Details on Unaspis yanonensis in Côte d'Azur (FR)
In France, Unaspis yanonensis (EPPO A2 quarantine pest) was introduced in Côte d'Azur (coastal strip of Provence-Alpes-Côte d'Azur region) in 1964, and rapidly became an important pest of citrus. In Côte d'Azur, 20 ha of citrus orchards are still present, but are submitted to high pressure from urban development. In addition, many citrus trees can be found in private gardens. They generally constitute reservoirs for citrus pests, and in particular for U. yanonensis. Despite compulsory treatments (chemical treatments) against this scale, U. yanonensis continues to cause serious problems. In the 1980s, several attempts of biological control were made, essentially with Aphytis yanonensis and to a lesser extent with Coccobius fulvus. In 1997, a survey was carried out to identify the species of natural enemies present. The following species were found: Encarsia citrina, Aphytis melinus, but no trace of Aphytis yanonensis was found. The authors pointed out that Aphytis yanonensis was found to be very effective when it was released in the 1980s, but to ensure its efficacy regular releases should be made.
Sources
Kreiter, P.; Marro, J.P.; Dijoux, L.; Tourniaire, R. (1998) La cochenille japonaise des agrumes, Unaspis yanonensis - Sur la côte d'Azur le problème n'est toujours pas résolu.
Phytoma - La défense des végétaux no. 508, 32-33.