Preliminary Assessment of Colletotrichum capsici as a Potential Mycoherbicide for Control of Pitted Morningglory. D. K. Cartwright, Former Graduate Assistant, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. G. E. Templeton, Distinguished Professor, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Plant Dis. 76:995-998. Accepted for publication 20 May 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0995.

An isolate of the indigenous fungus Colletotrichum capsici, pathogenic on pitted morningglory (Ipomoea lacunosa), was isolated in the summer of 1989 and evaluated in laboratory and growth chamber tests as a potential mycoherbicide. The fungus grew well at 20, 25, and 30 C on potato-dextrose agar containing streptomycin. Conidia germinated at 15, 20, 25, 30, and 35 C, with optimal germination at 25 and 30 C. Disease symptoms developed in 2–3 days on pitted morningglory seedlings at the cotyledonary stage when seedlings were inoculated with 1 × 10⁶ conidia per milliliter and incubated in a dew chamber for 24 hr at 30 C. All seedlings were killed within 5–7 days after inoculation. Two sequential 12-hr dew periods resulted in 86% mortality. The only other crop or weed species tested that was susceptible was sharppod morningglory (I. trichocarpa var. trichocarpa), which was as susceptible as pitted morningglory to the pathogen. Results from controlled environmental studies support field testing and further development of this isolate of C. capsici as a potential commercial mycoherbicide.