Evaluation continues

Candidate

The white mould or Sclerotinia stem rot (SSR) disease, caused by Sclerotinia sclerotiorum, is one of the most important worldwide diseases in the oil crop Brassica napus. The pathogen overwinters as sclerotia in the soil or debris, which germinate and release ascospores which then infect the crop. They are weak pathogens and do not usually infect healthy plant tissue but invade through dead or injured tissue, or spent flower blossoms. Thus sclerotia infection of seed means they can be sown adjacent to seed and then have the potential to germinate within the susceptible crop. It has a wide host range and is widespread in the environment in weeds and other crops, and is controlled by crop rotation, isolation from other susceptible crops, fungicides and reduction of moisture and poor air circulation where possible.
Research has shown high numbers of ascospores in the air, e.g, 2007 had a severe SSR epidemic in England and high numbers of airborne ascospores were trapped at Rothamsted; while both 2003 and 2004 had a very low incidence of SSR in England and low numbers of airborne ascospores. The severe SSR season of 2007 occurred throughout a large part of Northern Europe and was not predicted in the UK by climate-based disease-forecasts (Atkins et al., 2008).
Seed samples have been found to contain up to 432 sclerotia per kilogram of the seed and sclerotia are reported to remain viable and virulent up to 7 years assuring pathogen availability when a host crop is planted.
Survival of the pathogen is also possible through infected seeds in the form of mycelial infection of the testa (Sharma et al., 2015).
The SEWG concluded that the relative significance of seed as a pathway depends on the level of inoculum already present in the soil, which is likely to vary across the EU depending on cropping history, practice of rotation etc. For some areas it is likely that seed could be a significant pathway of introduction to fields and places of production which are otherwise substantially free from the pathogen.

Yes

Frequent occurrences of the disease in mild to severe form have been reported from Denmark, Finland, France, Germany, Sweden and United Kingdom (Sharma et al., 2015). Yield losses in susceptible crops vary and may be as high as 100 per cent. The shattering of prematurely-ripened seed pods before harvest, and loss of quality in the form of smaller, shrunken and chaffy seeds has been observed. Reported yield loss estimates due to Sclerotinia rot (SR) in rapeseed varied from very heavy in Germany. In central and eastern parts of Finland, losses by SR were so great that the cultivation of rapeseed is considered beneficial only in the southern and western areas (Sharma et al., 2015).

Major

No

Candidate

Economic impact is considered major, subject to variation between the years.

candidate

Evaluation continues

Candidate

The white mould or Sclerotinia stem rot (SSR) disease, caused by Sclerotinia sclerotiorum, is one of the most important worldwide diseases in the oil crop Brassica rapa. The pathogen overwinters as sclerotia in the soil or debris, which germinate and release ascospores which then infect the crop. They are weak pathogens and do not usually infect healthy plant tissue but invade through dead or injured tissue, or spent flower blossoms. Thus sclerotia infection of seed means they can be sown adjacent to seed and then have the potential to germinate within the susceptible crop. It has a wide host range and is widespread in the environment in weeds and other crops, and is controlled by crop rotation, isolation from other susceptible crops, fungicides and reduction of moisture and poor air circulation where possible.
Research has shown high numbers of ascospores in the air, e.g, 2007 had a severe SSR epidemic in England and high numbers of airborne ascospores were trapped at Rothamsted; while both 2003 and 2004 had a very low incidence of SSR in England and low numbers of airborne ascospores. The severe SSR season of 2007 occurred throughout a large part of Northern Europe and was not predicted in the UK by climate-based disease-forecasts (Atkins et al., 2008).
Seed samples have been found to contain up to 432 sclerotia per kilogram of the seed and sclerotia are reported to remain viable and virulent up to 7 years assuring pathogen availability when a host crop is planted.
Survival of the pathogen is also possible through infected seeds in the form of mycelial infection of the testa (Sharma et al., 2015).
The SEWG concluded that the relative significance of seed as a pathway depends on the level of inoculum already present in the soil, which is likely to vary across the EU depending on cropping history, practice of rotation etc. For some areas it is likely that seed could be a significant pathway of introduction to fields and places of production which are otherwise substantially free from the pathogen.

Yes

Frequent occurrences of the disease in mild to severe form have been reported from Denmark, Finland, France, Germany, Sweden and United Kingdom (Sharma et al., 2015). Yield losses in susceptible crops vary and may be as high as 100 per cent. The shattering of prematurely-ripened seed pods before harvest, and loss of quality in the form of smaller, shrunken and chaffy seeds has been observed. Reported yield loss estimates due to Sclerotinia rot (SR) in rapeseed varied from very heavy in Germany. In central and eastern parts of Finland, losses by SR were so great that the cultivation of rapeseed is considered beneficial only in the southern and western areas (Sharma et al., 2015).

