Initial observations from a new HGCA club root project suggest applications of fertilisers that rapidly release calcium could help improve performance of both susceptible and resistant oilseed rape varieties, Peter Gladders of ADAS says.

Recent DEFRA-funded research has shown that raising both pH and soil calcium levels helps control club root in vegetables, he explains.

Products, such as the calcium-rich nitrogen fertiliser Perlka and Limex from British Sugar that release calcium more rapidly than traditional calcium fertilisers have shown good control of club root in calabrese.

Clubroot large

Carl Gibbard of KWS UK inspects Mendel plots treated with Limex. A plot of the susceptible variety Komando is in the foreground.

The project is investigating whether the same can be seen in oilseed rape. “We’re hoping that there is a much stronger effect from a product that gives a burst of calcium when the crop is at a susceptible stage.”

So far, initial results at the Shropshire site suggest Limex and Perlka can contribute to club root control, even where the resistant variety Mendel is grown, he says. “Mendel’s resistance makes a substantial contribution, but even that needs some lime treatment on a highly infected site.”

The project is also trying to link club root inoculum levels in soils to what combinations of treatment might be required. “For example, a lower level might only need a resistant variety, while higher disease loading could also require liming.”