Resistance is futile – new hope in the fight against insect pests
Media Release, Wednesday 8 June 2005
A PhD student has identified a gene which may help create an early warning system for resistance to insecticides. The discovery was announced at the opening of the University of Melbourne’s Bio21 Institute today.
The pesticide Spinosad is a new generation insecticide – derived from a soil fungus. It is widely used in farming and forestry across the world to protect crops against insects such as fruit flies, caterpillars, leaf miners, thrips, drywood termites and certain beetles.
But resistance is already appearing – the diamondback moth (a global plague of brassicas) became resistant within two years of the release of Spinosad in Hawaii.
“Insects quickly adapt and develop resistance to every insecticide we come up with,” says Mr Trent Perry, a PhD student with the Bio21 Institute and the Centre for Environmental Stress Adaptation Research (CESAR).
“What we need is a way for farmers to detect when resistance is building up so they can modify how they use the insecticide and extend its effectiveness.”
“I have identified a gene that appears to give insects resistance to Spinosad. This is the first step toward monitoring and controlling resistance.”
Most insecticides kill an insect by binding to a receptor in a specific protein that the insect needs for survival. Mr Perry worked with a strain of vinegar fly (Drosophila melanogaster) that was highly resistant to Spinosad and found a mutation in a gene that encodes for a subunit of a particular receptor.
“This receptor is involved in transmitting signals through the nervous system,” says Mr Perry. “We are now going to look at other Spinosad-resistant insects to see if they too have this mutation. That will confirm that this is the gene responsible for resistance developing. Then we can very quickly develop an assay which farmers could use to detect resistance in insects caught on their farm.”
A practical early warning system is an essential tool in developing integrated pest management programs that will allow farmers to keep pests under control.
“We know that insecticides work but for a long time we haven’t known how they work. Finding out what is happening inside the insect - identifying the gene involved - gives us a mode of action,” says Mr Perry. “We can study how resistance develops and then work out a way to detect resistance on the farm.”
“We hope our work will help market gardeners who are using Spinosad on broccoli, cabbage and bok choy; also fruiting vegetables such as tomatoes and eggplants and leafy vegetables such as lettuce, celery and parsley.”
“Understanding how these insecticides really work, and how insects develop resistance, is critical,” says Associate Professor Phil Batterham, Bio21 geneticist and director of CESAR.
“What we are working toward is a whole new generation of insecticides that work specifically against a target pest insect, without ‘friendly fire’ killing beneficial insects,” he says.
And when we identify the unique targets, the chemists based at the Bio21 Institute will be able to help us make molecules that will act as guided missiles – killing the pest insects and nothing else.
Mr Perry is writing up his PhD thesis and has just completed a commerce degree.
“I’m interested in bridging the gap between research and business. That’s where I see the future demand, and that’s what the Bio21 Institute is all about,” says Mr Perry.
Please contact Niall Byrne on 0417 131 977, Sarah Brooker on 0413 332 489, or Elaine Mulcahy 0421 641 506 for more information.
|
|
