Disease Note.

First Report of Colletotrichum coccodes on Velvetleaf. A. R. Gotlieb, University of Vermont, Burlington 05405. A. K. Watson, and C. Poirier. McGill University, Ste-Anne-de-Bellevue, Quebec H9X 1C0. Plant Dis. 71:281. Accepted for publication 1 December 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0281A.

In Vermont, Colletotrichum coccodes (Wallr.) Hughes (DAOMI83088) was isolated from velvetleaf (Abutilon theophrasti Medic.) leaves showing a slight foliage blight. Pathogenicity was proved by completing Koch's postulates. Symptoms began as discrete chlorotic spots, followed by water-soaking, formation of circular buff-colored lesions that coalesced, desiccation, and finally foliage drop. Conidia (109 / m2) sprayed on velvetleaf in the field at the two- to three-leaf stage caused severe defoliation within 2 wk and plant death at 3 wk. Stem infection occurred under severe disease conditions. The biomass of velvetleaf was reduced by 89%, compared with controls. This isolate of C. coccodes is highly specific for velvetleaf and has excellent potential as a mycoherbicide for the control of velvetleaf.