WHEN it comes to protecting bees, gardeners may unwittingly be doing more harm than good.

While many of us have been encouraged to plant flowers beneficial to bees, it appears the pesticides we are using to protect the plants in our gradens could potentially be harmful to these important insects.

In its latest product guide, Ethical Consumer magazine said that nine out of the UK's leading garden centres were selling Provado Ultimate Bug Killer which contains a neonicotinoid chemical known as thiacloprid.

Environmental campaigners say that while thiacloprid is less toxic to bees than three other neonicotinoid pesticides, which have been banned for use on crops attractive to honey bees, there is growing evidence the chemical harms the pollinating insects.

We should all be aware of the importance of protecting bees. They are integral to our food chain - one third of the food we eat would not be available if it wasn't for bees. They bring medicinal benefits too and their harvest is used in medicinal applications, craft and manufacturing.

According to the British Beekeepers Association, 70 crops in the UK are dependent on, or benefit from, visits from bees. They pollinate flowers or many plants which become part of the feed of farm animals.

They have an economic value, too, generating approximately £200m per year as pollinators of commercially-grown crops in the UK so it is imperative we protect them and the more information we have about products that can be potentially harmful to bees, the greater our chance of keeping them safe.

Jane Turner, co-researcher on the Ethical Consumer product guide to garden centres, says: "Gardeners will all be shocked to discover that by using these insecticides they are unwittingly introducing dodgy chemicals into their gardens which are being increasingly implicated in the crisis facing our honey bees.

"We call on garden centres to ensure that they don't sell any products that could harm our bees."

Bill Cadmore, training officer for the Bradford Beekeepers Association, says: "We had thought that the problem was out in the farmland where commercial seed had been treated with neonicotinoid, but it was discovered that a lot of seeds we buy in garden centres also contain it.

"These people who thought they were doing the right thing buying plants and seeds suddenly discovered there was a problem and they did contain the chemical that are suspected of doing harm to bees."

Friends of the Earth's head of campaigns, Andrew Pendleton, says: "With almost one in 10 European wild bees facing extinction and many more under severe threat, we cannot afford to spray chemicals linked to their decline in our gardens and parks. The European Commission must take action on any insecticides with evidence of harm to bees by removing them from sale universally and for good."

A spokesperson for B&Q says: “As a responsible retailer we have been concerned for many years about declining bee health. Our Greener Gardens initiatives help customers to support, engage with and enjoy wildlife in their gardens and in 2014 we worked with Friends of the Earth to launch the first Great British Bee Count app.

"As part of our commitment to protecting wildlife, we reviewed the use of neonicotinoids in our pest control products in 2013. As a result of findings, and in line with EU restrictions, we withdrew all pest control products containing the three substances linked to bee population decline: clothianidin, imidacloprid and thiamethoxam. "At the time, findings for the impact of thiacloprid on bee colony health were inconclusive. Following this new report, we will review our position on thiacloprid and consider the new evidence presented.”

A Homebase spokesman says: "Homebase is a socially responsible retailer and all pesticides we sell fully

comply with EU legislation. We continue to be guided by DEFRA, taking any responsible action with regard

to ranges as directed. We have also recently signed up to support its NationalPollinator Strategy."

Dr Julian Little, a spokesman for Bayer CropScience, makers of the product, says: "The reality is that the active ingredient of Provado, thiacloprid, is extremely safe to bees when used according to the label instructions and users of it can be assured that they can control the destructive pests that would otherwise spoil their gardens in a way that will have no effect on bees."

But it isn't just pesticides that pose a potential threat to bees. Mother Nature is playing a part in their decline too.

According to Bill, due to the mild winter there has been an increase in the level of colony deaths.

"In the cold winters they cluster together and have plenty of stores to keep them alive," explains Bill.

Disease organisms stop re-producing too but in mild winters the bees are at risk of an even greater threat - the varroa mite, an external parasite which can devastate honey bee colonies.