Dr Roy Kennedy told delegates at the Brassica Growers Conference (19 January) that, thanks to research carried out at the university, there is now the potential to detect clubroot at lower spore concentrations than what is picked up by the lateral flow device (LFD).
The spores are detected using an electronic reader, which is able to calculate the level of infestation, unlike the LFD.
On the LFD — nicknamed the "pregnancy test" — a line appears when the disease is present but the extent of the problem is still unknown.
Kennedy added that researchers at Warwick have also successfully achieved magnetic separation — that is, separating clubroot spores from soils. This, he said, means that the clubroot is effectively "fished" out of the soil. "It is hoped that the addition of these [two] steps to the LFD protocol will enable reliable "in field" detection of clubroot resting spores in all soil types. It's going to be a great step forward."
If they are still viable, resting spores can induce the disease in the vegetables years after it first appeared in the crop. New methods for checking if these resting spores are viable have therefore also been developed, said Kennedy. Researchers are staining them to check for the presence of a nucleus, he explained.
"If positive, [this] would indicate potentially viable spores. Spores that do not contain a nucleus can be considered as non-viable as they would not be able to produce a zoospore, which is the spore type that infects roots."
Brassica Growers Association vice-chairman Alistair Ewan told Grower after the conference that the LFD, which has been developed by scientists over recent years, is set to be trialled on a semi-commercial basis this year. He said: "We are hoping the device will go commercial in 2011." The new electronic device is also being trialled this year.
Kennedy also revealed at the conference that trials conducted last year on commercial crops of calabrese near Crail, Scotland, showed that British Sugar's Limex appears to be an effective control method for clubroot.
Each of the four different rates of Limex — which is sugar beet lime and a byproduct of sugar production — applied over the entire trial were successful in reducing clubroot on plants.
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