Camphor Curbs Asian Lady Beetles
January 30, 2001
Camphor effectively repels the multicolored Asian lady beetle
and could be a way to repel the insects as they attempt to overwinter indoors,
Agricultural Research Service scientists
report in a recently published paper.
The results may help researchers balance the need for protecting
this beneficial insect against the publics concern for the nuisance the
beetles create when they congregate in peoples homes and businesses. The
research was published in the November 2000 issue of the
Annals of the Entomological Society of
The multicolored Asian lady beetle, Harmonia axyridis,
originally from China, was introduced to the United States in 1916. The beetle
has been an effective biological control agent for aphids and scale
Researchers with the
Insect Behavior Laboratory in Beltsville, Md., used bioassays to determine
the ability of the plant compounds camphor and menthol to repel the beetle.
Preliminary test results indicate that camphor and menthol vapors are an
irritant to the beetles chemosensory organs. These organs--like little
taste buds--were found to be so sensitive that the vapors from the two
compounds were enough to repel the lady beetles.
Other scientists have found that adult beetles use visual or
physical cues to find acceptable overwintering sites. These locations are
usually the sunnier or warmer sides of buildings in the afternoon or prominent,
exposed, light-colored buildings. Once beetles are at the chosen site, they
then resort to using chemical cues to locate the exact crevice they want to
inhabit within the structure. Researchers believe that 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.
This evidence suggests that multicolored Asian lady beetles
could 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.
ARS is the chief scientific research agency in the
U.S. Department of Agriculture.
Scientific contact: Eric W Riddick, ARS
Biological Control and
Mass Rearing Research Unit, Mississippi State, Miss., phone (662) 320-7382,
fax (662) 320-7571, firstname.lastname@example.org