Speaking at Glee, where pressure on chemical controls was a big theme, Hagedorn said: "We'll adapt but it's short-sighted. Not giving gardeners the tools is unfair. We have replacements but they're not as effective and more expensive. If it's unsafe I get it, but it's still allowed to be used on food."
Effects of Sublethal Doses of Glyphosate on Honeybee Navigation, recently published in the Journal of Experimental Biology, found that "in honeybees, exposure to levels of glyphosate commonly found in agricultural settings impairs the cognitive capacities needed to retrieve and integrate spatial information for a successful return to the hive. Therefore, honeybee navigation is affected by ingesting traces of the most widely used herbicide worldwide, with potential long-term negative consequences for colony foraging."
Roundup is exclusively marketed by Scotts in North America and most of Europe. Roundup business director Gary Philpotts said: "Glyphosate and glyphosate-based formulations have been extensively tested in the laboratory and in the field. When glyphosate was sprayed on large areas of vegetation adjacent to beehives it was found to have no acute or chronic effects on adult honeybees or brood production, even at concentrations three times higher than usual application rates.
"The conclusions from all of these acute and chronic studies demonstrate that honeybee adults and larvae are not affected by glyphosate or glyphosate-based formulations in realistic field scenarios. These results have also been confirmed by a bee brood study conducted recently to meet the current EU testing requirements for the glyphosate authorisation renewal."
Scotts has dropped metaldehyde from slug killer as the chemical comes under re-registration, using rape seed oil instead. Naturals are eight per cent of Scotts' range, which the company does not see rising "short term".
Bayer has dropped the neonicotinoid thiacloprid, to be replaced by deltamethrin in Provado Ultimate Bug Killer, ahead of regulations changing. Product manager Alison Mulvaney said campaigns against actives including glyphosate were "driven by NGOs and social media pressure. The industry needs to get its defence prepared to protect the actives otherwise we're going to end up with nothing to use in the garden."
Neudorff sales director Jude Beharall said: "European pressure on glyphosate will impact but not to the degree of neonicotinoids. Neonicotinoids are only a slice but glyphosate is almost the whole cake. Traditional gardeners have been using it for decades and unless they're told they can't it will continue to prove popular. It's a cash cow for big garden centres. While it's on the market, it's safe. I have to go with the expert view."
Vitax sales manager Colin Wetherley Mein said: "Pressure on actives is giving us a hard run for our money. We're trying to reinvent the wheel and bringing out alternatives, not that they're as effective. We do the best we can with what we've got."