VIEW ARTICLE

Survival and Dissemination of Verticillium in Infected Safflower Seed. J. M. Klisiewicz, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Department of Plant Pathology, University of California, Davis 95616; Phytopathology 65:696-698. Accepted for publication 27 January 1975. DOI: 10.1094/Phyto-65-696.

Verticillium dahliae was frequently isolated from seeds harvested from inoculated safflower plants grown in the field and greenhouse. Microsclerotia were found on external and internal tissue of the pericarp, and on the testa of some infected seeds at harvest. Hyaline and torulose mycelia were located in sclerenchyma tissue of the pericarp. Verticillium grew on agar from mycelia in tissue fragments, and from single microsclerotia taken from infected seeds up to 2 years after harvest. Plants were infected by seedborne V. dahliae in autoclaved and nonautoclaved soil. The fungus was isolated from cotyledons, hypocotyls, and occasionally from the roots of 7- to 10-day-old seedlings, and from cotyledons and hypocotyls of germinated embryos. Microsclerotia formed on infected seed pericarps in autoclaved and nonautoclaved soil. Such pericarps proved to be effective inoculum when incorporated in soil. The fungus is not killed by maneb used as a seed treatment for control of seedborne safflower rust.