Coccinellidae - Infestations and Impacts

Infestations and Impacts

In the United States, coccinellids usually begin to appear indoors in the fall. They leave their summer feeding sites in fields, forests and yards looking for a place to spend the winter. Typically when temperatures warm to the mid-60s Fahrenheit (around 18°C) in the late afternoon, following a period of cooler weather, they will swarm onto or into buildings illuminated by the sun. Swarms of Coccinellids fly to buildings in September through November depending on location and weather conditions. Also, homes or buildings near fields or woods are more prone to infestation.

The presence of Coccinellids in grape harvests can cause ladybird taint in wines produced from the grapes.

After an abnormally long period of hot dry weather in the Summer of 1976 in the UK, there was a marked increase in the aphid population followed by a "plague" of ladybirds, with many reports of people being bitten as the supply of aphids dwindled. Recent studies suggest that coccinellids can also cause allergic reactions, such as eye irritation or asthma.