by Gaylord Mink and George N. Oldfield, originally published 1993
(Acari: Eriophyidae)
This mite is believed to be the sole vector of the cherry mottle leaf pathogen. It has been found in British Columbia, Washington, Oregon, Montana, Nevada and California.
Hosts
Its only known natural host is the wild bitter cherry, Prunus emarginata. Cherry mottle leaf often occurs in sweet cherry orchards in canyon areas where bitter cherry grows wild. The mite has never been found on sweet cherry but, in experiments, mites collected from bitter cherry have transmitted the cherry mottle leaf pathogen directly to sweet cherry and peach. It is possible that it moves from bitter cherry to nearby sweet cherry trees, perhaps carried by the wind, and feeds on the cultivated trees long enough to transmit the cherry mottle leaf pathogen. It is not known how long it can survive on sweet cherries. It does not infest choke cherry.
Life stages
Egg
The egg is white and spherical.
Immatures
The two nymphal stages look similar to the adult but are smaller.
Adult
The adult mite has an elongated body with two pairs of legs at the front.
Life history
The mites live in the buds of bitter cherry and move to new buds as they develop during the growing season. Populations in a single bud may surpass 1,000. Such populations cause buds to swell tremendously and turn red. Infested buds never grow. The mites breed continuously as temperatures permit and overwinter as adults inside the buds.
Monitoring
Because Eriophyes inaequalis is extremely small, the best way to check for infestations is to look for swollen buds.
Biological control
The mite has no known natural enemies. It is protected inside the buds from most potential biological control agents.
Management
Remove bitter cherry trees near the orchard and take out orchard trees that are infected with cherry mottle leaf.