Carrot Sclerotinia Germination Tool

Sclerotinia monitoring in carrots adds to successful disease control

Carrot Sclerotina Risk Assessment

Click on the image above to see the
Carrot Sclerotinia risk assessment decision guide.

The BASF and ADAS sponsored Sclerotinia monitoring system aims to help carrot growers assess their disease risk and so plan an effective control programme. Weekly results will be available to growers and advisors on this site.

Dr. Peter Gladders from ADAS Boxworth explains how the monitoring works. “The Sclerotinia pathogen survives in the soil as resting bodies or sclerotia, which can remain viable for up to ten years and which germinate when conditions are favourable. This is when soil is moist and temperatures are between 5°C- 25°C, with optimum temperatures being 15°C-25°C. The fungus then invades diseased, senescent or decaying leaves, particularly those in contact with moist soils. The roots are infected via the leaf petioles and through the crown.”

The Sclerotinia monitoring system gauges the germination pattern of sclerotia and monitors germination weekly throughout June to August. As sclerotia provide the source of infection within the carrot crop, this indicates the extent of the Sclerotinia risk and the need for fungicide treatment. Growers should keep checking the published information on agriCentre and be ready to take action,” Dr. Gladders explains.

Dr Gladders notes that Sclerotinia has become a much more widespread and serious disease in many crops including carrots, oilseed rape, brassicas, peas and beans. “As a consequence carrot growers are starting their programmes earlier and using more robust fungicide programmes right from the start. It is particularly important to get the first fungicide spray on early before the foliage has a chance to close over and starts to senesce. Once present in the crop, there is no curative solution to the disease,” he says.

Sclerotinia Monitoring Bulletins 2009

14th August 2009 - Germination of the sclerotia of sclerotinia has increased again in carrot crops during the last week. Some crop infection has started in crops in Nottinghamshire and Scotland, but is being contained by fungicide treatments. There is a very high risk of infection where crops have senescent leaves as the weather remains unsettled. Sclerotinia sprays should be scheduled regularly to ensure leaves are protected against early infection and secondary spread.

6th August 2009 - Germination of the sclerotia of sclerotinia has increased again in carrot crops during the last week. Some crop infection has started in crops in Nottinghamshire and Scotland. There is a very high risk of infection where crops have senescent leaves as the weather remains unsettled. Sclerotinia sprays should be scheduled regularly to ensure leaves are protected against early infection.

30th July 2009 - Germination of the sclerotia of sclerotinia has increased in carrot crops during the last week. Some crop infection has started in Scotland. There is a high risk of infection as the weather remains unsettled and senescent leaves are present in many crops. Sclerotinia sprays should be scheduled regularly to ensure leaves are protected against early infection.

24th July 2009 - Sclerotinia is now germinating at the all the monitoring sites. Recent rainfall and good ground cover by carrot crops have provided favourable conditions for apothecial production. With continuing unsettled weather, the risk of infection in carrots is increasing significantly now. Sclerotinia sprays should be scheduled regularly to ensure leaves are protected against early infection.

17th July 2009 - The first germination of sclerotia of Sclerotinia has been recorded in Nottinghamshire this week. There is also activity in Scotland. With unsettled weather and good ground cover, the risk of infection in carrots is increasing. Where soils are moist for several days after irrigation or rain, sclerotinia could now germinate rapidly in carrot crops. Sclerotinia sprays should be scheduled regularly from just before canopy closure.

10th July 2009 - Sclerotinia activity is still low, but crops are at a susceptible stage as cotyledons and young leaves start to senesce. Where soils are moist for several days after irrigation or rain, sclerotinia could now germinate rapidly in carrot crops. Sclerotinia sprays should be scheduled regularly from just before canopy closure.

3rd July 2009 - Sclerotinia activity is low in the current hot dry weather. Where soils are moist for several days after irrigation or rain, sclerotinia could now germinate rapidly in carrot crops. The first sclerotinia spray should be applied just before canopy closure.

26th June 2009 - Sclerotinia is showing low germination at present in winter arable crops and is being restricted by dry weather. Where soils are moist sclerotinia may germinate soon in April or early May sown carrot crops. The first sclerotinia spray should be applied just before canopy closure.

19th June 2009 - Sclerotinia is showing low germination at present in winter arable crops and is being restricted by dry weather. Cooler weather with more frequent rainfall or irrigation could allow sclerotinia to germinate soon in April or early May sown carrot crops.

9th June 2009 - Sclerotinia is showing low germination at present in winter arable crops but it has responded to recent heavy rainfall. Cooler weather with more frequent rainfall or irrigation could allow sclerotinia to germinate soon in April or early May sown carrot crops.

5th June 2009 - Sclerotinia germination is low at present in winter arable crop because of dry soil conditions. Cooler weather with more frequent rainfall or irrigation could allow sclerotinia to germinate in April or early May sown carrot crops.

Using Signum® in Carrots

The key to the successful use of Signum® in carrots is timing. Both active ingredients in Signum® (boscalid and pyraclostrobin) are excellent protectants, and both need to be placed at the base of the crop where infections of Sclerotinia start. Timely application ensures protection of the leaves before infection can take place.

Prolonged protection can be obtained by applying a second spray of Signum® (following an application of a fungicide with an alternative mode of action). This second Signum® application will also be best placed early in the crop cycle and will ensure the continued advantage of the strong protectant and physiological properties of Signum® and help prevent dead leaf material becoming a food source for Sclerotinia.

Control of Alternaria and Powdery mildew prevent dead leaves becoming a nutrient source for Sclerotinia. Signum® has shown excellent activity on both Alternaria and Powdery mildew.

Note that Signum® contains a QoI inhibiting fungicide, ensure that the FRAC guidelines for fungicide resistance management are followed.

If you have any queries or require further information, please do not hesitate to contact your local Agronomy Manager or the BASF Technical Services Hotline 0845 602 2553 .

PRODUCT LABEL
SAFETY DATA SHEET
ENVIRONMENTAL INFORMATION SHEET

® = Registered trademark of BASF.
Signum contains contains boscalid + pyraclostrobin.

ALWAYS READ THE LABEL. USE PESTICIDES SAFELY.

Archive

13th August 2008 - The crop is now at the 10 leaf stage with 100% ground cover with at least two dead leaves per plant now evident.

6th August 2008 - The crop is now at the 10 leaf stage with 100% ground cover with at least two dead leaves per plant now evident.

30th July 2008 - The crop is now at the 10 leaf stage with 100% ground cover with two dead leaves per plant now evident.

26th July 2008 - The crop is now at the 10 leaf stage with 100% ground cover with the first dead leaves now evident.

16th July 2008 - The crop is now at the 8 leaf stage with 100% ground cover but leaf senescence is now starting.

9th July 2008 - The crop is now at the 8 leaf stage with 87% ground cover.

2nd July 2008 - The crop is now at the 7 leaf stage.

25th June 2008 - The crop is now at the 6 leaf stage.

17th June 2008 - The crop is now at the 5 leaf stage.

10th June 2008 - The crop is now at the 4 leaf stage.