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.
 56 28 May 2008 Sclerotinia Monitoring Bulletin (86.32 KB)
Published Date: Wednesday 28th May 2008
Most crops have finished flowering and seeds are translucent or green in the pods. Late crops and pigeon damaged areas are likely to continue flowering for some time as more branches are produced. Note that some of the late flowering is charlock rather than oilseed rape. There have been several days with heavy rain in many areas and this could still lead to some new sclerotinia infection as there are still petals lodged in the leaf axils. Will this repeat the 2007 pattern? Where petals are sticking to the leaves there are leaf lesions caused by sclerotinia and/or botrytis.
More sclerotinia stem lesions have been confirmed in the south, mainly at mid-stem level but a few are at soil level. Sclerotinia stem symptoms at this stage probably indicate late April infection. It is useful to assess disease levels now and again in 4 weeks time to gauge when infection occurred and to appraise control strategies. In south, some alternaria has been found and this could still cause problems if the weather remains unsettled. Final decisions are required for alternaria to protect developing pods.
As soils are wet, sclerotinia germination has increased again at most sites and may well continue after flowering to threaten other arable crops. The highest total germination is at ADAS Rosemaund where there has now been 49% germination, the same as last week. There was 7% new germination at Boxworth, Cambs, 12% at the Kent site on Romney Marsh and 8% at ADAS Terrington, giving rather similar total germination of 29-39% at sites in the east and south. The depot at High Mowthorpe on the Yorkshire Wolds had 1% new germination and has still only had 2% germination in total.
- Sclerotinia monitoring bulletin 55 (86.28 KB)
Published Date: Wednesday 21st May 2008
Most crops are close to the end of flowering and have seeds expanding in the pods. Forward crops have finished flowering. Late crops and pigeon damaged areas are likely to continue flowering for time as more branches are produced. Some petal sticking has been reported and leaf lesions are becoming more evident particularly in the west. Sclerotinia and botrytis are likely to be causing these lesions. The first sclerotinia stem lesions are appearing in the Hereford area, indicating some infection occurred in April (possible infection during 23-24 April and 29-30 April). More rain is forecast for late May Bank Holiday weekend and this may provide the last conditions for petal sticking and infection in later flowering crops. As the sclerotinia risk is still present, a second fungicide treatment may be worthwhile to maintain protection at high risk sites until the end of flowering. In south, where alternaria continues to cause problems in a few crops each year, final decisions are required to protect developing pods.
Sclerotinia germination has increased slightly at all sites in southern, eastern and westem England and soils have remained moist at the surface. The highest germination is at ADAS Rosemaund where there has now been 49% germination, an increase of 3% since last week. There was 4% new germination at Boxworth, Cambs, 11% at the Kent site on Romney Marsh and 8% at ADAS Terrington, giving rather similar total germination of 22-30% at sites in the east and south. The depot at High Mowthorpe on the Yorkshire Wolds had its first germination (1%) last week, but no further germination took place in drying conditions this week.
- 54 14 May 2008 Sclerotinia Monitoring Bulletin (86.17 KB)
Published Date: Wednesday 14th May 2008
Most crops are at the late–flowering stage and most pods are set on the main racemes. Forward crops have finished flowering. Late crops and pigeon damaged areas are likely to continue flowering for time as more branches are produced. Some petal sticking has been reported, but recent hot dry weather has resulted in large numbers of petals settling on the ground. Rain is forecast from 15 May onwards and this may provide the last conditions for petal sticking and infection before the end of flowering. As the sclerotinia risk is still present, a second fungicide treatment may be worthwhile to maintain protection at high risk sites until the end of flowering.
Sclerotinia germination has increased slightly at all sites in southern, eastern and westem England and soils have become dry at the surface. The highest germination is at ADAS Rosemaund where there has now been 46% germination, an increase of 13% since last week. There was 1% new germination at Boxworth, Cambs, 1% at the Kent site on Romney Marsh and 3% at ADAS Terrington, giving rather similar total germination of 16-22% at sites in the east and south. The depot at High Mowthorpe on the Yorkshire Wolds has shown its first germination (1%) this week. The older apothecia have shrivelled this week, but could soon be producing spores again if it rains.
- Sclerotinian monitoring bulletin 7th may 08 (85.61 KB)
Published Date: Wednesday 07th May 2008
Most crops are flowering strongly and moving from mid to late–flowering and setting pods. Forward crops have almost finished flowering on the main raceme. Some late crops and pigeon damaged areas are still green and between the yellow bud and early flowering stages. Some petal sticking has been reported, though generally in low numbers as heavy rain tended to wash petals off the foliage and hence reduce the sclerotinia risk. As the sclerotinia risk is still increasing, a second fungicide treatment may be worthwhile to maintain protection at high risk sites until the end of flowering.
