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Blandford’s ‘Most pernicious beast’

The early part of every summer for the last four decades has been spoilt for many Blandfordians by the arrival of a fly with a very nasty bite. Colin Trueman tries to find some truth among the many legends about the ‘Blandford Fly’.

❱ The beast: a female Simulium posticatum, alias the Blandford Fly (Dr Mike Ladle)

❱ The beast: a female Simulium posticatum, alias the Blandford Fly (Dr Mike Ladle)

‘God in His wisdom made the fly,
And then forgot to tell us why.’

Ogden Nash’s epigram, or words to its effect, are very much in the minds of the residents of Blandford in May and June. For this is the ‘biting season’ of the much feared and greatly loathed Blandford Fly, whose bite causes severe irritation, pain, swelling and blistering, frequently necessitating visits to the doctor and sometimes to hospital. It is an insect of the blackfly type which, in search of human blood to nourish its eggs, bites into the first expanse of exposed human skin it encounters. Victims experience a sharp stabbing sensation as the fly’s saliva enters the wound, and the pain then increases and can last for weeks.
In 2014, however, the dreaded insect unexpectedly made its presence felt towards the end of the summer, making headlines in the Dorset press. This was not because of a second wave of attacks on the population, but because of the huge response to a petition urging the authorities to continue treatment of the River Stour to control the fly. More than two and a half thousand people signed the petition over a period of eight weeks, demonstrating the strength of feeling which this pest inspires.
The petition was started by Blandford resident Pat Ashworth, an octogenarian with an energy which belies her age. She had seen an alarming headline in Forum Focus, Blandford’s free monthly newspaper, which read: ‘Fly bite victim’s anger over cuts to funding’. Accompanying the article was an alarming picture, in full colour, of the badly bitten leg of a victim. Pat was shocked to read of the withdrawal of funding for treatment of the River Stour to control the fly by spraying its habitat with a biocide. Her first thought was: ‘Somebody ought to do something about this!’ Her second thought was: ‘Why not me?’ Within an hour she had downloaded some petition forms from the internet.
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❱ A bite from the Blandford Fly can produce very unpleasant wounds and painful swellings

A bite from the Blandford Fly can produce very unpleasant wounds and painful swellings

‘I could have made it an on-line petition,’ says Pat, ‘but I preferred the old-fashioned pen-and-paper variety, as it was a local matter and I didn’t want people from far afield joining in. I stood on street corners and river bridges and went into shops, pubs and offices, and along the way spoke to dozens of people. I started in August and went on until October and collected 2473 signatures.’
It is said that even if a Blandfordian has not been bitten himself, he knows someone who has been; a high proportion of those who signed made comments which bore out the truth of that claim. Pat points out that the health aspect affects not only the victims, some of whom may be off work for some time or at least severely incapacitated, but also the local surgeries, who are already overstretched and do not need an influx of extra appointments during this particular period of late spring and early summer.
Another issue which concerned Pat Ashworth was the negative coverage in the press which the Fly brings to Blandford. ‘At a time when tourism brings considerable income for many small businesses along the river,’ she says, ‘continued publicity about “the return of the Fly” is not to be welcomed. It’s unfortunate for us that this particular species of blackfly was christened with the title “Blandford”. It occurs all along the River Stour and could quite as well have been called the Wimborne Fly – or whatever!’

❱ Pat Ashworth presents her petition to North Dorset DC on 13 November 2014

❱ Pat Ashworth presents her petition to North Dorset DC on 13 November 2014

Pat duly presented the petition to North Dorset District Council at their headquarters in Blandford on 13 November last year. Present at the occasion were NDDC Chief Executive Liz Goodall, who promised to forward the petition to the Dorset Health Protection Network, and Gary Jefferson, NDDC Cabinet Member for Health, who gave the reassurance that NDDC would continue funding its share of the cost of the treatment of the River Stour in March 2015.
Pat’s petition certainly drew attention to the Blandford Fly problem. Local magazine Forum Focus monitored progress in every edition for the rest of the year, and Pat gratefully acknowledges the support of its editor, Nicci Brown. But it turns out that the problem is far from a simple one. It is not only NDDC which contributes to the funding of the spray treatment; other authorities neighbouring the Stour also contribute to the overall cost of around £12,000. In 2012 NHS Dorset threatened to withdraw its contribution, saying that the treatment was not a public health priority, and Christchurch and East Dorset district councils and Poole Borough Council all indicated that they could not contribute to the shortfall, and the general feeling was that Public Health England should were the responsible authority. But in December 2014 the Dorset Health Protection Network, whose members include the authorities funding the annual treatment, agreed to support NDDC in funding the spraying in 2015 – if the necessary approval can be obtained: and here is another problem.

