THERE are high hopes the new strain of calcivirus being released this week will dramatically reduce rabbit numbers, which have grown significantly in recent years.
PIRSA Natural Resource Management biosecurity manager John Virtue said the new strain was being released at 600 sites across the country, including 45 across SA.
Dr Virtue said PIRSA was working with NRM and Landcare groups across SA to ensure the successful release of the RHDV1 K5 virus.
“One of the key things with this release is that it will be concentrated in high rainfall areas,” he said.
“This strain is predicted to work really well in high rainfall areas, which was a deficiency in the original release of calcivirus.
“Another important aspect we’re looking at is younger rabbits. With the present strain, younger rabbits can survive and build up an immunity.”
Dr Virtue said there would be intensive monitoring at the 600 sites.
“We’ve looked at what the rabbit population was before the bait went out and we’ll go back a month later, when we will hopefully see a significant decline in numbers,” he said.
“Rabbit numbers have been slowly increasing in recent years. There was a big drop when the virus was first released in 1995, but there has been a build in resistance since that time.
“This is the first field testing of the new strain in Australia, but in the laboratory it has come out as one of the most effective strains tested.”
Dr Virtue said it was important farmers did not rely solely on the new strain for rabbit control.
“Integrated control is still important, rabbit warren ripping and poison baiting are still fundamental,” he said.
“This new strain gives the opportunity for a big drop in numbers, but if farmers can go back with other tools, it gives them a good chance to finish the job off.”
Biosecurity SA research officer David Peacock said pre-feeding rabbits at sites where the strain was being trialled was an important part of the process.
“Rabbits don’t like new things, so it’s important to get them used to different food before we go out with the virus,” he said.
Livestock SA president Geoff Power described the pests as “silent assassins”, because of their impact on farming operations.
“They have a huge effect on biodiversity,” he said.
“We’ve noticed the difference in the country since we’ve reduced rabbit numbers (in arid regions). Plants that weren’t there before are back.”
Mr Power hoped the new strain would be effective in high rainfall areas and complement existing rabbit control measures, such as warren ripping.
