Leaf gal mite

Genus/ Division: Colomerus vitis – grapevine erineum mite, Phyllocoptes vitis – grapevine gall mite

Features

• Pale or reddish raised bumps appear on the upper leaf surface.

• Underneath, soft, fuzzy growth may be present

• Galls can reduce effective leaf area, impairing photosynthesis and weakening vines over time.

Consequences

While aesthetic damage is most visible, heavy infestations may reduce vine vigor and crop yield due to impaired leaf function.

Spread

Mites spread gradually via wind, tools, or vine-to-vine contact and often return each growing season. 

Treatment advices

• Dormant-season oils: Apply horticultural or mineral oils before bud break to smother overwintering mites.

• Targeted miticides: If infestations are severe, use recommended miticides with a silicone surfactant for better adherence.

• Pruning: Remove and destroy heavily galled leaves to reduce mite populations.