Sclerotinia Monitoring
Sclerotinia is a common disease of oilseed rape and with closer rotations the disease risk is now increasing. There are some very severe attacks each year, where more than 20% of plants are affected. Yield of affected plants is halved, because of premature ripening. There are well-recognised hotspots of Sclerotinia in the South East and West Midlands in England and Scotland, but severe attacks can occur in most regions of the UK.
A well-timed fungicide spray is usually able to achieve at least 80% reduction in stem rot. Fungicides should be used as protectant treatments, before petal sticking has occurred. The optimum timing is often at early to mid-flowering.
ADAS and BASF have run a service for the past four years, which has proved a popular management tool, to help advisors and growers, assess the disease risk and optimise treatment timing.
Advisors and growers are invited to log on to track Sclerotia germination in their region, to assess disease risk. There will be a bulletin issued every week, for twelve weeks.
The map shows the locations of 6 sites where we are collecting data to monitor the extent of sclerotina:
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Sclerotinia 050609 (13.43 KB)
Published Date: Monday 8th June 2009
Overview: Most crops have finished flowering and seeds are turning green. A considerable number of crops are still at the late flowering stage. Pigeon and pest damaged crops are still likely to keep flowering for several weeks.
Sclerotinia stem rot symptoms are present in some crops in the Hereford area and in the south-west. High risk sites have 5-10% plants affected in untreated areas with lesions developing mainly below the mid-plant level. Fungicides have given good control. In the east and south only traces of infection have been reported so far. The return to unsettled weather could still produce some late infection, though this is unlikely to have much effect on yield.
Sclerotial germination has been lower than usual this season in the depots. However petal tests have confirmed that there has been considerable air-borne production in some fields even where germination was low in the depots. Germination is continuing at low levels and there has been some new activity after recent rain.
Spring oilseed rape is also susceptible to sclerotinia and fungicide treatment should be considered at early to mid-flowering whilst the weather remains unsettled. Crops are at early flowering or close to flowering at present. Cultivation to establish spring oilseed rape could well result in a later germination of sclerotia than that reported for winter oilseed rape. Risks will be higher where soils are moist to the surface.
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Sclerotinia Monitoring - 28th May 2009 (54.65 KB)
Published Date: Thursday 28th May 2009
Most crops have finished flowering and are overall green with full sized translucent seeds. Late crops are still flowering whilst pigeon and pest damaged crops are still likely to keep flowering for several weeks.
Sclerotinia stem rot symptoms are now present in some crops in the Hereford area and in the south-west. High risk sites have 5-10% plants affected with lesions developing mainly below the mid-plant level. Fungicides appear to have given good control. In the east, only traces of infection have been reported so far. The recent unsettled weather has resulted in more petal sticking and more infection could still develop.
Sclerotial germination has been lower than usual this season in the depots. However petal tests have confirmed that there has been considerable air-borne production in some fields even where germination was low in the depots. Germination is continuing at low levels and there has been some new activity after recent rain.. Minimum temperatures are now consistently above 7ºC, the threshold for infection. Crops at high risk sites may still benefit from second fungicide sprays where flowering will continue into June.
Spring oilseed rape is also susceptible to sclerotinia and fungicide treatment should be considered at early to mid-flowering whilst the weather remains unsettled. Cultivation to establish spring oilseed rape could well result in a later germination of sclerotia than that reported for winter oilseed rape. Risks will be higher where soils are moist to the surface.
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Sclerotinia Monitoring - 21 May 2009 (53.35 KB)
Published Date: Thursday 21st May 2009
Many crops have finished flowering and are overall green with full sized translucent seeds. Late crops are still flowering strongly whilst pigeon and pest damaged crops are likely to keep flowering for several weeks. Crops at high risk sites may still benefit from second sprays where flowering will continue up to the end of May. Sclerotial germination is now underway at all 6 depot sites and there has been some new germination after recent heavy rain. Minimum temperatures are now becoming more consistently above 7ºC, the threshold for infection. Some petal sticking has been reported during the last week but this is mainly very light.. Conditions appear to have been most favourable for sclerotinia infection in the west so far this season. Petal tests are showing high levels of sclerotinia at high risk sites (40-50% petals infected). Some early infection could be underway and first symptoms should be evident now.
Spring oilseed rape is also susceptible to sclerotinia and fungicide treatment should be considered at early flowering whilst the weather remains unsettled.
