AU: Grower voices concerns tests for watermelon virus are not nationally consistent
The NT Department of Primary Industry has placed quarantine zones around farms in Katherine and Darwin and is currently checking other crops that are susceptible to the virus.
However, Mick Jakob, manager of Red Dirt Melons in Katherine's Venn District, says he's concerned testing in other states are inconsistent with methods in the Top End. Mr Jakob says he was told by the New South Wales Department of Primary Industries that test strips, which can be used in the field to check for the presence of CGMMV, were very accurate.
"In the first information we got about the CGMMV, these strips were recommended [for] on-site detection," he said. "We used them extensively on our farm, we checked every crop before we picked and all our crops came back negative. I rang the DPI in New South Wales, asked how accurate these test strips are and I got told they are very accurate."
Then, at a biosecurity grower meeting in Katherine with the NT Department of Primary Industry, he was told the test strips are 'basically useless.'
"That's why the DPI NT did further testing, at the end the final result came through DNA testing of the virus, where the final positive result came from," Mr Jakob said.
Dr Satendra Kumar, the director of Plant Biosecurity at the New South Wales Department of Primary Industries, says test strips can be used by farmers as a quick, preliminary method to check for the virus.
"The test strips are generally a good diagnostic tool on ground situations, where if a grower wants to very quickly use some sap of the plant to ascertain whether it spells positive or negative," Dr Kumar said. "A lot of times these strips do work but other times [they] may not."
However Dr Kumar says laboratory testing is needed for the final confirmation of the presence of the CGMMV.
"We have to do all tests according to the accepted protocol, currently that is the VCR and sequence analysis," he said.
The New South Wales watermelon season is still in its early stages, so the NSW DPI says it is too early to conduct high level surveillance.
"We have been keeping a look-out at the Sydney markets, and if we do see any symptoms, or suspect fruit, then we send that to our labs for analysis," Dr Kumar said. "[Test strips] are not an acceptable test for diagnostics, especially when we're dealing with an exotic plant pest, such as Cucumber Green Mottle Mosaic Virus. It is the same protocol that the Northern Territory is using, they are using PCR sequencing analysis, and once that's concerned then the virus is confirmed on the property.
"There has been a national protocol developed for surveillance, and we will ensure we take appropriate steps in implementing that surveillance program, collection of samples and sending those samples to the Elizabeth McArthur Institute laboratory for testing."
Source: abc.net.au