Sclerotinia germination has increased at all sites in southern, eastern and westem England as soils have been moist. The highest germination is at ADAS Rosemaund where there has now been 33% germination, an increase of 9% since last week. There was 11% new germination at Boxworth, Cambs, 6% at the Kent site on Romney Marsh and 10% at ADAS Terrington, giving rather similar total germination of 15-19% at sites in the east and south. Only the depot at High Mowthorpe on the Yorkshire Wolds still has no germination. The new apothecia are still expanding and will be producing spores in increasing numbers. Several dry days are likely to favour dispersal of air-borne sclerotinia spores so the risks of infection are expected to increase if the weather becomes showery and leads to petal sticking during the next week.
- 30-April Sclerotinia Monitoring Bulletin (85.44 KB)
Published Date: Wednesday 30th April 2008
After warm dry weather at the end of last week, most crops are flowering strongly and moving from early to mid-flowering. Some late crops and pigeon damaged areas are still green and between the yellow bud and early flowering stages. Forward crops are beyond the mid-flowering stage with pods developing. Progress was made with sclerotinia fungicide applications last week, but rain is hampering spraying this week. Fortunately some of this rain has been heavy so it may have washed petals off the foliage and reduced the sclerotinia risk. There is some urgency to protect untreated crops that are flowering against sclerotinia.
Sclerotinia germination has increased quite dramatically from 5% to 24% at ADAS Rosemaund this week. There was 4-6% new germination at Boxworth, Cambs, the Kent site on Romney Marsh and at ADAS Terrington. There was more rain in the Rosemaund area last week so soils have been moist at the surface, but germination could now increase quickly in other regions after more widespread rain this week. Only the depot at High Mowthorpe on the Yorkshire Wolds still has no germination. Apothecia have also been found in winter wheat after winter oilseed rape with sclerotinia in 2007 in The Thames valley area. It is now a good time to look for apothecia in winter cereal crops where you know there have been sclerotinia problems in previous years. Sclerotinia spores are likely to be able to spread from infested cereal fields to nearby oilseed rape crops. Finding apothecia nearby would justify fungicide treatment on oilseed rape.
- Sclerotinia bulletin 23-4-08 (85.33 KB)
Published Date: Wednesday 23rd April 2008
There has been limited crop development during the last week and growth stages are still mainly between the yellow bud and early flowering stages. Some forward crops are at the mid-flowering stage with a few small pods. Flowering is more advanced in some varieties such as Excalibur. Severe pigeon damage is now very conspicuous and contributing the large variation within crops. Some sclerotinia fungicides have been applied at early flowering and many crops are likely to require treatment during the next 10 days.
Sclerotinia germination has started this week at ADAS Terrington. Four out of the 5 depots are now showing germination, which leaves only the traditionallly late site at High Mowthorpe on the Yorkshire Wolds with no activity in the depot. At Boxworth, Cambs, Rosemaund, near Hereford and the Kent site on Romney Marsh, there are low numbers of apothecia present this week. Apothecia have also been found in winter wheat after winter oilseed rape with sclerotinia in 2007 in The Thames valley area. It is now a good time to look for apothecia in winter cereal crops where you know there have been sclerotinia problems in previous years. Sclerotinia spores are likely to be able to spread from infested cereal fields to nearby oilseed rape crops. Finding apothecia nearby would justify fungicide treatment on oilseed rape.
The first petal tests are now starting to be completed. They indicate that sclerotinia ascospores have been produced for at least three weeks and some crops are already risk despite low germination in depots. Crops in the Boxworth, Hereford and Romney Marsh areas have been tested for the first time during 2-15 April as first plants started to flower. Sclerotinia has been found at all the sites tested so far, mainly at low levels of 2.5-20% petals affected. However, at high risk sites in the Hereford area, interim results suggest higher levels of sclerotinia (35-65% petals affected) are present and fungicide treatment is now required. In other areas, it is likely that some crops may have 25% or more petals affected and justify treatment. At some sites, in previous years, 25% petal infection has resulted significant sclerotinia stem infection in crops and this is suggested as a guiding threshold. The sclerotinia risk is likely to keep increasing soil temperatures rise. Crops are early to mid-flowering should be treated where there is considered to be a sclerotinia risk. Fungicides give about 3 weeks protection and a second fungicide treatment may justified this season at high risk sites because of high crop value.
Rain during 23-24 April may be able to provide suitable conditions for some early leaf and stem infection by sclerotinia. If this occurs, some stem symptoms should be evident by mid-May.
