Geographical Distribution and Long-Term Monitoring of Physokermes hellenicus (Hemiptera: Coccomorpha: Coccidae) on Abies spp. (Pinales: Pinaceae) in Greece

SIMPLE SUMMARY: The scale Physokermes hellenicus (Kozár & Gounari) (Hemiptera: Coccidae) benefits apiculture because it supplies bees with honeydew in Greek fir forests. However, there is limited literature available on its geographical distribution and level of infestation. Thus, in the current study, we investigated these issues in several mountains of Greece. Additionally, P. hellenicus infestation in combination with its natural enemies and honeydew production was monitored for a long period in three (Menalon, Parnis and Tymfristos) highland bee foraging areas. Overall, there was an extensive geographical distribution of the scale, which was negatively correlated with the latitude of the surveyed areas. A decline in P. hellenicus infestation in Menalon resulted in a reduction in honeydew production by this scale. ABSTRACT: The scale Physokermes hellenicus (Kozár & Gounari) (Hemiptera: Coccidae) has been recently included in the Greek entomofauna as a beneficial honeydew species. However, there are no adequate data about its geographical distribution and degree of infestation. Therefore, a study was conducted to examine these parameters in fifteen mountains of Greece. Furthermore, the monitoring of P. hellenicus infestation was carried out over a six-year period with regard to natural enemies and honeydew presence at three mountains (i.e., Menalon, Parnis and Tymfristos) that are traditional honeybee foraging areas. An extensive geographical distribution of the scale was negatively correlated with the latitude. Over the period of the study, P. hellenicus infestation exhibited a decreasing trend in the three mountains, which was more obvious at Menalon. The abundance of natural enemies of P. hellenicus, their effectiveness on honeydew excretion and the fecundity of P. hellenicus are discussed. The reduction in the honey produced at the Menalon mountain (a protected designation of origin product) could be attributed to the reduced presence of P. hellenicus in the fir forest. Among the other identified arthropods, Dreyfusia nordmannianae Eckstein (Hemiptera: Adelgidae) is reported for the first time infesting Abies cephalonica (Pinales: Pinaceae) in Greece. Furthermore, this species is reported for the first time as a co-parasite with P. hellenicus on A. cephalonica in Greece. Since D. nordmannianae is a serious pest, additional research is needed to determine its status in Greek fir forest ecosystems.