Stefan Buczacki solves your plot problems
Pauline Hunt, London
Stefan says: You read recently that two years ago the EU banned the use of the pesticide thiamethoxam, but that England has now ‘disregarded the ban’ and authorised its use. You saw that the main argument against the product is that it is believed to kill bees, yet we, as gardeners, have been encouraged to promote the spread of bees after finding there has been a distinct decline in numbers over the past few years. Why the apparent contradiction, you wonder.
You’re right to raise this matter. Thiamethoxam belongs to a group of chemicals called neonicotinoids. These chemicals have what we call a broad spectrum of activity. They will kill a wide range of different types of insect by affecting the insects’ central nervous system. And among the insects are bees. Because of this, in 2018, the EU banned the outdoor use of the three most widely used neonicotinoids: thiamethoxam, clothianidin and imidacloprid. Even so, collectively, neonicotinoids are still widely used elsewhere. They account for one quarter of all global insecticide sales and it has been claimed that without them, many people, especially in less advanced countries, would starve. Thiamethoxam itself is said to be the most widely used insecticide in the world.
Although, by and large, the UK is now expected to follow most of the EU rules and guidance about agro-chemicals after Brexit, the government decided to make a temporary exception in this case. The reason is because of a serious virus disease of sugar beet, which is transmitted by aphids and threatens the British sugar industry. It’s believed that treating sugar beet seed with thiamethoxam for two or three years to control the aphids will help significantly.
It shows that garden chemicals are just part of a wider situation and, in fact, a fourth neonicotinoid, acetamiprid, claimed to be less toxic to bees, is still available for garden use.