Oranges bug 'hacks insect behaviour'
- July 1, 2015, 9:53 pm
- National News
- 59 Views
HQ City Desk
QUETTA: New research suggests that a bacterium, thought to be the cause of a deadly disease of citrus plants, aids its own spread by altering insect behaviour.
Asian psyllids - the insects behind the spread of citrus greening - were shown to fly further and more frequently after feeding on infected plants.
This increased mobility is thought to enhance the chances of the insect passing the bacterium on.
The research was published in the journal PLOS ONE.
Citrus greening or huanglongbing as it is also known has a dramatic effect on the appearance and health of citrus plants.
The University of Florida's Dr Kirsten Pelz Stelinski, who has been studying the disease, highlighted some of the consequences of the infection during a recent interview with the BBC's Science in Action.
"The leaves start to yellow and [grow] mottled in appearance, the branches begin to die back, the root system dies back and ultimately the tree declines and dies," he said.
"It's a global problem in terms of citrus production throughout the world. Just to give you an example, in Florida alone the industry is a $9bn industry per year.
"There have been millions of jobs lost and hundreds of millions of dollars lost, just because of the impact of the disease. We have 100% of trees infected in many parts of Florida, so it's not an insignificant problem.
"It's only becoming worse as the disease spreads to other citrus growing areas."
Citrus plants affected include oranges, grapefruit and lemons.
Insect transmission:
The disease is thought to be caused by a group of related bacteria and the current study focused on one of the strains implicated: Candidatius Liberibacter asiaticus or CLas for short.
The bacterium replicates inside the citrus plants; in the sap that transports nutrients around the plant.
To get from plant to plant the bacterium has to rely on an insect carrier called the Asian psyllid.
As the name suggests, the psyllid is native to Asia but is thought to have been spread to other parts of the world on shipments of citrus plants - an unforeseen consequence of global trade.
The insect feeds on the citrus plant by inserting a special tube, a proboscis, deep into a leaf and then sucking up some of the nutrient-rich sap.
If it feasts on an infected plant, it too can become infected with the CLas bacterium. When it moves to an uninfected plant to feed, the contagion can spread.
