Aphids are small insects that pierce plant leaves and suck out their contents. They can cause considerable crop damage. Although they inflict limited physical destruction to the plant, aphids commonly infect plants with viruses, which can destroy complete harvests .
Did you know that ornamental flowers are amongst the main export products of the Netherlands? Well, now you do. So you can imagine the Dutch not liking tiny pest insects (aphids and thrips) damaging and infesting them with viruses.