Fending
Off Asian
Lady Beetles
The multicolored
Asian lady beetle is a nuisance (or worse) when they move into people's
homes or businesses in the fall and winter. The beetles often congregate on the
sunnier or warmer sides of buildings in the afternoon or prominent, exposed,
light-colored buildings, looking for suitable overwintering sites (in the walls
or interior of the building itself). While they use visual cues to find a place
initially, once at the chosen site, they then resort to chemical cues to locate the exact crevice they want to inhabit within the
structure. The source of these chemical cues may be
beetle feces from the previous winter, the odor of beetles that died at the
site, or an attractant pheromone.
USDA Agricultural Research Service (ARS)
scientists have found that both camphor and menthol are irritants to the beetle’s chemosensory organs. These
organs – like little taste buds – are so sensitive that the vapors from the two compounds
are
enough to repel the lady beetles. Multicolored Asian lady beetles could
potentially be
controlled using a “push-pull” strategy. They could be “pushed” from
their overwintering sites by the camphor repellant and “pulled” into traps –
using chemicals that mimic the natural cues they use to identify sites –
without harming them.
Until a good "push-pull"
strategy is developed, overwhelmed homeowners could try an indoor blacklight
trap to capture flying beetles entering their home. The trap was invented by an ARS scientist in Georgia as a way to help collect
this beneficial insect without harming the beetles. In
previous ARS tests, the trap captured nearly 100% of the beetles. You can
download instructions
and a schematic for building a trap – in pdf format* – from the USDA-ARS
website. (This site also includes a homeowner
fact sheet about the beetles.) ARS is making the instructions on building the trap accessible on the Web
with hopes that companies will build this much-needed trap. No patents, licenses
or other restrictions apply to using this technology. Companies making the trap
are asked, however, to contact ARS to be added to a “trap builders list”
that will be available as a resource for the general public.
– Susan Mahr, University
of Wisconsin - Madison (from ARS News releases and other documents)
* Click
here if you need the free Adobe Acrobat Reader for PDF files.
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