly toxic in all parts, while the former has edible
seeds...in any case, the observations below bear repeating so that we can
all keep watch for problems. I believe that in Maryland that
Koelreuteria paniculata is
more common and I think of it as incredibly attractive to Megachile
Juang-Horng ‘JC’ Chong, Ph.D., Clemson
University, sent out an interesting inquiry about bees being
killed by a golden raintree. Here
are his question/observations:
Did anyone ever observe a large
number of dead bumblebees associated with goldenrain tree? A good friend, who is also the executive director
of a local botanical garden, informed me that the goldenrain tree/Chinese flame tree (Koelreuteria bipinnata)
in the garden was in full bloom and killing bees. Last Friday, we counted about 48 dead bumblebees (species
not identified) under the tree. At the time, hundreds of honeybees, bumblebees and other native bees were visiting
the flowers; only bumblebees were found dead. Ignorant of the effects of goldenrain trees on bees and
suspecting that the hive and bees might be poisoned before visiting the
flowers, I suggested to my friend to clean
up the ground and see what happens next. The ground was cleared on Tuesday. Dead bumblebees were found on the
ground on Tuesday afternoon (20) and Wednesday (42). The trees have never been treated with any insecticides,
systemic or otherwise. I have not heard of a similar occurrence. I cannot confirm if something similar
is happening in the neighborhood because those may be the only two goldenrain trees within a radius
of 10 miles.
David Held, Auburn University, had
What a cool observation. It is
possible that the nectar of certain trees may have a narcotic or toxic
effect on bees, although the two references
that I have don’t include goldenrain tree but Sophora spp. In many instances, the toxic effect can be traced
to yeasts associated with the nectar. I would guess that an intoxicated
bee that wasn’t poisoned outright would
die secondarily from desiccation on a hot summer day.
Here are the bee references for
your interest. P.G. Kevan, D. Eisikowitch, S.
Fowle, and K. Thomas. 1988. J. Apic. Res. 27(1): 26-29. P.G. Clinch, T. Palmer-Jones, and
I.W. Forster. 1972. N.Z. J Agric Res. 15:194-201. -alkaloids in the nectar inducing a narcotic effect on bees.
Sam Droege sdroege@...
w 301-497-5840 h 301-390-7759 fax
USGS Patuxent Wildlife Research Center
BARC-EAST, BLDG 308, RM 124 10300
Balt. Ave., Beltsville, MD 20705
As imperceptibly as grief
The summer lapsed away, -
Too imperceptible, at last,
To seem like perfidy.
A quietness distilled,
As twilight long begun,
Or Nature, spending with herself
The dusk drew earlier in,
The morning foreign shone, -
A courteous, yet harrowing grace,
As guest who would be gone.
And thus, without a wing,
Or service of a keel,
Our summer made her light escape
Into the beautiful.
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