Light leaf spot is present on the upper leaves and occasionally on stems, particularly in the north and west. It will now be difficult to control but protection of pods against light leaf spot should be part of decision making on products at PGR and sclerotinia timings
- Sclerotinia monitoring 2008 - 16 April (83.22 KB)
Published Date: Wednesday 16th April 2008
Crops have developed slowly during the last week and are still mainly between the yellow bud and early flowering stages. Some forward crops are close to the mid-flowering stage. The percentage of plants starting to flower is very variable and at least 50% plants should have flowers before the crop is considered at the early flowering growth stage. Where there is pigeon damage in significant parts of the field, the damaged areas should treated as a different crop for fertiliser and pesticide treatment.
Sclerotinia germination has started this week at both ADAS Boxworth and at the Kent site on Romney Marsh. Apothecia recorded at ADAS Rosemaund last week have disappeared. No germination has occurred so far at the other two sites. The first petal test has been completed on a crop in the Boxworth area and it showed 12.5% petals with sclerotinia. This indicates that sclerotinia spores have been produced for at least two weeks and some crops are already risk despite low germination in depots. (At some sites previously, 25% petal infection has resulted significant sclerotinia infection in crops.) The sclerotinia risk is likely to keep increasing soil temperatures rise. Crops are early to mid-flowering should be treated where there is considered to be a sclerotinia risk. Fungicides give about 3 weeks protection and a second fungicide treatment may justified this season at high risk sites because of high crop value.
Light leaf spot is present at high levels in some crops in all regions and is most prevalent in the north and west. It will now be difficult to control but should be part of decision making on products at PGR and sclerotinia timings.
- 9_apr-08 bulletin (82.28 KB)
Published Date: Wednesday 09th April 2008
Crops are mainly between the yellow bud stage and early flowering stages with some crops in the north and late crops in other regions still at the mid-stem extension stage. The percentage of plants starting to flower is very variable and at least 50% plants should have flowers before the crop is considered at the early flowering growth stage. Pigeon damage is severe in many fields or parts of fields and decisions should be made about whether to treat these areas as different crops for fertiliser and pesticide treatment.
Light leaf spot is present at high levels in some crops in all regions and is most prevalent in the north and west. It will now be difficult to control but should be part of decision making on products at PGR and sclerotinia timings. A threshold of 15-20% plants with light leaf spot is suggested this year because of the increased value of rapeseed. Phoma leaf spot is common and the first stem cankers can be found. No treatment is advised at this stage.
Sclerotinia germination has re-started at ADAS Rosemaund this week with 3% new germination. No germination has occurred so far at the other 4 sites. Soils are moist on the surface in many areas and sclerotinia activity should increase as soil temperatures rise. At present the sclerotinia risk is low. There is no need to rush to spray crops as sclerotinia risk is likely to increase later in April and into May and fungicides give only about 3 weeks protection.
- BASF / ADAS Sclerotinia Monitoring 21/03/08 (23.00 KB)
Published Date: Friday 21st March 2008
Crops are growing strongly after early nitrogen treatment and forward crops are close to the mid stem extension stage (30-50cm tall), with a low percentage of taller plants starting to flower. A few forward crops are ready for PGR treatment.
Light leaf spot is present in the north and west particularly where a winter spray was missed. It should be tackled early, by start of stem extension, with a non-PGR triazole at a threshold of 15-20% plants. (This is a lower threshold than last year because of the increased value of rapeseed). The threshold increases at later growth stages due to lower yield loss - 25% at mid-stem extension and 30% at yellow bud.
Phoma leaf spot is common but it is too late to achieve good control of stem canker.
Sclerotinia germination has started early this season with the first occurrence at ADAS Rosemaund last week. No new germination has occurred this week and at present the sclerotinia risk is low. Soils are moist on the surface in many areas and sclerotinia activity should increase as soil temperatures rise.
- BASF / ADAS Sclerotinia Monitoring 14/03/08 (31.06 KB)
Published Date: Friday 14th March 2008
Crops are growing strongly after early nitrogen treatment and forward crops are close to the mid stem extension stage (30-50cm tall), with a low percentage of taller plants starting to
flower. A few forward crops are ready for PGR treatment. Where crops were established late in the autumn, small plants are making only weak growth. There is continuing pigeon damage and this needs urgent attention or some crops will not recover. Light leaf spot is
producing new lesions at the moment and is still an underestimated threat - capable of causing yield losses of up to 1.0 t/ha. Prompt action is required to control light leaf spot where crops have 15-20% plants affected. (This is a lower threshold than last year because
the increased value of rapeseed).
