Submitted to: Journal of Industrial Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 1996
Publication Date: N/A
Technical Abstract: Research interest in utilizing specific microorganisms to create a microbial environment suppressive to plant pathogens has increased exponentially in recent years. Despite such intense research interest in biological control, few antagonists have achieved "commercial product" status. A portion of this failure can be attributed to several features common to popularly utilized microbial selection strategies: a) relatively few candidate microorganisms are tested, b) microbes are selected based on the results of an assay that do not replicate field conditions and c) the amenability of microbes to commercial development is excluded as a selection criterium. Developing a biological control product active against Gibberella pulicaris, the primary causal agent of Fusarium dry rot of stored potatoes, is attractive due to the etiology of the pathogen and the favorable conditions for microbial activity that exist in potato storages. Studies will be described in which innumerable microorganisms were screened for biological control activity against G. pulicaris under natural storage conditions via testing communities of microorganisms for suppressive activity. Individual strains were isolated from suppressive microbial communities. For those demonstrating superior efficacy in controlling dry rot in whole potato bioassays, a relative performance index (RPI) was calculated and used to rank strains based both on growth kinetics and efficacy upon cultivation in commercially realistic liquid media. The broader application of the RPI concept to ranking strains for commercial potential based on multiple selection factors that impact the performance of the final product will be discussed.