SYNERGISTIC EFFECTS OF A CELLULASE-PRODUCING MICROMONOSPORA-CARBONACEA AND AN ANTIBIOTIC-PRODUCING STREPTOMYCES-VIOLASCENS ON THE SUPPRESSION OF PHYTOPHTHORA-CINNAMOMI ROOT-ROT OF BANKSIA-GRANDIS

Three polyvalent Streptomyces phages were used to isolate four Micromo nospora species (M. carbonacea, M. chalcea, M. purpureochromogenes, an d M. inositola) from mine-site rhizosphere soils in Western Australia, Streptomyces violascens was isolated using selective isolation techni ques from the same soils. The Micromonspora spp. were examined for the ir ability to produce cellulases. Micromonospora carbonacea, M. chalce a, and M. purpureochromogenes, which were found to produce the enzyme, caused lysis of Phytophthora cinnamomi hyphae. Glasshouse trials show ed that the use of the cellulase-producing M. carbonacea isolate, in c onjunction with the antibiotic-producing S. violascens isolate, had a synergistic effect on the suppression of the Phytophthora root rot and in promoting growth of Banksia grandis. The importance of using a num ber of antagonists with different antagonistic abilities to control pl ant pathogenic fungi is discussed.