Marchalina hellenica is a sap-feeding insect. It produces large amounts of honeydew on which sooty moulds develop. Marchalina hellenica can infest a range of different pine species, but has only been detected on Pinus radiata, Pinus pinea and Pinus halepensis. It prefers bark crevices and moves around the tree according to the life stage. Infestations are observed on trunks, branches and exposed roots, with egg laying common on branches where smaller nymphs have access to sap. It is covered by abundant white waxy secretions. Large populations cause branch dieback, gradual desiccation, eventually followed by tree death. In Australia, Marchalina hellenica has been causing defoliation of the 2nd, 3rd and 4th year needles on each tree and appears to be a factor in the death of one Pinus radiata tree.
This is the first report of Marchalina hellenica in Australia. Preliminary evidence indicates that the pest is restricted in its distribution.