Major

No

Candidate

Economic impact is considered major, subject to variation between the years.

candidate

Evaluation continues

Candidate

Sclerotinia head rot or stem rot, caused by Sclerotinia sclerotiorum, is a significant disease of sunflower (Helianthus annuus L.) production in most of the world. Resistance is available in some varieties but no line or hybrid is immune to it. It attacks a wide range of field crops, including soybeans, field beans, oilseed rape and lupin as well as various vegetable crops. The pathogen can survive or overwinter as sclerotia in the soil or in field debris etc. and may survive for up to four years in the soil. In summer, when sunflower roots come in contact with the sclerotia, the sclerotia germinates and infects the roots and then grows into the taproot and forms a canker at the stem base. This infection prevents the plant from taking up water and nutrients. Adjacent plants may be infected by root-to-root contact with infected plants. If the overwintering sclerotia come to the surface via cultivation etc, or survival on other hosts nearby, then these can produce wind borne ascospores so infecting wider areas and casing a head rot. Management is by long rotation, deep burial, control of alternate hosts or use of resistant varieties (Flett B ARC-Grain crops Institute SA, 2012).
Sowing of seed contaminated with sclerotia will therefore also be a risk and there are tolerances for this in 2002/57/EC. In addition, seed can also be infected and transmitted to seedlings, so causing damping-off (Venturoso et al., 2015).
The SEWG concluded that the relative significance of seed as a pathway depends on the level of inoculum already present in the soil, which is likely to vary across the EU depending on cropping history, practice of rotation etc. For some areas it is likely that seed could be a significant pathway of introduction to fields and places of production which are otherwise substantially free from the pathogen.

Yes

Sclerotinia Head Rot (SHR) is one of the most damaging diseases of sunflower in Europe, Argentina, and USA, causing average yield reductions of 10 to 20%, but leading to total production loss under favorable environmental conditions for the pathogen (Fusari et al 2012). In Egypt, Sclerotinia wilt and head rot were found distributed through the entire surveyed sunflower production areas and average incidence of wilt was 6.7% and 9.9%, while head rot incidence was 1.3 and 1.9% in 1996 and 1997, respectively (El-Deeb et al., 2000). The inoculum density ranged from 0.04 to 0.15 sclerotia per kg soil, while wilt incidence ranged from 8.7 to 15.0% respectively, so showing a positive correlation between wilt incidence and inoculum density. Both diseases, Sclerotinia wilt and head rot, caused significant reduction in weight of 1000 seeds, seed yield per head and oil content, and head rot caused higher yield loss than wilt. In Croatia Sclerotinia sclerotiorum was the most dominant pathogen on sunflower stems in 2001 with percentage of infection of non-treated and fungicide-treated plants between 0 and 32.5%, and 0 and 17.5%, respectively (Ćosić et al., 2005).

Major

No

Candidate

Economic impact is considered major, subject to variation between the years.

candidate

Evaluation continues

Candidate

The white mould or Sclerotinia stem rot (SSR) disease, caused by Sclerotinia sclerotiorum, is an important worldwide diseases in the white mustard crop Sinapis alba, though it is less severe than some other brassica species. The pathogen overwinters as sclerotia in the soil or debris, which germinate and release ascospores which then infect the crop. They are weak pathogens and do not usually infect healthy plant tissue but invade through dead or injured tissue, or spent flower blossoms. Thus sclerotia contamination of seed means they can be sown adjacent to seed and then have the potential to germinate within the susceptible crop. It has a wide host range and is widespread in the environment in weeds and other crops, and is controlled by crop rotation, isolation from other susceptible crops, fungicides and reduction of moisture and and poor air circulation where possible.
Research has shown high numbers of ascospores in the air, e.g, 2007 had a severe SSR epidemic in England and high numbers of airborne ascospores were trapped at Rothamsted; while both 2003 and 2004 had a very low incidence of SSR in England and low numbers of airborne ascospores. The severe SSR season of 2007 occurred throughout a large part of Northern Europe and was not predicted in the UK by climate-based disease-forecasts (Atkins et al., 2008).
Seed samples have been found to contain up to 432 sclerotia per kilogram of the seed and sclerotia are reported to remain viable and virulent up to 7 years assuring pathogen availability when a host crop is planted.
Survival of the pathogen is also possible through infected seeds in the form of mycelial infection of the testa (Sharma et al., 2015).
The SEWG concluded that the relative significance of seed as a pathway depends on the level of inoculum already present in the soil, which is likely to vary across the EU depending on cropping history, practice of rotation etc. For some areas it is likely that seed could be a significant pathway of introduction to fields and places of production which are otherwise substantially free from the pathogen.

Yes

Frequent occurrences of the disease in mild to severe form have been reported from Denmark, Finland, France, Germany, Sweden and United Kingdom (Sharma et al., 2015) although no details are specific to Sinapis alba. However it is remarked moderate Sclerotinia resistance has been reported in this species. Yield losses in susceptible crops vary and may be as high as 100 per cent. The shattering of prematurely-ripened seed pods before harvest, and loss of quality in the form of smaller, shrunken and chaffy seeds has been observed. Reported yield loss estimates due to Sclerotinia rot (SR) in rapeseed varied from very heavy in Germany. In central and eastern parts of Finland, losses by SR were so great that the cultivation of rapeseed is considered beneficial only in the southern and western areas (Sharma et al., 2015).

Major

No

Candidate

Economic impact is considered major, subject to variation between the years.

candidate