Number one problem for UK crops highlighted

It has been reported that root knot nematode (Meloidogyne minor) may become the number one problem in the UK over the next decade in a broad range of crops, with numbers having increased by 300% in the last 30 years.

At a technical briefing held by Certis, Dr Colin Fleming, principal scientific officer at the Agri-Food and Biosciences Institute in Belfast, explained that several factors are probably significant in the increase of the nematode populations.

“The climate is changing and we are seeing warmer, wetter weather patterns that favour nematodes and are encouraging species that prefer warmth, like the root knot, to thrive,” he said. “The reduction in the number of active substances available for use in agriculture is also having an effect.”

Robert Lidstone, Certis’ marketing and business development manager, explained that the addition of NEMguard – a proven nematicide – to their portfolio couldn’t have come at a more pertinent time.

“Growers of carrots and parsnips are turning to NEMguard as a viable alternative to carbamate chemistry. The active substance in NEMguard is garlic extract, a naturally derived product which benefits from no MRL (maximum residue limit) or harvest interval.


The mode of action of NEMguard is well researched and its efficacy backed by science, added Mr Lidstone.

So how does garlic work to control nematode populations? Dr Chris Hamilton, who has been working with sulfur chemistry at the University of East Anglia for a number of years, explained some basic biochemistry, and the background research behind NEMguard.

“When garlic cells are ruptured and then heated, a breakdown substance is produced which contains diallyl polysulfides, these molecules are able to elicit a cascade of different changes within the metabolism of the nematode that ultimately kills them,” he explained. “These polysulfides have multisite activity so resistance is unlikely.”

In order to gain pesticide approval, the nematicidal activity of NEMguard has already had to be demonstrated to CRD. There are extensive quality controls in place to make sure NEMguard consistently contains the ‘right’ mix of polysulfides to maintain its efficacy and ensure a long-term release, reiterated Mr Lidstone.