Disease Note

Foliar Ringspot Disease of Thunbergia alata Caused by Broad Bean Wilt Virus. R. Provvidenti, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. H. C. Hoch, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Plant Dis. 69:726. Accepted for publication 9 April 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-726f.

An unreported disease of Thunbergia alata Bojer, an ornamental known as clockvine, occurred in a garden in New York State. Infected plants were stunted and leaves showed prominent ring spots and veinal chlorosis. Broad bean wilt virus (BBWV), the causal agent, was readily transmitted both mechanically and by Myzus persicae Sulz. from T. alata to T. alata and to bean, lettuce, spinach, and Chenopodium quinoa Willd., other hosts of BBWV. All the isolates from T. alata were BBWV serotype I, but serotypes I and II incited the same symptoms on T. alata as those on naturally infected plants. No virus was detected in 134 seedlings grown from seed collected from BBWV-infected T. alata. Other ornamentals in which BBWV has been reported are Ajuga reptans L., Begonia semperflorens Link & Otto, and Cornus florida L.