D reyfusia nordmannianae in N orthern and C entral E urope: potential for biological control and comments on its taxonomy

The silver fir woolly adelgid, D reyfusia nordmannianae , is the most severe pest occurring on A bies nordmanniana in C entral and N orthern E urope. The adelgid is particularly damaging to trees in C hristmas tree plantations. D reyfusia nordmannianae is native to the C aucasus region and alien to E urope, where its natural enemy complex is less diverse compared to its area of origin. Mitochondrial and nuclear DNA sequence data from the samples of D . nordmannianae collected in its native range and E urope and from the samples of D reyfusia piceae and D reyfusia prelli collected in E urope and N orth A merica were examined for phylogenetic structure. There was no evidence of differentiation, suggesting that these D reyfusia species have recently diverged or require taxonomic revision. All existing published and unpublished reports on natural enemies of D . nordmannianae in its place of origin were reviewed, with the purpose of selecting agents for classical biological control in E urope. The literature review suggested that the most promising agent was the C hamaemyiidae fly, L eucopis hennigrata . A new survey in D . nordmannianae 's area of origin – T urkey, G eorgia and R ussia – showed that L .  hennigrata was present in all localities. It was particularly abundant in Turkey, where its impact on populations of D . nordmannianae appears to be high. Its use as a biological control agent is discussed, as well as other biological control strategies.