Introduction of Asian ladybugs into Europe was a serious mistake

Wageningen University: In retrospect, introducing the Asian ladybug into Europe was a serious mistake. The insect was introduced some twenty years ago in a conscious attempt to combat aphids. But research carried out at Wageningen UR (University & Research centre) into the invasion of this foreign insect has shown that the disadvantages far outweigh this single advantage. The Asian species is displacing the native European ladybug and has become a pest that can contaminate homes and spoil the taste of wine. The researchers concerned have reported their findings in the latest edition of the scientific journal Plos One.

The Asian ladybug, Harmonia axyridis, which originated in China and Japan, is larger than its European counterpart and has an almost invisible dent towards the rear of its wing cover; the colour and dots are much the same.

The foreign insect was introduced into France in the early 90s, and was first used in the Netherlands in around 1996. The Asian ladybug was a formidable weapon in the fight against aphids in greenhouses and on avenue trees, from which lice excrete sticky honeydew onto cars.

However, time has shown that these insects, which have very few natural enemies in Europe, are also devouring the native ladybugs. Furthermore, colonies of the Asian variety hibernate in houses and other buildings, where their excrement can cause contamination. Last but least, it has been discovered that when the supply of aphids runs out, this insect has an appetite for grapes and spoils the taste of the wine.

...On discovering that introducing Asian ladybugs had been a mistake, use of these insects in Europe was banned. Unfortunately, populations had already become well-established in many European countries. The best way to tackle the nuisance caused by non-native animals and plants is to introduce natural enemies. But this too can be a risky business, which is why the Netherlands has asked Wageningen University and the Plant Protection Service [Plantenziektekundige Dienst] to draw up an environmental risk analysis for the natural enemies of non-native species....

Asian ladybug, shot by John Alan Elson, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported