Vegetable Club Root Soil Test

Club Root Disease (Plasmodiphora brassicae) is a serious pathogen which infects the roots of vegetables such as cabbage, cauliflower and broccoli. Infected roots develop swollen galls, which reduces their capacity to absorb water from the soil and consequently affected plants wilt in dry weather. Vegetable growers employ tactics such as crop rotations and lime applications to combat this persistent and damaging fungus. Rotation planning gives the fields a break from brassicas to prevent a build-up of club root in the soil, and liming products raise the pH of the soil to deter club root development. But the pathogen survives successfully on weeds and can adapt to living with lime, so the disease still gives nasty surprises.

From a growers’ point of view, knowledge is power, so growers who know the club root level in their fields can anticipate the disease before damaging effects occur on the crop. CAFRE is holding a training course to demonstrate how testing of soil can be carried out to determine the level of club root

The standard soil testing method for club root has mainly been used by researchers, but does not need any special laboratory equipment. The soil test sample is used to grow seeds of a susceptible variety of Chinese cabbage. After six weeks, if club root is present, the characteristic galls will be clearly visible on these test plants.

On 24 August 2010, growers can bring soil samples to the ‘Sparky Pak’ site near Comber to start the process to determine the level of club root in fields which they are considering growing vegetables in next year. The second session, on 5 October, will provide the ‘moment of truth’ when growers wash the roots to reveal any galls thereby determining the level of club root in the soil sample.

Running the tests is valuable but does take some time and care. Hard-pressed growers can delegate the preparation and running of the tests to other farm family members, who will be very welcome at the training sessions.

With their new ability to test soils for club root, brassica growers will be better informed to make management decisions on choice of crop and treatments required.  

For additional information or to reserve a training place please contact Dr Anne Stone at Greenmount Campus, CAFRE on 02894 426683, or 07500 957895 or anne.stone@dardni.gov.uk

Healthy roots of Chinese cabbage

Galls on Chinese cabbage, revealing club root