Linda Presley

Inside, Dr Landa and her team keep a collection of deadly strains of the Xylella microbe.

And the big fear, of course, especially here in Andalusia, is the olive industry.

Xylella kills slowly, clogging the vessels through which a plant absorbs water. And the only way it spreads is through insect vectors. They feed on an infected tree, then carry the microbes to the next tree they land on. It's believed Xylella first arrived in Europe in ornamental coffee plants from Latin America.

Dr Landa remembers her first sight of the havoc wreaked by the killer bacterium when she visited southern Italy in 2014.

The dying trees generated conspiracy theories. Scientists, an oil pipeline, large companies, even the mafia, all of them were blamed for the demise of countless olive groves. Farmers were distraught, chaining themselves to their ancient diseased trees to prevent the environmental authorities from removing them, the only way to counter Xylella.

Italy's lost more than 20 million olive trees to Xylella. Part of the end game would be to develop olive varieties resistant to Xylella.

And then there are efforts to attack Xylella itself.

I asked Dr Landa if the gravity of her research project gives her sleepless nights.

So is it a question of when, not if, in terms of the olives in southern Spain?