Mistletoe sucker

The mistletoe sucker (Psylla visci) is a specialized insect species belonging to the order Hemiptera and the family Psyllidae. This pest is strictly associated with the European mistletoe (Viscum album), a hemiparasitic plant that infests various deciduous tree species in gardens, orchards, and forests.

The primary host for this insect is the mistletoe plant itself. By feeding exclusively on mistletoe tissues, the insect maintains a complex ecological relationship with the host plant. While it does not feed on the trees directly, its presence is dictated by the distribution of mistletoe colonies within the tree canopy.

The biology and lifecycle of Psylla visci are closely synchronized with the phenology of the mistletoe. The insects overwinter in the egg stage, typically deposited on the mistletoe stems. As the nymphs emerge in spring, they begin feeding on the sap of young mistletoe leaves, undergoing several developmental stages until they reach the adult form.

The damage caused by the mistletoe sucker includes the deformation, yellowing, and stunted growth of the mistletoe foliage. In some instances, the feeding activity produces honeydew, which promotes the growth of sooty mold. This can weaken the mistletoe colony, potentially reducing its competitive vigor and the rate at which it spreads across the tree host.

Control measures are rarely directed specifically at the mistletoe sucker, as the insect is often considered a minor inhabitant of the host plant. The recommended horticultural practice is the physical removal of the mistletoe plants through pruning. By removing the host plant, the population of Psylla visci is naturally eliminated along with the mistletoe cluster.