Antibiotic culture filtrates produced by
Bacillus
(CA5) and
Streptomyces
spp. were tested for
translocation and persistence when applied on snap beans inoculated with rust (
Uromyces appendiculatus
) in
greenhouse pot experiments. The antibiotics were applied on the first trifoliate leaves and translocation was assessed
as the number of rust pustules on non-treated leaflets or trifoliates while persistence was assessed as the number of
rust pustules on rust infected plants at different times after antibiotic treatment. The treatments were replicated three
times, each replicate consisting of a pot containing three plants. Antibiotics from both
Bacillus and
Streptomyces
were found to have up to 100% trans-lamina and leaflet-to-leaflet translocation but no significant trifoliate-totrifoliate
translocation. The antibiotic culture filtrates also retained significant rust control for up to 10 days after
application on the bean plant. However, no significant rust control was found on the plants after 16 days of treatment.
The study indicated that the antibiotics produced by antagonistic
Bacillus and
Streptomyces species possess systemic
activity that can persist within the plant for over one week. These metabolites are potential bean rust control products
that could be incorporated in integrated disease management programs