A ProMED-mail post
ProMED-mail is a program of the
Date: Fri 27 Apr 2012
Source: Pan European Networks [edited]
_Sclerotinia subarctica_, a fungus usually found in subarctic climates and which is known to affect both crops and wild plants, has been found in carrots and meadow buttercups for the 1st time in the UK as far south as Herefordshire.
_S. subarctica_ was found in Britain by plant scientists at the University of Warwick [UW]. [It] is closely related to _Sclerotinia sclerotiorum_, which commonly causes disease in crop plants such as lettuce, carrot and oilseed rape.
Dr John Clarkson, UW, said: "Our research raises interesting questions about how widespread this disease is, as it has previously only been reported in very cold climates such as Alaska and Norway. However, it's further south than originally suggested. By studying _S.
subarctica_ on meadow buttercups and crop plants, we have a great opportunity to find out more about its epidemiology. Further research needs to be done on understanding this disease and the potential threat it poses to agriculture in the UK."
[_Sclerotinia subarctica_ (synonym Sclerotinia species 1) is a provisional name, a formal description, and host range of the pathogen has not yet been published. The fungus has been reported to cause white mould disease on vegetable crops in Alaska, very similar to its close relative _S. sclerotiorum_.
_S. sclerotiorum_ can affect many different hosts causing varying symptoms. For example, it causes severe root rot on carrot as well as white mould of oilseed rape and soybean. _S. sclerotiorum_ is primarily soil-borne and can survive in soil as sclerotia. It is also spread by infected plant material, mechanical means, and wind-borne spores. Risk of crop infection depends on the previous disease history of an area as well as weather conditions. Disease management includes cultural practices and fungicide applications.
White mould of oilseed rape is one of the major diseases of the crop in the UK. Infection of oilseed rape by _S. subarctica_ has been demonstrated (see photos below) with symptoms similar to _S.
sclerotiorum_. It is suggested that, since symptoms of the 2 pathogens are very similar, _S. subarctica_ may possibly be widespread but undetected in sclerotinia-diseased crops in the UK. Further work to establish its distribution on crops and wild hosts is needed, but its presence on the buttercups (_Ranunculus acris_) suggests that local wild species may serve as pathogen reservoirs.
The significance of the presence of _S. subarctica_ in the UK needs to be assessed, but its discovery suggests that it may also be present elsewhere. Crop-pathogen systems are complex, and it is essential to identify the different factors involved in disease development so that pathogens can be controlled effectively. Consequently, the finding reported above may have implications for management of white mould diseases and resistance breeding of oilseed rape and other crop hosts in the UK and elsewhere.
UK (with counties):
_S. subarctica_ affected buttercup flower:
_S. subarctica_ symptoms on inoculated oilseed rape:
Sclerotinia field infections of white mould on oilseed rape:
Sclerotinia disease on carrot:
Sclerotinia disease on lettuce:
Additional news stories:
Information on _S. subarctica_:
First report of _S. subarctica_ in UK:
_S. subarctica_ preliminary taxonomy:
Information on _S. sclerotiorum_:
Sclerotinia disease on carrots:
White mould of oilseed rape:
_S. sclerotiorum_ taxonomy:
A HealthMap/ProMED-mail map can be accessed at:
Sclerotinia, sunflower - Canada: (MB) 20091224.4327 Sclerotinia, oilseed rape - Australia: (WA) 20091126.4062 White mould, soybean - USA 20091008.3481 Fungal diseases, soybean - USA 20090817.2912
Vegetable diseases - UK 20081225.4066
Sclerotinia, sunflower - Canada: (MB) 20081106.3490 Sclerotinia, multicrop - UK 20081008.3187 Fungal diseases, wheat, oilseed rape - UK 20080930.3083 Verticillium wilt & sclerotinia, oilseed rape - UK 20080718.2180 Wheat stripe rust, oilseed rape sclerotinia - China 20080408.1297 Fungal diseases, potato - Bangladesh 20080107.0091
Sclerotinia blight, peanut - USA (TX) 20041001.2702
Sclerotinia minor, chickpea - Australia (Qld) 20030625.1565
Sclerotinia spp., sunflower wilt - Spain 20020706.4677
Sclerotinia shoot blight, grapevine - Chile 20011103.2724
Crop diseases - Canada (Manitoba) 19990816.1417]