Monday, November 24, 2008

Aggregating Lady Beetles

This is a simple case of a “good” guy gone “bad!” The Multi-Colored Asian Lady Beetle is an introduced insect species from Asia that is used to control landscape insect pests in the United States. They have now established themselves in many areas of the U.S., where they reduce populations of aphids and scale insects. However, this lady beetle likes to congregate in large numbers around buildings when they overwinter. This causes them to sometimes move indoors into living areas. These beetles exude a yellowish liquid when disturbed (reflux bleeding), which can stain fabric and can cause skin irritation. They can also bite, which causes a welt to form on the skin!
Exclusion practices should be used to prevent these ladybeetles from entering the structure. All cracks and crevices, such as around windows, doors, air conditioners, and utility pipes should be sealed in late summer and fall. If beetles are spotted inside the home, then a vacuum should be used to remove them. Remember to dispose of the vacuum bag outside, so the beetles do not escape and re-invade the structure.

Multicolored Asian Ladybeetle. Photo by Mike Merchant, Professor and Extension Entomologist, Texas A&M University.

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