How to Manage Pests

UC Pest Management Guidelines


Cherry Rugose Mosaic

Pathogen: Prunus necrotic ringspot virus strains

(Reviewed 11/09, updated 11/09)

In this Guideline:


On cherry trees infected by the rugose mosaic strain of the virus, necrotic ringspot symptoms occur early in the season and include yellowing, browning, and shot hole of leaf tissue. (Discolored areas on leaves may turn brown and leaves may drop early in the summer.) Enations develop from the underside of leaves near the midrib. Fruit may be deformed and may ripen later than normal. Additional symptoms include distorted growth, death of twigs, buds, or young foliage, and stunting of trees.


The virus is spread in pollen and seed as well as via budding and grafting with infected wood. Thrips feeding is suspected to spread the virus from infected pollen into the tree; otherwise virus from infected pollen remains confined to the seed.


To manage Prunus necrotic ringspot virus, use virus-free budding material and rootstock in nurseries and plant certified nursery stock in production orchards. Immediately remove trees that develop symptoms to prevent spread to other trees in the orchard. This is especially critical in blocks that are being used for scion wood. Mow or disc cover crops and weeds before stone fruits bloom in order to reduce the buildup of thrips populations on flowering weeds, as they may otherwise contribute to the spread of the virus.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440


J. E. Adaskaveg, Plant Pathology, UC Riverside
J. L. Caprile, UC Cooperative Extension, Contra Costa County

Acknowledgment for contributions to Diseases:
W. D. Gubler, Plant Pathology, UC Davis
B. L. Teviotdale, Kearney Agricultural Center, Parlier

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