VIEW ARTICLE

Herbaceous Host Plants of Western X-Disease Agent. D. D. Jensen, Professor, Division of Entomology, University of California, Berkeley 94720; Phytopathology 61:1465-1470. Accepted for publication 13 July 1971. DOI: 10.1094/Phyto-61-1465.

Western X-disease (WX) is an important disorder of stone fruits, apparently caused by mycoplasma. The agent of WX was shown experimentally to cause disease symptoms in the following herbaceous plants: periwinkle, chrysanthemum, China aster, radish, turnip, cauliflower, filaree, strawberry, carrot, coriander, celery, and Gomphrena globosa. Parsley has also been reported to be susceptible to infection. All transmissions of the WX agent were accomplished by means of the leafhopper vector, Colladonus montanus. WX agent-free leafhoppers recovered the WX agent from all symptom-bearing plants that were tested, and transmitted it to celery indicator plants. The incubation period of WX symptom development in susceptible hosts was ca. 4-6 weeks. Susceptibility to WX infection varied among the herbaceous hosts; carrot was the most resistant, and several species, such as celery and turnip, were very susceptible. Periwinkle plants, after developing symptoms of WX, remained susceptible to the aster yellows agent and produced symptoms distinctive of aster yellows disease.