Cause A phytoplasma that is transmitted only by the blunt-nosed leafhopper. This disease was first detected in Wisconsin in the 1920's and subsequently brought into New Jersey and Massachusetts. The disease was noted in the 2001 edition of "Cranberry Production PNW 274" with symptoms observed in both Oregon and Washington. The disease is not spreading actively and is of only minor importance because the insect vector is not found in Western North America. However, after decades of its absence in commercial beds in New Jersey and Massachusetts, it has been found in several beds in the mid 2010's. If vines are secured from either of those two states, they should be inspected for the disease and the vector before being imported into the PNW. The new hybrid 'Crimson Queen' appears to be especially susceptible to the disease.
Symptoms The lobes of the calyx become enlarged at bloom, and petals are short and streaked with deep pink, red, or green. Flowers usually are sterile (do not produce berries). Branching is stimulated, resulting in a witches' broom. Foliage on infected plants might redden prematurely and fall. Diseased vines grow few if any runners and tend to die out over time. The symptoms of the disease are often confused with other blossom problems.
Cultural control
- Remove infected plants and dead vines when noticed.
Reference Polashock, J.J., Caruso, F.L., Averill, A.L., and Schilder, A.C. 2017. Compendium of Blueberry, Cranberry and Lingonberry Diseases and Pests. 2nd Edition. St. Paul, MN: APS Press.