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New Bacterial Disease of Lobelia erinus Cultivar Richardii Caused by Xanthomonas campestris. G. Poschenrieder, Bayerische Landesanstalt für Bodenkultur und Pflanzenbau, Voettingerstr, 38, D-8050 Freising. E. Lohweg, W. W. P. Gerlach, and J. D. Janse. Staatliche Versuchsanstalt für Gartenbau Weihenstephan, Institut für Botanik und Pflanzenschutz, D-8050 Freising 12, West Germany; and Plantenziektenkundige Dienst, Geertjesweg 15, NL-6700 HC Wageningen, Netherlands. Plant Dis. 74:252. Accepted for publication 5 December 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0252C.

A leaf blight and dieback of Lobelia erinus L. 'Richardii' was noticed in 1988 in a commercial nursery near Munich, West Germany (1). The disease later appeared in other glasshouse units io Germany and in 1989 was found in a greenhouse in the Netherlands containing plants obtained from Great Britain. Losses within individual houses ranged from 3O to 100%. Symptoms began as a water-soaking, followed by chlorosis of leaf bases and adjacent areas on the stems. These areas became necrotic, leading to death of acropetal portions of the stem. Watcr-sosking and chlorosis initiated at leaf tips were followed by necrosis that developed interveinally. Occasionally, droplets of bacterial ooze were seen. Gradually the plants died, especially those that were watered overhead. Isolations from diseased tissue as well as symptomlrss plantd conistently yielded only a yellow bacterium. Based on results of standard physiological and biochemical tests, as well as fatty acid analysis, the baclerium was identified as a new pathovar of Xanthomonas campestris (Pammel) Dowson. Spray inoculations of the: causal bacterium (1 X 108 cfu/ml) onto healthy seedlings reproduced the symptoms secn on naturally infected plants. The suspect pathogen was reisolated from tbe inoculated plants, which died within 4 wk. The bacterium was pathogenic to artificially inoculated L fulgens L. 'Queen Victoria' plants. but tbe only symptom was severe stunting. This is the first report of a disease in Lobelia causcd by a pathovar of X. campestris.

Reference: (1) G. Poschenrieder et a1. Gb + Gw 88:2204, 1988.