New rapid diagnostic pest test to aid Western Australia's grains industry

 

Western Australian researchers have developed a rapid DNA-based diagnostic test to aid the State in the early detection of one of the world’s most unwanted grains pest.
 

Department of Primary Industries and Regional Development research officer Oonagh Byrne said researchers at South Perth modified a previously published  overseas method and road-tested it as a high-throughput screening test for the Khapra beetle.
 

“Khapra beetle, which is not found in Australia, is one of the most serious pests of stored grain products,” Dr Byrne said.
 

“This molecular test offers a quick ‘first pass’ screen for suspect specimens – assisting our valuable grains industry in proving absence of this pest to future-proof market access, and add to our tool kit in the event of a pest incursion.”
 

Dr Byrne said the polymerase chain reaction (PCR) test took a few hours and needed only a small fragment of an insect to produce enough DNA for testing and follow-up sequencing.
 

“The PCR test can be used on all life-stages of the beetle, and provides a quick diagnostic response, where standard methods can take days or weeks,” she said.
 

Dr Byrne said it had been ‘road tested’ against Khapra beetle samples from around the world, along with thousands of native Australian insect relatives which could be mistaken for Khapra beetle.
 

“Australia is home to many benign relatives of the Khapra beetle and we wanted to know whether this PCR test would be able to tell them apart,” she said. 
 

“Several years’ worth of targeted trapping around grain silos across Australia have fed into this research – providing specimens for DNA testing, sequencing, and morphological verification, resulting in a valuable legacy resource.
 

“At last count, around 15,000 individual insects have been collected and accounted for in the national trapping program.
 

“Having PCR-screened such an extensive collection of insects, with no confirmed positives, means this simple PCR test can help reassure industry that WA isn’t harbouring a concerning exotic pest.”
 

The test will be used at the department’s diagnostic laboratory in South Perth.
 

Dr Byrne said the molecular diagnostic protocol for Khapra beetle would be submitted to the national plant health committee for consideration as a national diagnostics protocol for use throughout Australia.
 

The DNA sequences of Australian native insects will be submitted to an internationally recognised genetic resource website.
 

This research was funded by WA Government’s Boosting Biosecurity Defences project.