“Unleash the insects!” Ambitious new plan to attack the scourge of Ozzie wattle

Known in Portugal as “acácia” – and stunning when in flower – it is in fact considered one of the most invasive plants on the mainland, one that is not simply threatening natural biodiversity, but actually altering soil conditions and the dynamics of coastal dunes.

Trying to keep the rampant spread of acácia-de-espigas (Mimosa, or wattle by various names) at bay has involved huge costs this far, and led pretty much nowhere which is why Coimbra investigators have now come up with an innovative “totally natural” plan.

There is a tiny wasp from Australia (the acácia’s native country) that can stop the plant’s proliferation in its tracks.

The plan is to unleash this minuscule creature in and around Coimbra this autumn.

As Público writes, this is the first time an insect has been deliberately introduced into Portugal to “cull” an invasive plant species – but will it sting Coimbra’s inhabitants along the way?

Strangely, this little detail has been left uncovered in the various articles written this week, which concentrate instead on the 12 years it has taken to devise the plan.

“If it was badly done, it could lead to very bad results”, Hélia Marchante of the environmental department of Coimbra’s agricultural school has warned.

The principal risks could be other plants, which is why research has taken so long to narrow down the best wasp for the job.

This particular critter – scientific name: Trichilogaster acaciaelongifoliae – destroys the acácia’s reproductive cycle by laying its eggs at the point where flowers would bloom. The eggs hatch into larvae that then chomp away, giving the plant no chance to flower (and therefore reproduce) ever again.

Now, after dotting all the ifs and buts – and skirting round the issue of a populace driven mad by yet another stinging insect – Coimbra’s plan is ready for take-off, with wasps due to arrive in 15-kilo pods from South Africa very soon.

Areas to be used for the project stretch from Figueira da Foz to São Jacinto, Marchante told reporters – with coastal areas, for now, being left alone.

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