The popular BASF/ADAS Sclerotinia Monitoring Service starts next week and the Outlook section, enhanced by another year’s dataset, has been further improved by offering more detailed information to help advisors and farmers see disease risk in their local area.
“The Sclerotinia monitoring information is generated from seven sites this year - Cambridgeshire, Yorkshire, Herefordshire, Lincolnshire, Kent, Devon and new for this year – Scotland. The data gathered from past years and this year is 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, and results are updated every Monday or Tuesday on the website www.totaloilseedcare.co.uk.
“This year the weekly reports will be more precise in their format, so that farmers and advisors can make a quicker understanding and assessment of their local disease risk. Each site is 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 Sclerotinia risk for their individual postcodes by using the Sclerotinia Outlook service on the www.totaloilseedcare.co.uk website and to make decisions on treatments on forward crops with good plant stands. Sclerotinia Outlook has been further developed this year to improve the resolution at postcode level. Outlook is a colour-coded map of the UK, with green indicating low risk and red indicating high risk.
Headlines from the latest Bulletin are also available via the Totaloilseeds App.
Dr. Caroline Young reminds growers that a soil temperature of 8-10°C and soil moisture is needed for sclerotia to germinate. “Rape crops are at highest risk 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. You need to apply fungicide treatments 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 will then result in high yield responses. In 50 trials where Sclerotinia levels were between 10-60% incidence in the untreated, the average yield increase from a Pictor treatment was 0.53 t/ha. Where Sclerotinia was even higher, between 60-100% incidence, the average yield increase from a Pictor treatment was 0.85 t/ha.”
“Crops at risk need protection and most fungicides are mainly protectant, so it is important to know when disease is likely to come into the crop. Knowing this information puts you in a better position to time fungicide applications correctly, in advance of infection and before any significant petal fall. BASF advise growers to apply Pictor early to mid-flower, before significant petal fall. Filan will also give outstanding results, but it must be mixed with another fungicide with a different mode of action.”
“Pictor is the market leading fungicide in France and Germany where Sclerotinia is a more regular and often more severe disease. It is a very strong candidate as it contains two actives that both control Sclerotinia, and so has in-built resistance management. A different mode of action to the triazoles is a good way to go, especially as Pictor with its two actives will have some activity on Light leaf spot at flowering. The FRAG UK guidelines say that growers should use an alternative active for Light Leaf Spot. Finally, Pictor (and Filan) is 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 and in 48 BASF trials 0.28 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 the year. Obviously yield responses will be much higher as a direct response to high disease control.”
