Sclerotinia has reportedly become more widespread and troublesome in carrots, causing rotting of roots and foliage and decreasing yield and quality. Now, BASF and ADAS are sponsoring a Sclerotinia monitoring system that helps carrot growers assess their disease risk is starting in the first week of June this year. Weekly results are available to growers and advisors on the Carrot Sclerotinia Monitoring link on www.agriCentre.basf.co.uk .
Dr Peter Gladders, plant pathologist for ADAS, pointed out that it is particularly important to get the first fungicide spray on early enough as disease risk increases once the canopy closes over. He advised that they should keep checking the published information on the web and be ready to take action.
Sclerotinia survives in the soil as resting bodies or sclerotia, which germinate when conditions are favourable. The Sclerotinia system monitors the germination pattern of sclerotia taken from carrot crops.
The system involves burying batches of sclerotia in cereals fields last winter and leaving them undisturbed to overwinter. Half of the batch is then dug up in the spring and reburied in a nearby carrot fields, so imitating the disturbance due to cultivation and drilling.
There are three sites: Norfolk, Nottinghamshire and Scotland. Sclerotia germination takes place when the soil is moist and temperatures are between 5C- 25C, with optimum temperatures being 15C-25C. Germination will be monitored weekly throughout June to August.
As the sclerotia provide the source of infection within the carrot crop, this will indicate the timing of Sclerotinia risk and the need for fungicide treatment
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