Grape rust mite,
Calepitrimerus vitis Nalepa

Grape rust mite is best known from grape-growing areas in Europe, South America, Australia and the Pacific Northwest.  This eriophyid mite is very small and probably won't be seen without magnification. Body length is about 0.1-0.2 mm (1/100 inch).  Adult females overwinter beneath bud scales, under bark, and other protected locations.  They disperse to foliage in the spring.  Feeding by grape rust mite can seriously damage spring growth and buds, resulting in reduced yield.  Feeding on leaf surfaces may cause leaves to turn dark green to black or bronze.  Foliage should be examined under a dissecting microscope to evaluate mites because of their tiny size.  Summer populations may reach very high levels, but may not cause much real damage to the vines; control may be needed the following spring however, to prevent injury to buds and shoots (James 2019).  The presence of some grape mites may actually improve stability of biological control of spider mites by providing additional prey for predatory mites.

Biological control:  Control may be provided by predatory mites.  Growers are encouraged to use pesticides that have low toxicity to these valuable predators (also control agents for spider mites).

Chemical control: In commercial vineyards (OSU 2019), delayed dormant populations may be controlled by sulfur at the woolly bud stage, followed by a spray at bud break (Skinkus 2019).  Spring and early summer populations may be controlled using insecticidal soap, neem oil, Stylet oil, or sulfur.  Late summer - fall populations may be difficult to control because mites may have started their movement to overwintering sites beneath bud scales.


James, D.  2007.  Grape rust mites: New enemies (but ultimately friends) invade Washington vineyards.  Washington State University Viticulture and Enology Program (  Accessed 5 Sep 2019.

OSU. 2019.  Grape - Grape rust mite.  Pacific Northwest Pest Management Handbook. (  Accessed 5 Sep 2019.

Skinkus, P. 2019.  Grape rust mite. Oregon State University (  Accessed  Sep 2019.

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