ARKANSAS If large numbers of lady beetles gather around the home, it may be a sign of a multicolored Asian lady beetle infestation, said Dr. John Hopkins, extension urban entomologist with the University of Arkansas Division of Agriculture.
The multicolored Asian lady beetle is an effective predator of aphids, Hopkins said.
“This insect was first introduced into the U.S. in the early 1900s and, after numerous subsequent releases, became permanently established across the country,” he said.
Multicolored Asian lady beetle adults differ from other lady beetle species by their distinctive white, oval markings behind the head that form a black Mshaped pattern. Adults are approximately a quarter-inch in length with colors ranging from yellowish orange to bright red. Nineteen black spots feature prominently on most lady beetles’ forewings. Contrary to popular belief, however, they do not indicate the age of the insect.
For all their delicate beauty, however, the Asian lady beetles can be quite the pest.
Unlike other native species, the Asian lady beetle prefers to overwinter in and around buildings, Hopkins said. Large, hidden aggregations of the insects may be found in dark, secluded areas of the home such as attics and basements.
These tendencies can bring the insects into close contact with humans.
Asian lady beetles react when disturbed, exuding a foul-smelling, yelloworange liquid that can permanently stain walls, carpeting, drapes and furniture.
“Do not swat or crush this lady beetle to reduce the likelihood of this defensive behavior,” said Hopkins.
The insects also use a more aggressive form of defense: biting.
“These bites may cause welts that last 24 to 48 hours,” said Hopkins. In extreme cases, humans may have an allergic reaction to the bites, resulting in dermatitis and a stinging sensation.
Multicolored Asian lady beetles begin to congregate in late summer or early fall, and swarm on the first warm day after the temperature has dropped to near or below freezing, said Hopkins.
Keeping the multicolored Asian Lady Beetle out of the home is the best defense. Hopkins offered a few recommendations to help keep the lady beetles out:
• Seal/Caulk — Use good quality silicone or silicone latex caulk to seal cracks and small holes throughout the house, especially around windows and doors. Install tight-fitting sweeps and rubber seals on garage doors.
• Screen — Install screens (20-mesh maximum) over all vents and replace or repair damaged door and window screens. Leave screens on windows instead of storing them.
• Pesticides — Have sections of the outside of the house sprayed with an appropriately labeled pyrethroid insecticide no more than two weeks before the beetles usually arrive. Concentrate applications on areas around windows, under eaves, along rooflines and around foundations. Applications are effective for about 3 weeks, less if it rains frequently.
• Camphor — Put camphor cakes or crystallized camphor in a nylon stocking. Knot the stocking and hang it on the outside of the house near known entry points, or put cotton balls containing a few drops of camphor essential oil in the corners of the windows. Reapply the oil often.
Hopkins offered other methods if the lady beetles have already infested the home.
Commercial “black light traps” use ultraviolet light to attract the insects and a talc-lined container to keep them from escaping. Instructions for homemade light traps are available at http://www.ars.usda.gov/is/pr/2000/001 030.htm.
Vacuuming is a more conventionally effective method for removal.
Insert a nylon stocking into the end of the extension hose or wand to bag the insects and secure the stocking in place with a rubber band. The rubber band will close around the stocking as it is removed, effectively capturing the lady beetles. As soon as the vacuum cleaner is turned off, remove the stocking and discard its contents.
For more information about pest control around the house, visit www.uaex.edu or contact your county extension office.
News, Pages 7 on 12/02/2009
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