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Dreyfusia prelli

Prell's adelgid

Description

Dreyfusia prelli is a sap-sucking insect from the family Adelgidae, primarily associated with fir trees (Abies alba, A. cephalonica, A. nordmanniana) and spruce trees (Picea orientalis). Its lifecycle is biennial and involves two hosts: spruce as the primary host and fir as the secondary host. The species has a limited impact on forests compared to other adelgids, yet it can cause significant aesthetic damage and reduce tree vitality in severe infestations.

The insect is 0.2–0.5 mm in size with a bluish-green body. Colonies are found mainly in the crown region of mature trees, where the adelgids feed on young shoots, stems, and branches. Feeding induces the formation of galls measuring 6–30 mm, which appear later in the season (July–August). These galls disrupt nutrient flow and may lead to needle discoloration, deformation, and premature needle drop. Reported in Europe on fir and spruce, Dreyfusia prelli is primarily found in central and southeastern regions of the continent.

Symptom

Galls, 6–30 mm in size, are visible on young shoots or branches, often opening in mid to late summer. Needles near the galls may become discolored, deformed, or drop prematurely.

Tree Species: Fir, Spruce

Part of a plant- attacked: Branch

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: Yes

Present in EU: Yes