Witches’ Broom Disease of Black Raspberry in Oregon. R. H. Converse, Research Plant Pathologist, U.S. Department of Agriculture, Agricultural Research Service, Oregon State University, Corvallis 97331. R. G. Clarke, Formerly Assistant Professor of Entomology, Department of Entomology, Oregon State University; P. W. Oman, Sr., Professor Emeritus, Department of Entomology, Oregon State University; and G. M. Milbrath, Plant Pathologist, Oregon Department of Agriculture, Salem 97310. Plant Dis. 66:949-951. Accepted for publication 7 May 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1982. DOI: 10.1094/PD-66-949.

A lethal disease that caused witches’ broom of Munger black raspberry was found in a commercial planting east of Portland, OR, in 1980 and 1981. The disease appeared to spread rapidly in the field, eventually killing about 75% of the plants. Nearby Willamette red raspberry and wild Rubus spp. in and near the fields of infected Munger appeared to be unaffected. Mycoplasmalike bodies were common in sieve tubes of petioles from infected plants but were absent from symptomless Munger plants. The leafhopper Macropsis fuscula, a vector of Rubus stunt mycoplasma in Europe, was common on wild R. laciniatus in and near the fields of infected Munger. Attempts to transmit black raspberry witches’ broom disease by M. fuscula or by leaf graft or to find additional infected fields were unsuccessful. Antiserum against Spiroplasma citri failed to give positive reactions in enzyme-linked immunosorbent assay serological tests against leaf sap from black raspberry diseased with witches’ broom.

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