Two months on and 99 beekeeping sites infected but where did varroa mite come from?

Since the varroa mite was found at the Port of Newcastle two months ago, backyard gardeners to big business have kept a close eye on daily developments.

Ninety-nine infected bee hive sites later, the threat of the deadly bee parasite remains for Australia’s $70-million-a-year honey industry, and the industries that rely on pollination.

To date, it has been found at New South Wales properties from the Central Coast, through the Hunter and up to the Coffs Coast and inland at Narrabri.

So, what have we learned and where to from here?

How did varroa mite get to Australia?

Millions of bees are being destroyed as a result. But how did varroa mite get here?

“It’s a little bit too early to say,” said Department of Primary Industries (DPI) acting chief plant protection officer, Chris Anderson.

Varroa mite was first detected on June 22 at two sentinel hives at the Port of Newcastle, so it could have come in via ship.

The sentinel hives are designed to detect pests and diseases at their earliest entry and are checked every six to eight weeks.

Given the COVID impacts on shipping, and subsequent delays at the port, the NSW DPI says it is difficult to tell how long the mite could have been lingering.

“One of [the COVID challenges] is the large backlog of container ships sitting off the coast of places like Newcastle,” Dr Anderson said.

Bee movements have been halted since June.(ABC Landline: Leah White)

Dr Anderson says there are currently a lot of different theories.

“If you look at the numbers of mites on the IPs [infected premises] around Newcastle, there certainly is a particular area, which is around Williamtown, on both sides of Williamtown, where there are higher numbers of mites than there are anywhere else, which would indicate that that’s the epicentre,” he said.

“That doesn’t indicate that someone has done anything illegal. It may simply be an accidental import on cargo or it may be a swarm that’s come off a ship off the coast of Newcastle and has flown into that area.”

Where in the world did it come from?

Again, we are not sure yet but more testing is underway.

Australia had been one of the few countries around the world to have kept the varroa mite out, and there is a long list of where these mites could have come from — Asia, Europe, North America, South America or New Zealand.

We know from early testing that the varroa mite that NSW is dealing with does not have any issues with chemical resistance to miticides used overseas.

“Which is good news,” Dr Anderson said.

“That means that the chemical applications that we would be using to control varroa in Australia would be effective at this point in time.

“But we still don’t have that answer yet on the actual source country, the country of origin.”

NSW Apiarists’ Association president Steve Fuller says early testing shows positive results.(ABC Rural: Kim Honan)

NSW Apiarists Association head Steve Fuller says that gives some industry some confidence and miticide strips have been bulk ordered.

“It’s caught us a little bit unawares because we didn’t have a great big stockpile because it has a [short] shelf life,” he said.

“I think we had 80,000 come in a couple of weeks ago and we’ve got another container coming in.”

Mr Fuller said most beekeepers would be facing a $50-$80 a year price to have the strips in their hives — if varroa cannot be eradicated.

“The bees actually brush against the strips and that coats them with a miticide, then the mite comes into contact with it and the mite dies,” he said.

There are conflicting views regarding whether the mite can still be contained.(ABC Rural: Kim Honan)

Can varroa mite be eradicated?

With nearly 100 infected hives, has the horse bolted?

Ben Oldroyd, emeritus professor of biology from the University of Sydney, praised the efforts from industry and government but warned the prospect of eradication was unlikely.

“The first point that we must remember is it’s never been eradicated in any other country in the world,” he said.

“The second point is that we’re probably better prepared than any other country in the world.

“It does seem to me that there are a large number of infected premises and the likelihood of keeping it under control from overseas experience would seem to be very low.”