The greatest damage caused by the multicolored Asian lady beetle is the discomfort they give to homeowners. It is not uncommon for tens of thousands of beetles to congregate in attics, ceilings and wall voids. When the heating is turned on the beetles tend to move around inside these voids and exit into the living areas of the home.
In addition to biting, they exude a foul-smelling, yellow defensive chemical, which will sometimes cause spotting on walls and other surfaces. Most people are only annoyed by the odor of these chemicals. However, some individuals experience an allergic reaction to the defensive excretions. Sinus irritations and mild skin irritations have been reported subsequent to encounters with the Asian beetle. It is probably not an over-reaction to wash hands or other skin after contacting the beetles. In at least one study, the severity of sinus problems subsided with the removal of beetles from the home.
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Vacuuming may also help to collect beetles in your home. The major complaint for this method is that the beetles become agitated and expel the yellow, foul-smelling repellent, which is then circulated into the air by the vacuum exhaust. Also, it is advisable to empty the bag and beetles after each vacuuming to prevent them from escaping back into the house. It is possible to capture the beetles inside a knee-high nylon stocking that has been inserted into the extension hose or wand and secured in place with a rubber band. As soon as the vacuum cleaner is turned off, be sure to remove the stocking so that the captured beetles cannot escape. As you remove it, the rubber band closes around the stocking, effectively "bagging" the lady beetles. You then can discard the contents of the stocking. This way you will not need to change the bag every time you vacuum every time.