|Slininger, Patricia - Pat
|OSTROWSKI, RICHARD - UNITED AGRI PRODUCTS
Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/7/1997
Publication Date: N/A
Technical Abstract: Eighteen gram-negative bacteria isolated from suppressive soils have been shown to biologically control dry rot incited by Fusarium sambucinum (teleomorph=Gibberella pulicaris) (Schisler and Slininger, 1994, Plt. Dis. 78:251-255), and several of these have demonstrated amenability to mass production based on favorable growth kinetics and efficacy when cultivated in liquid media. Two strains showing promise in pilot trials were submitted to a variety of liquid cultivation media and conditions in order to cost effectively maximize growth rates and yields. Yields of each strain were increased 5-fold to 16-20 g/L by optimizing dissolved oxygen, carbon and nitrogen supply rates to cultures. When produced in 1.6 L and 80 L fermentors under appropriate growth and formulation conditions, both strains could reduce dry rot by 95% in laboratory bioassays and survive storage with viable population half-lives > 100 days in either -20 deg C or r4 deg C liquid formulations. Both storage stabilities and efficacies displayed by biological control agent preparations varied significantly (P<0.05) with carbon source concentration in the growth medium, age (physiological state) of the culture at harvest, and retention of spent culture broth and metabolites in cell formulations.