Sporangial responses do not reflect microbial suppression of Phytophthora drechsleri in composted eucalyptus bark mix

Hardy, G.E.St.J. and Sivasithamparam, K. (1991) Sporangial responses do not reflect microbial suppression of Phytophthora drechsleri in composted eucalyptus bark mix. Soil Biology and Biochemistry, 23 (8). pp. 757-765.

Abstract

When morphology and germination behaviour of sporangia produced by Phytophthora drechsleri were examined in the presence of 262 isolates of fungi and 64 isolates of actinomycetes in sterile, irradiated Eucalyptus bark compost (CEB), seventeen response groups could be distinguished. The sporangial responses considered were combinations of direct and indirect germination, inviable maturenormal and deformed-small sporangia. Each sporangial response group was associated with a range of percentage pathogen survival or infectivtty values. There were no obvious relationships between sporangial response groups and pathogen survival or infectivity on Waratah (Telopea speciossima). Few actinomycete or fungal intcractants reduced pathogen survival. However. 72 and 60.9% of the fungal and actinomycete populations, respectively, reduced percentage infectivity to ≤75%. 173 (66%) fungal and 49 (76.5%) actinomycete intcractants caused disease suppression. The results suggest that most of the fungal and actinomycete interactants in the CEB did not suppress the pathogen, but did suppress disease and that P. drechsleri possesses some competitive saprophytic ability. ©

Item Type:	Journal Article
Publisher:	Elsevier BV
Copyright:	© 1991 Published by Elsevier Ltd.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/2902

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