Effects of hormones on Entomophthora egressa morphogenesis

The morphological effects of a fungal sex hormone, trisporic acid (TA), and a synthetic insect juvenile hormone (JH) on mycelial cultures derived from protoplasts of the fungus Entomophthora egressa were determined. In comparison with the control treatment (no added hormone), only one treatment (JH and TA both added at 40 μg/50 ml) produced all of the control cell types. Under both experimental conditions, normal hypha (without swollen tips), spherical hyphal bodies, irregularly shaped hyphal bodies, and thick-walled spheres were present. This JH plus TA treatment differed from the control in that normal rod-shaped hyphal bodies were also present and the thick-walled structures tended to be variable in shape. Hyphal tip swelling which did not lead to conidium production was common to all treatments in which only JH was added. The results of the addition of various concentrations and combinations of JH and TA with regard to the production of thick-walled cell types and three forms of hyphal bodies are given and discussed.