Potato growers which incorporate a brassica crop into their rotation could see rotation lengths reduced by four years, according to Prof Peter Urwin of the University of Leeds.
In a study alongside Harper Adams University, Prof Urwin told the audience how a decline in rates of PCN, which typically fall by 33 per cent each year, were reduced by almost 70 per cent where oilseed rape was grown in the rotation.
He said: “This was absolutely eye-watering to us because normally the aim with biofumigants is to grow oilseed rape and mulch it into the soil and the glucosinolates which come off the oilseed rape have a nematocidal effect on the PCN.
“What this tells us is those brassica crops are having a detrimental effect on the PCN long before they have been mulched into the ground.
“This is an enormous decline rate and we estimate having this biofumigation crop could reduce rotation lengths by four years.”
A difference of 5 per cent in PCN decline rates can shorten the rotation by two years, which is why it is important for each grower to monitor populations, said Prof Urwin.
“Decline rates themselves are very important. If you know how many years it is since you grew a potato crop and take a sample of females and break them open to do an egg count you will be able to determine the decline rate. It’s a simple way of working out PCN egg decline rates at individual field level, influencing the duration of rotation course needed to restore a population to previous levels.”