Sclerotinia in carrots appears to be getting worse year on year and growers are advised to start their fungicide programmes earlier with a strong fungicide treatment.

That’s according to Howard Hinds of Howard Hinds Crop Consultancy. “In the last ten years that I have been involved with carrot crop consulting, I have noticed that Sclerotinia has become a much more widespread and serious disease in this crop. Consequently carrot growers are getting a lot tighter with their fungicide programmes and are starting their programmes earlier. They are also using more robust programmes right from the start,” he says. “Once Sclerotinia has become established, it is very difficult to keep on top of, so ideally I would advocate the use of a strong and robust first spray.”

He recommends Signum. “The plant health effects of Signum are particularly significant in fruit and vegetable crops where quality, visual impact, yield and storage characteristics are all important. The inhibition of ethylene will mean that crops are less stressed and so yields are improved. Such crops also tend to have a greater tolerance of drought or water logging. Signum also helps the plant maximise nitrogen uptake and utilisation, through effects on nitrate reductase production. This means more efficient use of nitrogen and correspondingly higher yields”.

He points out that it is also important to apply the first Signum spray at the correct timing. “With infection taking place on older stems and leaves below the canopy, it is important to make the first application of Signum before the crop canopy closes over or before an infection period has occurred according to Decision Support Systems. This allows the product to get right down into the crop. Usually the first application is made around early July when the crop coverage is 50 to 70% of the ground. Water volumes need to be sufficient to give good spray penetration,” says Hinds.

A second spray of Signum should be applied after a fungicide with an alternative mode of action, e.g. tebuconazole has been used.