Host Spectrum of the Mycoparasite Dimargaris Verticillata

Abstract

SUMMARY Thirty-five fungi classified in the Phycomycetes, Ascomycetes, Deuteromycetes, and Basidiomycetes were used in this study as potential hosts for Dimargaris verticillata. Stimulation of growth of D. verticillata regularly occurred in the presence of each of the 23 Mucorales tested but not in the presence of fungi of other taxonomic groups. Parasitism by D. verticillata, based on normal sporophore formation, occurred on 18 fungi representing 13 genera of Mucorales. Six Mucorales and 11 fungi outside this order were not parasitized under the conditions used. Colony formation of D. verticillata on its hosts was generally limited to the area of parasite inoculation suggesting that the age of the host hyphae is a factor affecting parasitism. Spreading growth of the parasite did occur on three host fungi. No tropic response was observed between D. verticillata and its reference host, Cokeromyces recurvatus. Dimargaris verticillata Benjamin of the Dimargaritaceae is a haustorial biotrophic mycoparasite which was reported by Benjamin (1959) to parasitize Cokeromyces recurvatus Poitras. Benjamin reported that this fungus grew slowly in axenic culture but developed much more rapidly in the presence of a suitable host. Barnett (1970) reported fair growth of D. verticillata on an agar medium. The host ranges of several other haustorial mycoparasites closely related to D. verticillata have been investigated. Ayers (1935) found the host range of Dispira cornuta van Tieghem to be limited to the order Mucorales. Brunk and Barnett (1966) showed that Dispira parvispora Benjamin attacked mainly other Mucorales, but also parasitized the ascomycete, Monascus purpureus Went. These workers also found that Dispira simplex Benjamin did not parasitize any Mucorales investigated