The River Stour at Blandford looks tranquil and picturesque, but its banks are the nesting places of the Blandford Fly

The River Stour at Blandford looks tranquil and picturesque, but its banks are the nesting places of the Blandford Fly

The EU has introduced a new licensing regime for the chemical used to treat the river, and the company that manufactures it has had to apply for a new licence. But due to ‘a backlog in dealing with these applications’ (EU-speak for ‘our bureaucracy moves at a speed which makes continental drift seem like a 100-metre sprint’), the licence is unlikely to be granted in time to allow the usual treatment in March 2015. Given a quagmire like this, it is unsurprising that definite statements from official representatives are hard to come by at the moment.
It is worthwhile stepping back and taking an overall view of this pest. It first appeared as far back as the 1960s, but it was in 1972 that about 600 people visited their doctors in Blandford complaining of a particularly nasty insect bite. It turned out that these bites came from an insect which had not previously plagued our country: a blackfly now known as Simulium posticatum. There are many legends which allege to account for its arrival, the most colourful being that a student from Bryanston School came back from a holiday in South America with one of the flies in a jam jar and left it in the science laboratory, where a cleaning lady knocked the jar onto the floor, breaking it and releasing the fly. Another legend says that the insect came in as eggs in African mud caked on the boots of soldiers returning from the Congo to Blandford Camp. Both versions sound rather less likely than the plot of Jurassic Park; the truth is that it is a widespread northern European species which has long been present in some of the rivers of south-east England.

Dr Mike Ladle is a biologist and a Fellow of the Freshwater Biological Association at Wareham. He has a deep knowledge of insects, he is a fisherman who knows the local waters personally, and – most importantly – he himself has been bitten by the fly.
According to Dr Ladle, the females of Simulium posticatum need a blood meal to mature their two to three hundred eggs. Eggs are laid in summer in the crevices of vertical banks with overhead tree cover; the larvae, in the various stages of growth, cling to the weeds but can only live where there is a strong flow of water which they then filter for nutriment. When the egg-laying sites were first discovered, the possibility of mechanical egg removal was assessed: four million eggs were scraped from ten metres of river bank, but the task of treating 25 miles of river in a similar way was too daunting.
It was not until the 1980s that a newly discovered bacterium from the Negev desert in Israel, Bacillus thuringiensis israelensis, was suggested by Dr Ladle as a potential solution to the problem. This bacterium produces spores containing certain enzymes which, when eaten by the larvae of the Blandford Fly, destroy their gut walls and kill them. Just as importantly, it does not kill the larvae of any other species of blackfly – blackflies are a key element of the river ecosystem and there are plenty of other creatures which feed on them, so it would have been absurd to wipe them out to save people from being bitten.
The first large-scale treatment of the river took place in 1991, and it worked. Whereas about 1400 people had sought treatment for fly bites in 1988, this was down to 45 in 1999. Dr Ladle has said that ‘this is probably the best example of the use of a biological agent to control a pest, in an ecologically friendly fashion, anywhere in the world.’

Such is the unpopularity of the Blandford Fly that its effigy has taken the place of Guy Fawkes in some parts of the country (picture credit: Martin Wainwright)

Such is the unpopularity of the Blandford Fly that its effigy has taken the place of Guy Fawkes in some parts of the country (picture credit: Martin Wainwright)

Regrettably, the Blandford Fly has become known over much of England – there are reports of bites blamed on it from Herefordshire to Hertfordshire – and one Oxford resident, the journalist (and insect fan) Martin Wainwright, burned an effigy of the fly on Guy Fawkes’ Night in revenge for its savage bites in their part of the world.
The fly has even come to the notice of the House of Lords. In a debate on the subject, Lord Campbell of Croy asked: ‘My Lords, can my noble friend assure us that this fly, which sounds most pernicious, is neither a threatened nor protected species?’ To which the Earl of Dundee replied: ‘No, my Lords, the fewer the better.’ All of Blandford is with him on that. ◗

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