Control basal rot of cutting of Chrysanthemum and other ornamentals
1950
Tompkins, C.M., University of California, Berkeley (EUA). Department of Plant Pathology | Middleton, J.T., University of California, Berkeley (EUA). Department of Plant Pathology
Basal rot of chrysanthemum cuttings is of general occurrence in cloth house propagating benches in San Mateo and Santa Clara counties, California. Symptoms of the disease consist of brownish-black, water-soaked lesions at or near the base of the cuttings. Infection spreads upward in the stems and downward into the roots, discoloring all tissues. Wilting may occur in advanced stages of the disease. Stem tissues become soft and shrunken, and the cuttings collapse. Symtptoms on cuttings of other ornamental plants included in these studies are similar. Low air and soil temperatures and excessive soil moisture apparently predispose chrysanthemum cuttings to infection. The causal organism of the disease affecting chrysanthemum has been identified as Pythium ultimum Trow, and its pathogenicity has been proved. Pythium ultimum was also isolated from the infected cuttings of 19 genera in 18 families of ornamental plants, but no infection tests were undertaken. Basal rot of cuttings of chrysanthemum and other ornamental plants studied can be controlled by dusting their basal ends with a mixture of Ferbam and Celite 505. Cuttings may be inserted into either clean or used sand in propagating benches.
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