Ci après un texte d’un site anglophone domicilié en Espagne. Intéressant surtout par le constat que dans ce pays les gens se battent contre ce ravageur tout aussi dangereux que le CRP.
Chez nous rien de tel, un classement qui n’engendre aucune action opérationnelle spéciale. Le refus des pouvoirs publics d’inclure ce ravageur dans le nouvel arrêté de lutte contre le CRP. Nous comptons évoquer ce grave problème lors d’une prochaine réunion avec SRAL PACA. Par ailleurs, une question sera prochainement posée à l’Assemblée nationale.
"First of all let’s meet this insect. The scientific name is Paysandisia archon, it belongs to the order Lepidoptera and the Castniidae family. It is originally from South America, specifically from northern Argentina, Uruguay, southern Brazil and Paraguay.
A new threat to palm trees : paysandisia , a pest that is causing virtually the same damage as the red weevil. This insect, also commonly known as a palm borer, can quickly kill the plant if proper treatment is not done on time.
It was discovered in 1880 by the Argentine nationalized German entomologist Karl Hermann Konrad Burmeister , who gave it the name of one of the main Uruguayan cities, Paysandú, which borders Argentina. In this area lives the Paysandisia archon, feeding on the native palm trees of Rio de la Plata. In its South American natural habitat it is considered a rather sparse butterfly, effectively controlled by its natural predators that have evolved with it over millions of years. The first observations in Europe occurred in the 90s in Catalonia. Some fertilized females managed to cross the Pyrenees and others went to areas of Valencia, Alicante and the Balearic Islands, where the main pests are concentrated.
This insect is also known as the "palm borer", or "palm hole driller" and is a moth or butterfly shaped lepidoptera.
It develops very similar to the red weevil in terms of its evolution as a larva, but it takes more time to pierce the palm, especially in the periphery and at the base.
The adults appear from May and after a few days the female makes the laying at the base of the crown of the palm tree. The flight of this insect ends in October and with it the laying period.
After the hatching of the eggs, the caterpillar is introduced inside the palm tree digging galleries.
As the larva is laid, the caterpillar will have an annual or biannual cycle. In the annual cycle, the caterpillar comes from a spring setting, appearing as an adult the following spring.If, on the other hand, the larva was born at the end of summer or autumn, the caterpillar does not complete its development before winter, so it needs another year to appear as an adult.
When the caterpillar reaches maturity, it produces a cocoon with chewed fibers of the palm itself, which is then lined with silk and transformed into a pupa or nymph. The caterpillar makes an exit hole in the trunk of the palm tree, where the adult will leave. About 30 days later it emerges as an adult butterfly.
The adult of this species is a diurnal butterfly that can reach 10 cm.
Regulations on the plague in the Valencian Community
- Order of May 26, 2003, where the official existence of the plague is declared and its fight and eradication is described as public utility.
- Decree 131/2003, of July 11, for the integral phytosanitary protection of palm trees of relevance
Historical, economic, social and cultural community.
What damage does Paysandisia produce to the palm ?
The damages produced by Paysandisia in palm trees are several. The caterpillars bore the palms when they are still folded inside the trunk and when the palms come out and open they have holes. On the other hand we will know that the palm is affected when we observe the remains of hardened fiber in the exit holes of the galleries they make.
Its main damage is that produced by the sweeping larvae by perforating the trunk and building galleries that will prevent the flow of the sap and with it the loss of vigor of the palm tree, so, frequently, some inclination of the trunk can be observed in the affected area as well as a color change in that area.
These are the species in which plague attacks have been detected :
Chamaerops humilis (native of the Mediterranean)
It constitutes an important threat to large areas of palm heart in the Peninsula, as well as to the palm trees of the Canary Islands and specifically to areas and places of great cultural and economic importance such as the palm groves of Elche, Orihuela or Alicante .
The Paysandisia attacks in the same way as the Picudo but with longer cycles and has a greater incidence when generating foci with more affected specimens than the beetle.
Treatments against Paysandisia archon
To control this pest, the most important thing is prevention, by reviewing and controlling palm trees that come from other countries. On the other hand, if the pest is already present in palm trees , they must be immobilized or meshed from May to October to avoid the flight of adults and infect others.
Pruning the affected leaves does not eliminate the pest, only the damage ; you have to fight the caterpillar that is inside the palm tree, with several insecticide applications per year. "