It’s becoming as common as falling leaves in the fall and flowers in the spring. What I am referring to is homes invaded by lady beetles. In recent years, I have had countless phone calls from homeowners with thousands of lady beetles on the outside walls and in many cases inside the house.
Despite the obvious benefits of lady beetles, they can also be pests. As winter approaches, large groups of adult lady beetles can be found on outside windows, doors, walls and porch decks looking for a suitable overwintering site.
They are particularly attracted to light-colored structures with sunny southwest exposures. On occasion, the beetles attempt to overwinter indoors. As temperatures warm in the spring, the overwintering beetles become active again, leave their overwintering sites and disperse to find food. During these periods of aggregation and dispersal, people often complain that the beetles become a serious nuisance pest.
Prevent entry of lady beetles into houses, storage buildings, attics and other structures by sealing up cracks and crevices in these structures. Use a good quality silicone or silicone-latex caulk to seal cracks and crevices around windows, doors, siding, utility pipes and other openings. Replace or repair damaged door and window screens. Install insect screening (20 mesh maximum) over attic and exhaust vents to prevent entry.
Remove lady beetles inside the home with a broom and dustpan or the vacuum cleaner with the crevice tool attachment. I have been told for the past few years that a trap for lady beetles is being developed, however, I do not know how well the trap works.
Avoid killing beetles found indoors by spraying them with an insecticide or squashing them. Beetles secrete an orange substance from the joints in their legs that, though harmless, can stain walls and fabrics.
In highly sensitive areas such as hospitals, health care facilities, food processing plants and electronic production facilities, invasions of lady beetles cannot be tolerated.
Prevent entry into these areas through screening and caulking cracks and crevices. When beetles cannot be successfully excluded through screening and caulking, insecticides can be applied outside to provide temporary control.
Always follow the label whenever using any pesticides.
Remember that lady beetles do not feed on wood, clothing or human food. Lady beetles: friend or foe? Remember, a weed is simply a plant growing out of place. The benefits of the lady beetles are great, but not in your living room.
Clark Beusse is the Dawson County extension agent. For more information, call (706) 265-2442.