My brother lives in southwest France in the department of Lot-et-Garonne, in a house looking across a cultivated valley to the small town of Duras. His garden shelters an enviable variety of wildlife, from black redstarts to western whip-snakes, and he occasionally sends me photos of his more exotic finds.
I have often thought it would be a fascinating spot in which to set up a moth trap and indeed it remains the only place where I have seen that harbinger of doom the Death’s Head Hawkmoth. On one occasion he sent me a photo of a Convolvulus Hawkmoth which he had come across in a nearby vineyard.
His latest photos were also of a moth but not one that was instantly identifiable (photo courtesy of Hugh O’Connor). It bore a superficial resemblance to a hawkmoth and was of equal size to the two just mentioned with a four inch wingspan. To my surprise it was identified in my field guide to British moths as a Surreptitious Palm Borer, a species native to South America where it inhabits open areas with wild palms.
It is thought that it was initially introduced to Europe in the 1990s in palms imported from Argentina which contained eggs or larvae. The eggs are laid on the palm stem and on hatching the larvae bore into the stem and leaves setting up large colonies within the plant. These are not immediately obvious, hence the “surreptitious” part of the name.
Since its introduction it has spread rapidly, attacking species of both native and ornamental palms across southern Europe and is now spreading north. So far my brother has seen just one pair of moths and has decided that treating his two tall palm trees would be prohibitively expensive so is leaving them to it.
In Britain they have been recorded a number of times, emerging from ornamental palms imported from Spain and Italy. It is a classic example of how pest species are introduced along with exotic plants where there is insufficient regulation.
Yorkshire is unlikely to be affected by palm boring moths but a much more important example of the same phenomenon has involved the arrival of the killer fungus responsible for the potential destruction of our native ash trees, probably brought in with imported trees.
It is surely time for greater control over the importation of native trees propagated elsewhere as well as non-native trees and plants which too often bring with them invisible insect pests, killer fungi and pathogens.
By Denis O’Connor