Ergot on grass seed headDuring an early evening walk around Trelusback Farm near Stithians, on Monday 29th August 2011, I came across a number of Common Blue Butterflies – Polyommatus icarus settling down to roost amongst the tall grasses that had sprung up where volunteers from the Cornwall Butterly Conservation group had worked hard to expand a clearing during the late winter & early spring of 2011.

This area had been cleared of gorse and willows to allow Purple Moor Grass - Molinia caerulea and Devil’s Bit Scabious - Succisa pratensis to flourish, these being the key elements of prime habitat in which the rare Marsh Fritillary – Euphydryas aurinia can thrive. Although it is too early to tell if the management work will ultimately be successful in it’s aims, the signs are good with both plant species doing well. The Common Blue’s were certainly making good use of the location and were obvious candidates for a photograph.


Ergot on grass seed headI always think that the intricate golden sculptures of grass seed heads make great props so I was delighted to find one of the Blue’s perched nicely on a spike with no distracting background items in view. Of course when you look through the viewfinder at the macro world in front of you each tiny slice of life appears in far more detail and on this occasion the first thing that screamed out to me was that the grass head was far from golden. In fact it was speckled black with mould, and there amongst the seeds was a dark cigar shaped object which I knew of from a previous encounter in 2010.

Keith Wilson (the owner of the site) & Jo Poland from Cornwall Butterfly Conservation confirmed that what I had found was in fact an Ergot. Look closely at the lower left of the grass seed head just beneath the butterfly’s legs in the photo below and you should be able see one of the ergots.

Ergots are a group of fungi which grow on grasses, including cereal crops, and if ingested by humans or other animals, can have a poisonous effect on the central nervous system.

In the middle ages poisoning from rye bread that contained ergot infected grain was a major problem, resulting in gangrene, convulsions, hallucinations and even death.  In recent years there have been increasing problems of ergot contamination in wheat which it has been suggested is as a result of changes in farming systems, in particular the introduction of grass headers around arable fields. The theory is that flowering grasses in the margins of these fields will act as a reservoir for the fungi allowing the ergots to spread to the adjacent wheat crop. However given that it has been suggested that ergots like Claviceps purpurea are more likely to appear where very cold winters have preceded very wet summers perhaps it is just another sign of climate change?

Despite all this however there is another side to the story as Ergot derived drugs are now widely used in childbirth, migraine medications and some treatments for Parkinson’s Disease. It has also been used in the production of LSD!

Back to the butterflies, if you are interested in Cornish butterflies the Cornwall Butterfly Conservation group has an excellent website, maintained by Shaun Poland, that includes a lively forum. Amongst other things the forum contains news of any working parties taking place at locations such as Trelusback where volunteers help carry out management work to improve habitats for these beautiful insects. These events are really good fun and are an excellent way of keeping fit throughout the winter months. There are numerous butterfly populations at sites throughout the county that need a helping hand so new helpers are always welcome.

For further information checkout the news/events/workparties section of the forum at the CBC website here:  http://www.cornwall-butterfly-conservation.org.uk/index.html
Common Blue Butterfly