The Defra WOSR disease survey has shown that LLS is now the number one disease threat in OSR. In some seasons it has been estimated to have cost UK growers close to £160m, and CropMonitor data reveals that the disease is now widespread, even in southern and eastern counties.
It’s that combination of the threat and being so difficult to identify that led to the initiative. “LLS is particularly difficult to identify, especially in its early stages, and it can be mistaken for fertiliser scorch, frost damage, plant stress or downy mildew,” says Claire Matthewman, Bayer’s OSR fungicide campaign manager.
Julie Smith of ADAS agrees and says that misdiagnosis or not being spotted early enough impairs control. “With LLS you have to remain in a protective position. Our trials have shown the importance of fungicide timing. Control can be reduced to 40-50% if the disease is established.”
AICC CEO Sarah Cowlrick says that it’s important to get a countrywide view of LLS incidence. “This has been a disease that has rapidly spread south, many members are now reporting LLS within their area. We’re delighted to be involved to help build this comprehensive picture of LLS incidence and severity, and our network of crop consultants allows us to do this.”
AICC chairman Sean Sparling agrees and points out that the initiative will aid our knowledge of the disease.
What diseases will SpotCheck help identify?
Samples will be examined for a range of diseases including Phoma, Alternaria and downy mildew, but the focus is on LLS which Julie describes as OSR’s Septoria. It can be several weeks from infection before symptoms become visible.
What do growers and agronomists have to do to use the SpotCheck service?
To use the service all a grower or agronomist needs to do is to telephone ADAS Rosemaund - 01432 820444 - to request a sample kit. The sample kit contains:
AICC members can request a sample kit from AICC HQ.
Results can be expected within five working days.
The objective of SpotCheck is to confirm the presence (or absence) of disease in commercial crops. Therefore, samples can be sent before or after a fungicide application, as long as we know if/when fungicide was applied.
If plants/leaves are sampled within about two weeks following fungicide application it is unlikely that we will see disease symptoms (except for old symptoms which were already present) so the value to the grower/agronomist is likely to be diminished.