Ash aphid

The ash aphid (Prociphilus bumeliae) is an insect species belonging to the order Hemiptera and the family Aphididae. It is recognized as a significant pest of ash trees, causing structural and physiological damage to the foliage during the spring and summer months.

The host range is primarily focused on the genus Fraxinus (ash trees). The aphids congregate on the undersides of leaves and on young succulent shoots, where they feed by extracting sap, leading to stunted growth and a general decline in the tree's vitality.

The life cycle involves a complex migration pattern. After overwintering as eggs, the nymphs emerge in spring to feed on new growth. The population includes wingless and winged generations, with the latter often migrating to intermediate hosts to continue their life cycle before returning to the primary host in autumn to lay eggs.

Damage is characterized by intense curling and twisting of leaves, often forming tight, gall-like structures that provide protection for the aphid colonies. The secretion of honeydew often leads to the development of sooty mold, which coats the leaves and further inhibits the tree's ability to undergo photosynthesis effectively.

Effective management strategies include both cultural and chemical approaches. Cultural practices involve pruning and destroying heavily infested branches. Chemical control should rely on systemic insecticides applied early in the season, before the leaves have curled, as this allows the chemical to reach the aphid populations effectively inside the leaf structures.