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Etiology

Alternaria alternantherae From Alligatorweed Also is Pathogenic on Ornamental Amaranthaceae Species. G. E. Holcomb, Associate Professor, Department of Plant Pathology, Agricultural Experiment Station, Louisiana State University, Baton Rouge, LA 70803; Phytopathology 68:265-266. Accepted for publication 29 July 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-265.

Alternaria alternantherae from alligatorweed was pathogenic on seven ornamental and one weed species in the family Amaranthaceae which were artificially inoculated with suspensions of conidia. Light leafspot infections with moderate defoliation occurred on Amaranthus caudatus, A. retroflexus (a local weed species), and Gomphrena globosa. Moderate infections and defoliation occurred on Alternanthera phylloxeroides (alligatorweed) and A. bettzickiana. Severe infections, defoliation, and occasionally death occurred from inoculations on Celosia argentea var. cristata, C. argentea var. plumosa, and Iresine herbstii.