Fire, fire, burning blight

Do you like apples and pears? So does fireblight. Do you enjoy climbing trees? So does fireblight.

Fire, Fire, burning blight,
In the forests of the night;
What data or criteria,
Could frame thy cruel bacteria?

The poem may be cute, but the contagious disease is not. Do you like apples and pears? So does fireblight. Do you enjoy climbing trees? So does fireblight.

Unlike you, however, fireblight does not understand the concept of environmental sustainability, and its appetite is entirely without limits.

Fireblight is a disease affecting apples, pears, and some other members of the Rosaceae plant family. A blighted tree is easily recognised: blossoms, shoots, young fruit, and other tissues shrivel and blacken within a few weeks of infection.

The disease’s causal pathogen Erwinia amylovora is believed to have originated in North America. Since the 1950s, however, the bacteria has oozed onto a global stage, having been imported to Europe via the transatlantic fruit trade.

The disease has since spread to most of the rest of the world and poses a serious concern to apple and pear producers. Under optimal conditions of hot, wet weather, fireblight can destroy whole orchards of crops in a single season.

Australia is fortunate to presently be fireblight-free. Nevertheless, protecting the nation’s apple and pear orchards – and industries – remains a complex challenge. Trade opportunities, for example, must continually be contrasted with biosecurity considerations. Indeed, the biosecurity threat posed by fireblight is so severe it caused the Australian Government to ban New Zealand apple imports for 90 years; despite the ban being abolished in 2013, trade protocol remains extremely strict.

“A fireblight outbreak in Australia could have nasty consequences,” says Associate Professor John Rathjen from the ANU Research School of Biology. “All of us from producers to consumers must remain vigilant against this unwanted threat to our apple and pear orchards.”

Caution in this area remains wise: there currently exist no effective spray-on antibiotics in Australia to neutralise the effects of fireblight, making strict avoidance of contaminated fruit the only option for protecting Australian crops.

Prevention is indeed better than a cure, particularly when the search for a cure has yet to reach actualisation. Still, there are many more overgrown paths to explore in the plant pathology field before we can deem this particular research area fruitless.

The Fireblight, by Rosalind Moran (with the help of William Blake)

Fire, Fire, burning blight,
In the forests of the night;
What data or criteria,
Could frame thy cruel bacteria?

And why with distant shoot and apple
Did thine sickness choose to grapple?
On what wind did thou ensnare
The health and beauty of the pear?

And what malice, and what art?
Doth make thee tear young fruit apart?
And doth thine pathogen love grief
When oozing forth on wilted leaf?

When the stars threw down their spears
(And NZ imports stopped for years)
Did fireblight smile its work to see?
In browning leaves on blighted tree?

Fire, Fire, burning blight,
In the forests of the night;
What data or criteria,
Could frame thy cruel bacteria?