To: ANR Agents
From: Eric Day
Re: Insect Update
Now is the time for Lady Beetles to start moving into houses.
The most common one in houses is Harmonia axyridis, the Multicolored Asian Lady Beetle, also called the "Japanese Lady Beetle".
Hosts: Feeds on tree dwelling aphids in the summer, invades houses in huge numbers each fall looking for an overwintering site. This lady beetle does not carry disease but will bite in rare cases. When crushed it will leave a brown stain.
Natural Overwintering Sites: Fence rows, rock piles, hollow trees, and cliff faces are this lady beetle's prefered overwintering sites. Getting into houses is a fatal mistake because a house has low humidity and these and most other insects simply dry out and die. It may take several weeks for them to die so they still create a nuisence as they fly about and collect on the ceiling.
Control: The best control is to keep them out. Conduct an energy audit of the house and seal up all possible openings for heat loss as these beetles will enter the house through cracks in windows and walls and under doors. If they get in to the house sweep them up with a vacuum cleaner and discard the bag often. If you spray, use an aersol insecticide labeled for household insects but be sure to vacuum up the dead beetles.
Remarks: These beeltes are now found in most of the United States and get in to houses throughout their range. In one case in Oregon the lady beetles built up to a depth of ONE FOOT in the attic of a house.
Prepared by Eric R. Day, Virginia Polytechnic Institute and State University
Eric Day
Insect Identification Laboratory
Department of Entomology
307 Price Hall
Virginia Polytechnic Institute and State University
Blacksburg, VA 24061
(W) 540-231-4899
Fax 540-231-9131
idlab@vt.edu
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