Rowan gall mite

Systematic position: Eriophyes loewi belongs to the class Arachnida, order Trombidiformes, and family Eriophyidae (gall mites). These are microscopic, worm-like mites known for their highly specialized parasitic lifestyle, which involves inducing abnormal plant growth.

Host range: This pest primarily affects the rowan tree or mountain ash (Sorbus aucuparia). It is commonly found on both wild populations of the tree and specimens planted for landscaping and ornamental purposes in parks and residential gardens.

Biology and life cycle: The life cycle is strictly synchronized with the phenology of the host plant. Adult mated females overwinter in protected areas, typically under bud scales. As soon as the buds begin to burst in spring, the mites migrate to the developing foliage, where their feeding activity induces the formation of galls. The mites complete several generations within these protective structures throughout the growing season.

Damage and impact: The presence of Eriophyes loewi is identified by the formation of numerous tiny galls on the upper leaf surface. These galls often start as light green or yellow patches and eventually turn brown or reddish. Heavy infestations cause significant leaf distortion and premature senescence, potentially leading to widespread defoliation and a decline in the tree's overall vigor.

• Prune and destroy heavily infested branches during the dormant season.
• Apply specific acaricides at the early bud burst stage to target emerging mites.
• Use sulfur-based sprays to suppress mite populations during the summer.
• Ensure proper tree maintenance to promote resilience against parasitic infestations.