Double whammy: virulent “new” pest threatens Algarve palms

Paysandisia archon is a stunning moth that originates from the South American countries of Argentina, Brazil, Paraguay and Uruguay. It was “mistakenly” introduced to Europe in 1999 in imported ornamental palms. At its larval stage it burrows into trees, ultimately causing their death.

Last week, an attack by Paysandisia - whose larvae are markedly longer and whiter than those of RPW - was identified in a private garden in Praia da Luz, near Lagos. This was the first known incidence of the insect which was identified as having reached Valencia, in Spain, in 2010 – after ravages in France and Italy.

To make matters worse, the affected palms - Howea forsteriana (or Kentia palms) - are NOT a species previously considered to be at risk from the insect. Equally worrying, if not puzzling, was the fact that they were in a garden that included a number of Paysandisia’s previously documented preferred hosts. In other words, the list of potential host species is growing.

“This is yet another example of man’s harmful effect on the environment”, lamented environmentalist Tony Lambe, who has spent years researching effective ways to control the Red Palm Weevil. ”In its habitat, Paysandisia is kept at bay by native predators. They could be a type of bird, or small rodent – or even a fungus - but here in Europe those natural controls do not exist,” he explained.

Lambe has been a fierce critic of the authorities - both national and European – which dragged their feet for so many years before imposing import controls on trees blighted by RPW, that the pest managed to spread like wildfire.

There is now almost no country with palms in the world that hasn’t lost trees to RPW.

“In light of the incompetence displayed by the local authorities - which did not even impose a quarantine on the Algarve when it was the only place in the country with the Palm Weevil - I now really fear for all the botanical gardens we have in Lisbon and Sintra,” he told us “We stand to lose a huge part of our botanical heritage”.

So far, Paysandisia’s preferred hosts include the beleaguered Phoenix canariensis (an RPW favourite), Chamaerops humulis – a native Algarvian palm and Trithrinax campestris, Washingtonia, and Syagrus palms – all popular varieties sold in garden centres throughout the region.