ALTERNARIA BLIGHT OF BACHELOR'S BUTTON (GOMPHRENA GLOBOSA L.)

Abstract

1. An Alternaria sp. is reported occurring on Gomphrena globosa L. and G. dispersa Standley. 2. All the ornamental varieties as well as the wild type are susceptible to the disease. 3. The disease is recognized by the sub-circular, yellowish-brown lesions on stems and leaves with a characteristic reddish halo. 4. The pathogene, an Alternaria sp. is described. 5. Conidia from young lesions as well as from an oatmeal culture were used for morphological, physiological and inoculation purposes. 6. The inoculation tests with spore suspensions taken respectively from young lesions as well as from culture proved the pathogenicity of the organism. 7. Conidia placed in water and at room temperature (28 C.) started germination within an interval of 2 to 3 hours. 8. Sporulation was noticed on lesions on the leaves and never on the stems. Dead parts of the plants seem to harbor the pathogene. 9. The disease is more severe during hot, rainy weather.