The chemicals have come under pressure from Friends of the Earth after a Professor Dave Goulson study found them on garden centre plants. B&Q have banned their use by its growers after concerns about their links to bee health.
Harnett said: "Recent press based on some scientific data regarding unknown levels of unknown categories of neonicotinoid has created media pressure causing some retailers to formulate a pledge to go neonicotinoid free.
"We can understand this approach from the retailer to ignore the science above and make the statement simply because it is easier than trying to educate the media and public of the differences in the broad category of neonicotinoids, let alone the safe use methods of restricted use neonicotinoids. Also, to understand and inform why neonicotinoids are being used in the combat of key pests, I can empathise will be a task that seems too difficult in the face of media hype in comparison to the potential damage to brand.
"So, what would the consequences of "neonicotinoid-free" be?… Well, with a relatively limited portfolio of effective pesticides at our disposal, if we were to remove all neo-nicotinoids (including those shown to be safe to pollinators) from our crop programmes we would certainly see increased incidents and severity of some key pests through the growing chain, increased issues and shortfalls in crops caused by damage to affected batches and increased costs associated with production due to increased losses and manual tasks to help eradicate pests. With our current knowledge of alternatives available we are convinced that a stance of "neo-nicotinoids free" will not be viable if we are to have any chance to maintain standards. If any body or person can inform us of viable alternatives for these control methods, then we are of course happy to entertain them.
"We wonder whether a more pragmatic stance on accepting use of pollinator friendly neonicotinoids within the supply chain, or to re-classify the cyano-substituted neonicotinoids under a different name, or under a new category of pollinator friendly neonicotinoids, in order to differentiate them from the group of nitro-substituted neonicotinoids implicated in affecting bee behaviour?"