Developments put in place by Science and Advice for Scottish Agriculture (SASA) to meet the soil testing demands of the new potato cyst nematode directive have resulted in a much faster service for growers, said John Kerr, head of seed protection for SASA.

To tackle the likely large increase in soil being tested as a result of increased sampling rates in the new directive, SASA had invested in new PCR diagnostics and a much more automated system.

That had improved turnaround times from on average 125 days in 2010 to 79 days in 2011, Dr Kerr said. “We’d tested 10,000ha of soil by 20 December compared with 1 February the year before, and 97% of early applications were reported by 31 December, which is a big step forward.”

The increased sampling rate had resulted in an increase of 1.9% in the percentage of land being prohibited from being used for potato seed production to 5.3%.

But because the new system removed any ambiguity over whether land was clean, a greater proportion of land was now unconditionally cleared for planting seed potatoes at 94% compared with 88.7% a year ago, he pointed out. In the previous season, 8% of land tested had been given only a restricted clearance for planting of seed crops.

The new regime should improve the control of PCN, he said. “That is with the proviso that growers do get land to be planted with farm-saved seed tested, and that control programmes are used. If they do those things, control of PCN should improve, which is the aim of the directive.”

Potatoes in practice