New Zealand wipes out Pieris brassicae

[wollastoni]

www.newscientist.com/article/2114573-new-zealand-is-the-first-country-to-wipe-out-invasive-butterfly/

The kind of articles that make me nervous, I can understand that the NZgovernment want to try and stop the arrival of Pieris brassicae but :

. "Killing was done by using insecticide spray, and care was taken not to destroy any native butterfly species. "  --> SURE ! Your native butterflies will love those insecticides !

. " Wasps that attack P. brassicae were also released in 2015 to bolster the efforts" --> GREAT ! And we are 100% sure you have ckecked that these wasps won't eat any of your local insects.... yes, we are sure...

. "Since the NZ$3 million campaign finished in December 2014, careful searches have not found any more great white butterflies. “We’re confident we can declare them eradicated,” says Primary Industries Minister Nathan Guy." 

--> SURE ... 2 seasons to take a conclusion like this one... true that your campaign has costed NZ$3 M  but come on... be serious

. “If none have been seen for two years despite intensive searches, that is a reasonable claim,” says Myron Zalucki at the University of Queensland, Australia." --> SURE, SURE, SURE. Have this Myron already looked for butterflies to say this ?

And the best :

"Similarly, another pest butterfly in New Zealand – the small white butterfly (Pieris rapae) – is believed to be too firmly established to eliminate."

So these guys has spend 3 Million NZ$ to spray insecticides, introduce non-native predators to eliminate a non-native butterfly which eats plants... that are already treated and will remain treated to fight against another butterfly....

+ Pieris brassicae living in Asia, I am sure he will come back every 2 year by boat... but it will be the occasion to put more insecticide sprays and parasitic wasps in NZ.

[nomihoudai]

Interesting story. I cannot share your concerns.

I checked it and the two wasps species are "non native", but they exist in large numbers in NZ since the 1930s. They are Cotesia glomerata and Pteromalus puparum. www.doc.govt.nz/Documents/conservation/threats-and-impacts/animal-pests/great-white-butterfly/great-white-butterfly-annual-report-13-14.pdf

The butterfly was first spotted in 2010 in a well defined space. It was good to intervene quickly when NZ has over 50 species of Brassicae at risk. Reintroduction is a risk, but I think not such a high risk as the butterfly wasn't introduced until very recently.

[jshuey]

I also do not share your concerns. This is potentially large threat to both agriculture and native mustards on an island where native species and ecosystems are facing severe threats from invasive species. New Zealand has a well-known aggressive approach to early detection / eradication efforts for such species during the early stages of establishment. It is simply a lot easier to wipe out such species before they expand across the island and start to have unforeseen ecological impacts. By then, it’s too late.

New Zealand’s efforts are world-class in this regard. So much so, that when we (TNC), started looking for an aquatic invasive species biologist to focus on the U.S. Great Lakes – guess what country we ended up hiring from?

John