"The only real solution is to develop self-pollinating varieties of apple," says William Barnett, manager of Tillington Fruit Farm in Herefordshire. "But to do this we should have started work 40 years ago - now we are stuck with a terrible problem."
The villain is a tiny mite, varroa, which originated in South East Asia where it lives harmlessly on a native wild bee. Around the turn of the century, however, it managed to transfer hosts to the honey bee, Apis mellifica mellifera, which had been imported by European imperalists. From there it slowly leap-frogged back through colonies across Asia until, in 1992, it was first noticed in Devon.
What it lacked in speed arriving, it has made up with the ferocity of its impact. Although at first an infected hive shows few signs of damage, after about three years the colony collapses under the combined pressures of falling reproduction and secondary viral infections. Last year's warm weather helped the mites increase - a problem compounded by the cold winter which further weakened host colonies.
As a result, varroa is now sweeping across southern England and reports of the parasite are also coming in from Wales and as far north as Cumbria. The mite appears to be causing the most devastation in the south east.
"Around my home in Sittingbourne, losses among local bee hobbyists are 100 per cent," says Mr Williams. "Commercial keepers have lost fewer, but we're still talking about 80 per cent."
A partial cure is possible if varroa mites are detected early enough. However, this involves insecticides which for obvious reasons have to be used in minute doses. Consequently, an infected colony can never be completely cleared of the pest and even if it were, once the mite is established locally, the colony would be open to reinfection from untreated local hives. Soon all colonies will have to be treated regularly or face extinction.
This could mean the end one of the oldest forms of farming. Bees have been exploited for honey for thousands of years, but increasingly have become valued more for their beneficial by-product: pollination, necessary to transform flowers or blossom to seed and fruit.
Although wind and wild bees can also perform the task, Brian Stenhouse, general secretary of the BFA says domesticated honey bees are easily the best pollinators. "Not only are there far more of them than wild insects at the vital time of year, but once they latch on to a pollen supply, they stay with it," he says. A typical hive, which starts the year with 35,000 bees, will systematically milk an orchard of pollen before turning to alternatives. In comparison, the tiny colonies of bumble bees (any "wild" honey bees are really feral colonies which have swarmed) are inefficient, wandering randomly from hedgerow flowers to blossom.
"Bees are vital for pollination - particularly in cold weather such as the spring we've just had," says Janet Chapman, an apple farmer in Gloucestershire.
Not surprisingly, the disappearance of honey bees has worrying implications for agriculture: "Our local apple farmers are beginning to panic," points out Mr Williams of the BFA. As pollination secretary he liaises between hive owners and farmers, administering bee contracts where fruit farmers hire colonies from professionals at pounds 25 a hive for the month trees are blossoming. "Traditionally they might rely on a couple of hobbyist hives," he says. "These would be helped out by contracting in more for the pollination period, but this spring there are almost no bees at all in many orchards, and farmers are finding they can't get hold of alternative supplies."
The effects could also be serious for oil seed rape growers where bees are not essential, but greatly speed up pollination. This ensures an even seed set, with the result that everything ripens at the same point. As a consequence, Britain's 350 professional bee keepers are in constant demand throughout the summer, shuttling their 35,000 hives between strawberries, beans, commercial greenhouses and rape fields. The process culminates with the heather contracts in late summer and the Ministry of Agriculture, Fisheries and Food advises fruit farmers to provide one hive per acre in apple orchards, rising to four in the more insect-dependent cherry orchards. Although no one can put a firm value on this work, one estimate puts it at pounds 900m every year (in contrast, the honey is only worth pounds 15- 20m)
Now a wide range of crops whose success is based on natural pollination are under threat. "Every one of my 300 colonies in Kent is affected, although my 150 Scottish hives are still clear," confirms Mr Stenhouse. "I'm lucky not to have lost any, but I'm almost unique - I know one farmer who's lost all but 19 of his 400 colonies."
Others are still fighting hard: "I'm taking steps to guard against the danger," says fruit farmer Mr Barnett who keeps 20 hives of his own. "I won't touch anyone else's swarms and won't allow hives from outside on to the farm." He adds, however, that varroa has been found just to the south and east and admits he is probably struggling against an unstoppable tide.
Further west, Pam Gregory, bee inspector for Wales, is resigned to the parasite's arrival. Because sheep and cattle are the mainstays of local farmers, agriculture is unlikely to be as hard hit as in England, but she says ordinary gardeners face falling yields: "There's no doubt bees make a difference - I know, for example, my broad and runner bean crop is much better thanks to local hives." Far more important, however, is the potential damage to wildlife. "Bees are vital pollinators for many wild flowers and trees," she says. "Without them, many nuts and berries will fail and the effects on birds and animals could be terrible."