Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2004
Publication Date: 2/1/2005
Citation: Plant Disease 89:206 Interpretive Summary: Hoary cress is a target of biological control efforts in the U.S. Diseased and dying hoary cress plants were found near Tunis, Tunisia in 2002, and the fungus Cercospora bizzozeriana was determined to cause the disease. In the laboratory, it was found that this fungus readily caused disease and significant damage on hoary cress, and that this particular fungus has potential as a biological control agent of hoary cress.
Technical Abstract: In the summer of 2002, dying L. draba subsp. draba plants were found around Tunis, Tunisia. Plants had grayish-white leaf spots on most of the leaves. In most cases the leaf spots coalesced, and the leaves wilted and died. The fungus isolated from the leaf spots conformed to the description of Cercospora bizzozeriana. Stems and leaves of 12 rosettes were spray inoculated with an aqueous suspension of conidia and covered with plastic bags in a greenhouse. Symptoms were observed after nine days. No symptoms were observed on non-inoculated plants. C. bizzozeriana was re-isolated from the leaves of all symptomatic plants. This isolate of C. bizzozeriana is a destructive pathogen on L. draba subsp. draba making it a good candidate for mycoherbicide development. To our knowledge, this is the first report of C. bizzozeriana on L. draba subsp. draba in Tunisia.