A LABORATORY funded by the University of Alicante has devised an ingenious way to combat the voracious alien insect that has killed thousands of palm trees across Spain and is resistant to pesticides.
Glen Biotech, in collaboration with Catalan robotics consultants Dronics Innovation are piloting a system they are calling ‘drone therapy,’ whereby a flying robot is seeded with a type of fungus which is delivered to the plant by an elastic tube and causes the tree to activate its natural defence system.
“It’s like a vaccine, the immune system acts as a defence and prevents the beetle from proliferating,” says agricultural engineer Rafael Lopez.
The pioneering team tested out 10 different fungi in their search for a treatment that might combat the beastly Asian palm weevil, which has been advancing westwards rapidly since the 1980s and has decimated Spanish palm populations.
Damage is chiefly caused by the larvae, which initially feed on soft fibres and bud tissues, but move towards the interior of the tree just before they pupate, excavating tunnels and large cavities, with the damage only tending to become visible long after infection.
A breakthrough was made when they discovered a particular fungus at the base of a palm tree, and after cultivating it inside rice grains, they found that it could offer a natural form of protection for the palms.
“Without the drones we would never have been able to deliver the fungus to a 12-metre-high palm, especially on windy days,” says Lopez. “The drone can deposit up to one-and-a-half kilos of vaccine to the top of each tree with pinpoint accuracy.”
The five-kilo drone is able to treat up to 140 palms per day, with each unit costing between €7,000-10,000, and trials conducted at the Abanilla palm grove, Spain’s second largest, have proven extremely successful and drawn interest from a number of countries.
Now, the team, are waiting to see what happens with a draft law which was recently submitted to Spanish parliament, and would permit night-time drone flights in urban areas, which is currently restricted.
This would allow treatment of urban palms such as those in the enormous Elche grove which contains over 200,000 individuals and was granted UNESCO World Heritage status in 2000.