Bad Bugs: Ranking the creepy crawlies threatening our economy

Don Rowe takes a deep dive into the disgusting to rank the diseases and bugs currently plaguing our shores, threatening our agriculture and tourism industries.

Just as our clean green image is threatened by the various turds, both bovine and backpacker, flooding into our waterways, so too is our biosecurity consistently in danger of bugs big and small. Bacteria, insects, fungi – all manner of potential ecoterrorists wait ready to swoop upon our forests, farms and even bloody old oysters.

On Monday this week MPI announced the launch of their ‘future-focused’ biosecurity intelligence squad, one of four new business units being set up including Fisheries New Zealand, Forestry New Zealand and New Zealand Food Safety, all of which will launch in May. The squad will look to modernise technology and increase the use of analysts to glean what they can from offshore information regarding potential threats – before they can arrive at the border.

Which is all well and good, but the fact remains we face voracious internal threats already. I have done the googling, and helpfully ranked the greatest threats to agriculture to save us from yet another working group. Call me Captain Planet.

1. Myrtle Rust

Myrtle rust is not just the only bug on this list to directly screw up my weekend, shutting down the tracks summiting Mt Karioi just south of Raglan and preventing a lovely hike, it’s also hugely damaging to pohutukawa, manuka and rata trees – posing a dire threat to some of our most iconic and beautiful species.  

First sighted in New Zealand in May, 2017, the fungal disease has spread over much of the country, affecting plants everywhere from Golden Bay to Northland. While the original plan of containment and eradication was a failure, MPI has shifted to a science-based response, hoping to understand the resistance of native species and the extent of the problem.

“We now have well over 540 infected sites across the North Island and now the top of the South,” say MPI’s myrtle rust response spokesperson Dr Catherine Duthie. “Because of the windborne, pernicious nature of the disease, we have to anticipate that there are likely to be many more infected sites beyond these.”

How did it get here? The answer, my friend, may be blowing in the wind; DOC says Myrtle rust is likely to be carried by wind to New Zealand from Australia, New Caledonia or Raoul Island – but we don’t really know where it came from, or even whether its the same type as that from Australia or New Caledonia.

2. Kauri dieback

It would be almost fitting in a timeline as bleak and dumb as our own that Tāne Mahuta, Lord of the Forest, could be brought down by some dickhead’s dirty boots, but that’s the state of things.

Kauri dieback is an incurable and rabid pathogen which starves the tree from the inside out. This evil shit can literally sense the roots of the kauri tree, and swims towards them with a “tail-like flagella”. It can survive in the soil for years, thrives in the rain, and can bring down a thousand year old tree in a few years. Kauri have little to no natural resistance to dieback, and it’s thought that this nasty bit of goods has been lurking in the soil plotting a takeover for decades.

Te Kawerau ā Maki placed a rāhui on the Waitakere Ranges last December, but while it was supported by Māori throughout Aotearoa, much of the Waitakere community, the Tree Council, Forest & Bird, the Independent Māori Statutory Board (IMSB), Te Tira Whakamātaki The Māori Biosecurity Network, and – eventually – Auckland Council, kauri dieback continues to spread throughout our forests because some people just don’t reckon it applies to them, eh.

While it technically may be just another form of mould, so too was the organism that killed almost a million Irish during the Great Potato Famine.

3. Pea weevil

First discovered in New Zealand in July, 2016, the pea weevil single handedly shut down Wairarapa’s booming pea farming industry when the Ministry for Primary Industries banned growing the crop in the district. While reports in December last year indicated MPI believed they were on the verge of total eradication, last month the growing ban was extended for another 12 months.

“After the 12 months we can then review whether a continued total ban, partial restrictions or other measures will be the best option going forward, based on what the trap crops show us,” Wairarapa Federated Farmers Arable chairperson Karen Williams said at the time.

And where did this dastardly weevil wend its way from? The likeliest suspect, pea farmers say, is imported seed from the US.

Eradication methods include ‘trap-crops’, whereby small pea crops are sewn for the purpose of attracting mature weevils which are then sweep-netted and the bugs destroyed. While it’s no Judas Goat, I remain a big fan of any plan which pulls a fast one on pests of any description.

4. Mycoplasma Bovis

2017 was a terrible year for farmers. Not only did Labour form a coalition government helmed by ‘pretty communist’ Jacinda Ardern, but cows nationwide were shocked to learn that Mycoplasma bovis had been found on farms in New Zealand.

The bacterial disease, which causes untreatable mastitis, ear infections and late term abortions in cattle is also the primary causative agent of bovine tuberculosis. MPI estimates Mycoplasma bovis could cost the country as much as $400 million.

Last month MPI announced a commercial diagnostic tool was under development in a partnership between commercial laboratories, industry representatives and MPI, but that will be of little relief to the 20,000 cattle marked for euthanisation – may they rest in peace.

And how did this revolting disease infect our bountiful shores? Imports are again suspected, with foreign bull sperm and even illegal drugs in investigators’ sights.

 

5. Bonamia ostreae

Perhaps the only bug on this list that is near unequivocally good, doing a number on what is easily the worst and least palatable shellfish on offer, B. ostreae has been found in many of the oyster farms at the bottom of the country. Near undetectable ahead of mass oyster deaths, the parasite poses a great risk to the incredibly valuable Bluff oyster crops, but no risk whatsoever to consumers.

Bonamia ostreae is a small, single cell organism, just two to five thousandths of a millimetre in size, and was first discovered in the Marlborough Sounds in 2015. While New Zealand is yet to feel the effects of widespread contamination, the European oyster industry was devastated by B. ostreae, and many farmers were forced to shift to alternative species such as the Pacific oyster. Again, this revolting bug which can cause lesions and fatal, “intense infections”, probably got here via infected oysters as that’s how it’s mainly spread. Do we need to build a wall?

While there is no evidence of B. ostreae in the wild oyster beds in Foveaux Strait, MPI says concurrent infections of B. ostreae and B. exitiosa, and the currently low population size and densities of oysters in the fishery, could be “catastrophic”.

Good thing I can’t stand oysters.

Brown Marmorated Stink Bug (Getty Images)

6. Stink bug

It’s not even here yet and people are already freaking out. This guy, the brown marmorated stink bug, has been busted hitching a ride on a couple of boats bound for NZ. So far, the folks at MPI have managed to keep it at bay, but if this little blighter set foot here it could cost us as much as $4 billion in exports by 2038.

Why are these bugs so stink? They’re hard to see, hard to kill, travel far and they breed fast. Horticulture New Zealand chief executive Mike Chapman told media it’s not only a danger to agriculture. “The infestation in the United States is just awful, there are videos online of people sweeping it out of their home and their broom is just covered with the little b…..s.”


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