Testing soils for pests and diseases prior to planting a potato crop was an essential management tool, according to SCRI's Vivian Blok (left).
Using soil diagnostic tests meant growers could pinpoint soil-borne pests and diseases and take appropriate action early, she said.
"Once they have the diagnostic result and know the scale of the problem they can select suitable fields, varietie and chemical controls and weigh up the economic and environmental impact of planting the crop."
Quantitative diagnostic tests were being developed for potato pests including a tool for assessing the risk of black dot developed by the Scottish Agricultural College. "An assessment tool is already available, but the full disease risk assessment is not yet completed."
The tool had already helped growers on SAC's partnership farms reduce disease risk, said the firm's Stuart Wale. "They have been able to modify their agronomy by putting resistant varieties or short season crops in high risk fields, by using Amistar soil treatments, and by prioritising harvest of affected fields."
The test costs roughly £135 for a 4ha field but, if black dot developed on just 29% of the marketable fraction of the crop, this could reduce returns by as much as £2600, he noted.
Scientists were developing diagnostic tools for powdery scab, black scurf, silver scurf and dickeya species, said Dr Blok. "At this stage they are primarily being used to study the epidemiology of these diseases, but if funding is available they could be developed into to a full commercial tests."
Free-living nematodes
Potato cyst nematodes have been the soil-borne pest of note in the past few years, but free living nematodes must not be forgotten, according to SCRI's Roy Neilson.
"With PCN there are just two species to worry about, but with free-living nematodes there are multiple species."
Testing prior to planting the crop was essential, he said. "One sample should be taken per ha and due to the number of species it is important to have an accurate sampling strategy."