Paysandisia archon (Burmeister, 1880) parasitized in laboratory by Trichogramma : First success

Palm Borer moth (PBM), Paysandisia archon (Burmeister) (Lepidoptera: Castniidae), was accidentally introduced in Mediterranean area from Argentina and it has been adapted to the climate and the palm species in place. Since 2001, we have observed more damages on the nature (gallery holes, deformation and twisting of palm trunks, drying up of the palms…), and also economic impacts with more than 100 M€ (to control this pest and the Red Palm Weevil). The most PBM attacked palm species in France, Italy and Spain are Chamaeros humilis, Trachycarpus fortune and Phoenix canariensis.

In this context, it is required to find an efficient and practical strategy susceptible to reduce PBM population, respecting the environment and human health. Some alternative methods of control subsist like mechanical control (application of glue) and biological control (fungi, Beauveria bassiana or nematode, Steinernema carpocapsae). However, these alternative methods are expensive and the process is complex. Therefore it is required to find and develop beneficial insects as biological control agents. During the life cycle of PBM, the egg stage is the most accessible, in the crown, and it is before phytophagous stages, so we were looking for an oophagous parasitoid.

As part of the European project PalmProtect (2012-2014) entitled “Strategies to eradication and confinement of palms invasive pests, P. archon and R. ferrugineus”, the objective of this study was to find on egg parasitoid of PBM.

Trichogramma are known as biological control on different crops. Different strains of Trichogramma have been tested on the eggs of PBM according to several modalities (the age of PBM’s eggs, the age of beneficial insect and the ratio between the number of Trichogramma females and the number of PBM’s eggs). Some of them have successfully parasitized P. argoneggs in laboratory. The global efficiency was also taken into account by the number of eggs aborted and parasited.

These preliminary results are very important which brings us to go on this research. Indeed, Trichogramma behaviour studies which have provided good results will allow us to improve their efficiency and to set up release strategy. The choice of the most effective oophagous parasitoid against PBM could be improved.

Furthermore, it would be interesting to explore the efficiency of others oophagous parasitoid species than Trichogramma. The objective focuses firstly on identifying and testing native oophagous parasitoid species from the Mediterranean area and then from Argentina.