Cavity spot is a major problem for carrot growers but development of the disease is highly dependent on environmental factors so it cannot be easily predicted before planting.
In the new HDC project FV 405 (Carrots: Control of carrot cavity spot through the use of pre-crop green manures/biofumigation) the Warwick Crop Centre research team, led by John Clarkson, is building on preliminary work by Dez Barbara where chopping and incorporation of hot varieties of mustard along with a plastic film covering were demonstrated to effectively control carrot cavity spot.
In this project, the team will investigate whether the mustards and other green manures can provide effective control in a commercial setting - even without the expensive sealing film - in order to develop a commercially viable pre-carrot "insurance policy" against the risk of cavity spot.
The project will also investigate whether hot mustards have any beneficial effects on numbers of free-living parasitic nematodes and/or on Sclerotinia sclerotiorum sclerotia. It is hoped that a sustainable disease-control method can be developed that is acceptable for both conventional and organic production systems.
A summary of the project can be found on the HDC website at www.hdc.org.uk.
A wallchart of nutrient deficiencies of brassicas has been distributed to brassica growers. Levy payers can order further copies from the HDC office on 0247 669 2051.
Horticultural Development Company
For details on all HDC activity, visit www.hdc.org.uk