Ladybug is 'biological weapon' in the supermarket

The management of a large supermarket in the US releases about 72,000 ladybirds into stores to kill the aphids.

A ladybug eats aphids on leaves. (Photo: fanpop.com)

Mall of America in Bloomington, Minnesota, USA has an area equivalent to 7 stadiums.30,000 trees are planted - including 400 big trees.They filter the air for the space inside the supermarket, but are also an ideal place for aphids, Livescience reported.

However, aphids have a natural enemy: ladybug. Gardeners appreciate ladybirds in their ability to kill aphids, but they do not harm plants.

'Ladybug is a form of biological defense weapon,' said Lydell Newby, a senior manager of Mall of America.

Mall of America used to release ladybirds into supermarkets to kill other pests.

Some customers complain that ladybirds can fall into food. But a spokesperson for the supermarket said that ladybirds only like to stay on the tree, not to their food.

Experts say ladybirds are the ideal tool to kill aphids in enclosed spaces like houses or supermarkets. However, in an open environment (such as a garden), their ability to kill bed bugs decreases because they tend to be scattered.