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Sclerotinia Monitoring - 14 May 2009 (53.04 KB)
Published Date: Thursday 14th May 2009
Many crops are rapidly coming to the end of flowering and are overall green with translucent seeds. Later crops are at full flowering whilst pigeon and pest damaged crops are at early flowering. The early end to flowering offers some savings in second fungicide sprays. Sclerotial germination is now underway at all 6 depot sites but the numbers of fruiting bodies (apothecia) has decreased in the recent dry conditions. The first germination has started in North Yorkshire this week. Minimum temperatures are still not consistently above 7ºC, the threshold for infection. Some petal sticking has been reported during the last week in the west and east. Conditions appear to have been most favourable for sclerotinia infection in the west so far this season. Petal tests are showing high levels of sclerotinia at high risk sites (40-50% petals infected). Some early infection could be underway and first symptoms should be evident by mid-May. It is now important to ensure flowering crops remain protected as the weather is unsettled. Where first fungicides were applied 2-3 weeks ago the second spray could be applied soon so that it gives good protection to crops likely to be flowering for the rest of May.
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Sclerotinia Monitoring - 7 May 2009 (52.29 KB)
Published Date: Thursday 7th May 2009
Crops are mainly at full flowering, but forward crops will soon be finished flowering. There is considerable variation within and between crops due to late sowing, variable establishment, pigeon and rabbit damage and lack of rain. Sclerotial germination is now underway at 5 of the 6 depot sites but progressing slowly where sites are dry. Minimum temperatures are still not regularly above 7ºC, the threshold for infection. Conditions have been favourable for sclerotinia infection in the west and in other areas where there has been rain recently. Petal tests are showing high levels of sclerotinia at high risk sites (40-50% petals infected) and only small changes between successive tests. Some infection could be underway and first symptoms should be evident by mid-May. It is now important to ensure flowering crops remain protected. Where first fungicides were applied 2-3 weeks ago the second spray could be applied soon so that it gives good protection for the rest of May.
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Sclerotinia Monitoring - 30 April 2009 (52.26 KB)
Published Date: Thursday 30th April 2009
Crops are mainly at full flowering with few buds remaining on the main raceme. Pods are developing well though some gaps and dead flower buds have been reported. The branches are flowering strongly. Forward crops are at the mid to late flowering stage. There is considerable variation within crops due to variable establishment, pigeon and rabbit damage and lack of rain.
Sclerotial germination is now underway at 5 of the 6 depot sites but progressing slowly where sites are dry. Minimum temperatures are struggling to get above 7ºC on some days so conditions have not been particularly favourable for sclerotinia infection recently. Petal tests are showing high levels of sclerotinia at high risk sites (40-50% petals infected). There has been rain in some areas this week and petal stick has occurred in some crops in the south and west. Some infection could be underway and symptoms should be evident in 2-3 weeks time It is now important to ensure flowering crops remain protected. Where first fungicides were applied 2-3 weeks ago the second spray could be applied later next week so that it gives good protection for the rest of May.
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Sclerotinia Monitoring - 23 April 2009 (51.88 KB)
Published Date: Thursday 23rd April 2009
Crops are mainly between early and mid-flowering with pods starting to develop in the more forward crops. There is considerable variation within crops as some plants are at mid-flowering whilst others are just starting to flower. Pigeon and rabbit damaged areas are still green. Late crops, particularly in the north, are still short and barely at the yellow bud stage. Where there are distinct yellow and green areas within fields, consider using different fungicide timings. Plant height is variable, mostly in the range 70-120 cm tall. Mean soil temperatures are starting to exceed 10ºC in southern and central regions and sclerotial germination is now underway at 5 of the 6 depot sites. Minimum temperatures are above 7ºC on some days so conditions are more favourable for sclerotinia infection than at the same stage last year. Rain is forecast in some areas in the next few days and this could give some sclerotinia infection where petal fall is underway. It is now important to ensure flowering crops are protected before the next rain. Where pgr treatments have been made, the sclerotinia fungicide should be applied 2-3 weeks later.
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Sclerotinia Monitoring - 16 April 2009 (49.13 KB)
Published Date: Thursday 16th April 2009
Crops are mainly in the early stages of flowering but there is considerable variation within and between fields. Late crops are still at the flower buds raised above the leaves stage. Where there are distinct yellow and green areas within fields, consider using different fungicide timings. Plant height is variable, mostly in the range 50-100 cm tall. Mean soil temperatures are starting to exceed 10ºC in southern and central regions and sclerotial germination is now underway at 3 of the depot sites. Minimum temperatures are above 7ºC on some days so conditions are more favourable for sclerotinia infection than at the same stage last year. Rain is forecast in some areas in the next few days and is likely to increase sclerotinia risk. It is now important to start making fungicide applications as crops reach early flowering. Where pgr treatments have been made, the sclerotinia fungicide should be applied 2-3 weeks later.
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