Crop protection - Enlisting the aid of DNA 'spies'

By Emma Leonard

Microsatellites – an invasion of privacy or ground-breaking science? The insect pest Helicoverpa armigera would regard it as the former, but graingrowers should be heralding this new ‘spy’ technology as the latter.

Helicoverpa is a major crop pest, but understanding its migration has been hazy, until now. World-leading research by Dr Kirsten Scott from the University of Queensland and a network of collaborators across Australia, with funding from the Cotton and Grain RDCs, is providing fundamental information on the insects’ movements.

The microsatellites used by Dr Scott are small pieces of DNA which change structure rapidly and dramatically between generations.

The portion of DNA being used varies in length between different Helicoverpa populations. This means that as populations migrate and interbreed a new length of DNA is found.

“A visual analogy would be when colours are mixed. If white is added to red, pink is produced, add more red and a new colour dark pink appears,” says Dr Scott. “By monitoring these changes we are able to establish the migration patterns of populations of Helicoverpa.”

Migration patterns have varied between years. In the 2002-03 drought, the bugs predominately stayed in the region from which they emerged. In better years, 2001-02, they were seen to move in small steps throughout eastern Australia.

“From this data we have established that H. armigera populations generally originate from cropping areas rather than migrate in single large events from central Australia, as previously thought,” says Dr Scott. “Distance migrated depends on the season; so together these two facts emphasise that control at a farm level is the key to minimising population growth.”

The project is considered to be the world’s most intensive pest research using genetic monitoring tools.

For more information:
Dr Kirsten Scott, 07 3365 2455,

GRDC RESEARCH CODE UQ00029, program 3

Region North