Complete guide for comprehensive control of Paysandisia archon in palm trees

La paysandisia archon It is a large butterfly, with a wingspan of up to 10 cm, capable of causing Severe damage in different species of palm trees.

While the red palm weevil is often the main cause of concern for the health of palm trees, the butterfly known as the palm borer (paysandisia archon) represents a comparable threat or even higher due to its difficult detection and efficient destruction capacity. paysandisia archon It is native to South America (northern Argentina, Uruguay, southern Brazil, Paraguay), where it is naturally controlled by its predators. However, in areas such as the Iberian Peninsula and especially in areas of the Valencian Community, Its introduction has caused havoc when that breaks ecological balance.

Characteristics and biological cycle of Paysandisia archon

La paysandisia archon It goes through several distinct stages: egg, larva, pupa, and adult. The egg measures between 4 and 6 mm, is fusiform, whitish/pink, and is usually deposited in the crown of the palm tree, hidden among the fibers. Upon hatching, the larvae are born rosy and after the first moult they acquire a ivory white colorThey go through 7 to 9 larval stages, during which they penetrate the interior of the trunk, excavating long galleries up to one meter long.

La duration of the larval cycle varies: caterpillars born at the beginning of the season (spring-summer) can complete their development in a single year, while those born in autumn usually produce caterpillars with a biannual cycle. When the larva reaches maturity, it produces a palm fiber cocoon and silk where it transforms into a pupa. After about 30 days the adult butterfly emerges, which is easily identifiable by its wingspan (78-112 mm), greenish-brown forewings and orange hindwings with white bands and spots, and clubbed antennae. Females are larger and have a long telescopic ovipositor. Adults are daytime and its activity is concentrated from May to October.

this insect attacks both native species such as Chamaerops humilis and ornamental species (Phoenix canariensis, Phoenix dactylifera, Trachycarpus fortunei, Washingtonia spp., Livistona spp. and many others). The plague has a special preference towards the apical areas and the tender buds of the palm tree.

Identification of palm trees affected by Paysandisia archon

• Holes and galleries in newly opened leaves: The larvae bore into the palms while they are still folded inside the trunk, so that when the leaves unfold they show holes, often in the shape of a fan.
• Accumulation of fiber debris and excrement: A sticky paste composed of crushed fibers and excrement is observed near the base of the crown and the exit holes of the larval galleries.
• Remains of chrysalides or exit holes: Frequently visible on the trunk, sometimes with the exuvia anchored, an unequivocal sign of the metamorphosis cycle.
• Weakening and drooping of the trunk: Damage to vascular tissues results in decreased sap flow, loss of vigor, and even color changes in certain areas.
• Death of the apical budIf the larva destroys the only growth tip, the palm tree cannot regenerate leaves and ends up dying.

Susceptible palm trees and extent of the problem

Paysandisia archon affects a very wide range of speciesAmong the most common:

• Chamaerops humilis (Mediterranean palm heart)
• Phoenix canariensis (Canary Island date palm)
• Phoenix dactylifera (date palm)
• Trachycarpus fortunei
• Washingtonia will spin y W. robust
• Livistona chinensis, Livistona australis, Livistona decipiens, livistona saree
• butia yatay, butia capitata
• Trithrinax campestris
• Syagrus romanzoffiana
• brahea armata, Brahea edulis
• Sabal minor, saw palmetto, Mexican Sabal
• Phoenix reclines, roebellini phoenix, phoenix sylvestris

Historic palm groves, urban areas, public gardens, and botanical collections are particularly threatened. This pest has an impact on both the for all Economic commitment , the cultural, with vigilance and prompt action at sensitive points being critical.

Control and treatment methods

Effective control of Paysandisia archon requires a combination of preventive, biological and chemical strategies. Currently, authorized chemical treatments have limitations and their use is subject to constantly evolving regulations, so it is essential to consult the applicable regulations before any action.

• Prevention: The key to preventing the spread is regular inspection, especially when acquiring new specimens or transplanting. It is essential to block adult flight (entangling or immobilization) between May and October, when peak reproductive activity occurs.
• Selective pruning: Removing affected leaves reduces aesthetic damage, but does not eradicate the pest as the caterpillars are inside the trunk.
• Mechanical control and manual removal: Manually extract the larvae following the galleries. This operation must be done with extreme care and knowledge.
• Chemical phytosanitary treatmentsThere are a small number of approved active ingredients, mainly formulations containing phosmet or thiamethoxam. These should be applied to the crown or through endotherapy (injection into the trunk). This should always be done by certified personnel and in accordance with the recommended doses and frequencies.
• Biologic control: The use of entomopathogenic nematodes as Steinernema carpocapsae It is presented as an environmentally friendly alternative for controlling larval stages. Entomopathogenic fungi and specific traps for capturing adults are also being studied.
• Destruction of dead or unrecoverable specimensTo stop the spread, any palm tree with irreversible damage must be cut down and destroyed under technical criteria.

Regulations and recommended actions

Phytosanitary authorities keep up-to-date the decrees and regulations that classify the pest as unusable and make it mandatory to control and eradicate it in areas of high ecological, economic, or cultural value. Applying any phytosanitary treatment requires a professional applicator's license.

The presence of paysandisia archon It is one of the most serious threats to palm trees in our environment. Its slow but persistent damage, the difficulty of eradication, and the limited available phytosanitary arsenal require us to stay informed and act preventively. Through regular monitoring, the application of authorized treatments, and professional intervention, its impact can be minimized.