American leafminer moth Coptodisca lucifluella has been invading Italian walnut orchards since 2010. Interestingly, the moth lives on pecan trees in the United States, but invaded a new host plant in Europe: the walnut tree.

 

Coptodisca lucifluella occurs in eastern North America from Texas north to New York. It feeds as larva on several species of wild hickory and commonly on pecan in orchards, e.g. in Georgia, where it is a minor pest. In North America the moth has never been found on walnut.

 

In Italy the species is widespread from the Veneto in the north to the Basilicata region in the south. The leafminer can develop 3-4 generations per year and is abundant in most of the investigated orchards, except those in higher altitudes. Almost all leaves appear to be infected, but overall the density is still low.