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Adding another years dataset to make it even more accurate, the popular BASF/ADAS Sclerotinia Monitoring Service starts soon and the Sclerotinia Outlook section offers more detailed information to help advisors and farmers see disease risk in their local area.

“As a reminder the Sclerotinia monitoring information is generated from seven sites - Cambridgeshire, Yorkshire, Herefordshire, Lincolnshire, Kent, Devon and Scotland. The data is gathered from past years and can be used to generate a local risk assessment," ADAS plant pathologist Dr. Caroline Young says.
She explains that germination assessments are made each week for a 12 week period, running into June, with results updated every Friday or Monday on the BASF rape website www.totaloilseedcare.co.uk.  “Last year we made the weekly reports more precise, so that farmers and advisors could quickly understand of their local risk. Each monitoring site is further supported by petal tests at first flower, early flower and mid-flower, which will help establish disease pressure from air-borne spores,” she says.

Caroline advises growers to check their Sclerotinia risk for their individual postcodes by using the Sclerotinia Outlook service on the www.totaloilseedcare.co.uk website and use this information to make decisions on treatments on forward crops with good plant stands. Sclerotinia Outlook will indicate disease risk at postcode level, using a colour-coded map of the UK, with green being low risk and red being high risk. Publication of the latest bulletin is also posted on Twitter; @totaloilseeds.

Dr. Caroline Young reminds growers that a soil temperature of 8-10°C is needed for its over wintering bodies sclerotia to germinate and release airborne spores.  “Right now soil temperatures are relatively cool below 9 to 10 °C so germination has not started in most places. But it has already started in one location in Devon. As soon as soil temperatures warm up, germination and spore release is bound to occur where soils are damp. The crops aren’t in flower yet but some in the south are not far off. So germination could coincide with early flower for many crops this year, which would result in a high infection risk, if there are a couple of warm days and nights at that time. Rape crops are at highest risk from Sclerotinia when sclerotial germination synchronises with early flowering. Spores infect the plant when minimum temperatures are above 7°C and there are long periods of high humidity. Fungicide treatments need to be applied before infection and this is where the Outlook service is most useful. By using the Outlook service, it can help to prioritise spraying demands.”

Sclerotinia is an important disease of oilseed rape, causing yield losses of 30 to 50% in severely affected crops, warns BASF Business Development Manager Clare Tucker. “Effective fungicide treatments such as Pictor (boscalid and dimoxystrobin) will give excellent Sclerotinia control, around 85% in trials, which then will result in high yield responses.”

“Crops at risk need protection and with most fungicides being mainly protectant, it is important to know when disease is likely to come into the crop. Knowing this information puts you in a better place to time fungicide applications effectively, in advance of disease and before any significant petal fall. BASF advise growers to apply Pictor early to mid-flower fungicide before petal fall. Filan (boscalid) will also give outstanding results but it must be mixed with another fungicide with a different mode of action as a resistance management measure.”

“Pictor has been the market leading fungicide in several European countries where Sclerotinia is a more regular and often more severe disease. It is a strong candidate as it contains two actives both of which control Sclerotinia and so has in-built resistance management. A different mode of action to the triazoles is also the best way forward, especially as Pictor also has two actives with some activity on Light leaf spot at flowering. The FWAG guidelines say that growers should be using an alternative to triazoles for Light Leaf spot. Finally Pictor (and Filan) are bee safe and can be mixed with pyrethroids for seed weevil control at flowering. As with all sprays it is important to ensure that bees are not foraging actively in the crop at the time of spraying.”

Clare reports that both Pictor and Filan give excellent control of Sclerotinia and both give a yield increase when there is no disease present. “In independent ADAS trials this was 0.22 t/ha. This yield comes from leaf and pod greening and improved water use efficiency for seed-fill– water uptake can be limiting at this time of year. Obviously yield responses will be additionally higher as a direct response to high disease control as well as physiological effects.”