Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 31, 1996
Publication Date: N/A
Technical Abstract: Silver scurf has become a major storage disease of potatoes because many strains of the causative fungus, H. solani, are resistant to thiabendazole (TBZ). Biological control may provide an alternative to TBZ. Thirteen potential biological control strains (8 Gram-negative bacteria, 2 Gram-positive bacteria, 2 yeasts and 1 actinomycete) were tested on Red Norland potatoes inoculated with one of 3 strains of H. solani. Several antagonists reduced silver scurf below the inoculated control, with Pseudomonas strain PM1 reducing disease by as much as 21%. Antagonist efficacy varied with the strain of pathogen bioassayed. Coefficients of variation (CV) were determined on data from 12 similar experiments conducted over 2 years. High CV were associated with experiments performed on recently harvested tubers. Sensitivity to bioassay treatments was maximized when tubers had been stored for more than 3 months.