Impact of sap-sucking insect pests (Blastopsylla occidentalis Taylor and Glycaspis brimblecombei Moore, Hemiptera: Psyllidae) on unifloral eucalyptus honey

Eucalyptus species are important worldwide as melliferous plants, as a source of nectar and pollen, and contribute to the production of large quantities of honey, especially in summer when E. Camaldulensis Dhnh., the most common eucalyptus species in the Mediterranean area, flowers. Its honey yield potential exceeds 200 kg/ha, sometimes accounting for more than 50% of total apiary production. In Italy, eucalyptus plantations cover at least 50,000 hectares, corresponding to a potential production of 10,000 tons of honey per year. Since 2000 several invasive eucalyptus pests have spread and settled in the Mediterranean. Of these, psyllids Blastopsylla occidentalis Taylor and Glycaspis brimblecombei Moore have become major threats to eucalyptus plantations. The main objective of this study was to verify the impact of sap-sucking insects unifloral eucalyptus honey production and quality in Northern Sardinia (Italy). Our results show that a pronounced decrease in honey production occurred after 2011, with no production at all in 2012 and 2013, partial recovery in 2014-2016 and a further increase in 2017 and 2018. Moreover, the incidence of honeydew produced by psyllids has led to modifications in the chemical-physical characteristics and pollen spectrum of unifloral eucalyptus honey.