Sclerotinia germination has started early this season and the first occurrence has been at ADAS Rosemaund this week. There have been occasional reports of sclerotinia activity on leaves during the winter. Look for plants where leaves are rotting and showing white immature sclerotia and some black sclerotia.
At present the sclerotinia risk is low. Soils are moist on the surface in many areas and sclerotinia activity should increase as soil temperatures rise.
 BASF/ADAS Sclerotinia Monitoring Bulletin 250507 (114.18 KB)
Published Date: Tuesday 05th June 2007
Sharp increase in Sclerotia germination – risk to late flowering winter crops and spring rape crops. Continued unsettled weather will increase the risk of Alternaria and secondary spread of Sclerotinia particularly in crops at risk of lodging
- BASF/ADAS Sclerotinia Monitoring Bulletin 150507 (112.13 KB)
Published Date: Wednesday 16th May 2007
For crops at the end of flowering, the Sclerotinia risk is much reduced. Sclerotinia could still be infecting some crops that are at the late flowering stage, particularly since cooler temperatures may prolong flowering. The risks of Alternaria will increase if showery weather continues and lodged crops may justify a late fungicide spray. Some Sclerotinia stem rot is evident in the West Midlands and Hereford area where rainfall enabled infection to take place in mid to late April. Powdery Mildew is now increasing rapidly. Stem canker symptoms have become much more common recently and high levels are present already on untreated susceptible varieties.
- BASF/ADAS Sclerotinia Monitoring Bulletin 270407 (111.10 KB)
Published Date: Tuesday 01st May 2007
Crops are now at mid- to late flowering, with many pods present. Final decisions are required as flowering will be almost complete in 2-3 weeks time with its duration dependent on the extent of flowering on branches. Some crops should reach the end of flowering in
1-2 weeks time. Crop height is variable and mainly in the range 120-180 cm tall. There is uneven growth and vigour in many crops with poorer areas often showing a blotchy or mottled leaf colour.
- BASF/ADAS Sclerotinia Monitoring Bulletin 070420 (109.57 KB)
Published Date: Friday 20th April 2007
Many crops are at the mid-flowering stage, with some pods present. Forward crops and early flowering varieties are at the late flowering stage on the main raceme. The duration of flowering will depend on the extent of flowering on branches. Some crops should reach the end of flowering in 2-3 weeks time. There is uneven growth and development in many crops, the poorer areas have been showing much less flower during the last week.
- BASF/ADAS Sclerotinia Monitoring130407 (105.98 KB)
Published Date: Friday 13th April 2007
Many crops are overall yellow, with plants mostly at early flowering. A few forward crops are at mid flowering and have pods can be seen on the main raceme. Backward crops are still green, but will soon be flowering.
- BASF/ADAS Sclerotinia Monitoring 060407 (99.33 KB)
Published Date: Friday 06th April 2007
Cool and generally dry conditions have resulted in uneven plant development in many crops. Many crops have flowering plants and some fields are overall yellow, but this masks a high proportion of shorter plants that are approaching the yellow bud stage. Crops will change quickly as they take up nitrogen.
- BASF_ADAS Sclerotinia Monitoring Bulletin 20070330 (36.10 KB)
Published Date: Friday 30th March 2007
Crop development has continued steadily during the last week despite cold nights. Most crops range from mid-stem extension stage (40-60cm tall) to the yellow bud stage (GS 3,3-3,7) with a low percentage of taller plants starting to flower. A few forward crops are flowering (GS 4,1). There are still some nitrogen and some plant growth regulator (PGR) treatments to be applied. Crops will change quickly as they take up nitrogen and decisions with PGR treatments may need to be made when this occurs.
- BASF_ADAS Sclerotinia Monitoring 20070323 (97.79 KB)
Published Date: Friday 23rd March 2007
Crop development has continued despite frosts and snow showers. Most crops range from mid stem extension stage (30-50cm tall) to the yellow bud stage, with a low percentage of taller plants starting to flower. Ground conditions have improved allowing nitrogen and some canopy management treatments to be applied. Crops will change quickly as they take up nitrogen and decisions with canopy management treatments may need to be made when this occurs.
- BASF_ADAS Sclerotinia Monitoring 20070316 (95.23 KB)
Published Date: Friday 16th March 2007
Crops are more advanced than usual this year, and about four weeks ahead of last year. Many crops are close to the mid stem extension stage (30-50cm tall) with a low percentage of taller plants starting to flower. A few forward crops have been flowering for more than a week. Ground conditions have been very wet and this has prevented applications of fertiliser and crop protection products to crops. Drier weather last week has enabled some nitrogen to be applied and the next decision will be canopy management treatments.
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