Sandy's Garden ... Drones

It is defined as ‘a continuous low humming sound’; it can be ‘a monotonous speech’; it might be ‘a continuous musical note of low pitch’; a further definition is ‘a male bee in a colony of social bees, which does no work but can fertilize a queen’; then again, by association with this definition from the apiarist’s world, a drone may be ‘a person who does no useful work and lives off others’; and finally, a drone is ‘a remote-controlled pilotless aircraft or missile’.

Gardeners are familiar with honey bees, although they may not be able to distinguish a drone … a male, which does no work … from a worker bee, a female of the species. The drone’s body is larger and his eyes are twice the size of a worker bee’s eyes; he lacks a sting and has just one function in life; he must be ready to fertilize a receptive queen, an act which results in his death. Nor can he claim that this sacrifice ensures the continuing existence of the hive, for the queen will attract numerous drones to her sex orgy and all die after their moment of glory. And, gentle reader, lest you suppose that any drones with an inadequate sex drive can lead the life of Riley while the womenfolk of the hive work themselves to death … quite literally … come the autumn they will be driven out of the hive to a certain death.

Apart from fertilising a queen bee, then, these drones do little for agriculture or for horticulture. But in early April, this erudite publication’s sister newspaper The Scotsman carried an intriguing story about the hoped-for benefits of the drone which is ‘a remote-controlled pilotless aircraft or missile’. “Drones to protect Scotland’s soft crops from fruit flies,” proclaimed the headline above the sub-heading, “Scientists at the University of Aberdeen are to use drones to identify fruit fly activity in Scotland’s soft fruit crops.” Filed by Shän Ross, the story continued by relating how scientists at the University of Aberdeen are pioneering the use of drones to monitor damage by the fruit fly Drosophila suzukii, also known as the spotted wing drosophila.

This little charmer is an Asian pest of fruit crops which has almost simultaneously been introduced into North America and in Italy (in 2008 and 2009, respectively). In 2012, it was reported in the United Kingdom and has since been found as far north as Dundee. It attacks many fruit crops, including strawberries, apples, raspberries and some blackberries – and that list is by no means complete. The relevance to Scotland is obvious, for Scottish soft fruit crops are an important component of Scottish horticulture. Soft fruit production has doubled over the past decade; and Scottish government figures show that the market value of these crops has trebled to £60-80 million per annum. We have been warned that up to 80 per cent of Scotland’s soft fruit industry could be lost unless this pest can be controlled, if not eradicated. That’s the commercial side; many gardeners also grow soft fruit and have reason to be concerned now that Drosophila suzukii has been reported right here in Scotland.

Dr David Green, of the University of Aberdeen, has explained: “Early detection is key to prevention. We are aiming to develop an automated system where drones fitted with cameras would fly over so-called ‘sticky traps’ which would trap the fly in a way that allows it to be identified from the air. From there a fast alert can be issued to growers and they can undertake the necessary action to prevent the destruction of their crop, which in many cases can amount to many thousands of pounds.” I suspect Dr Green’s ‘many thousands of pounds’ is a tad conservative; and I hope these drones work better than their honey bee namesakes.