Assay for antagonism to Xoo races
Antimicrobial activity of actinomycete strains was carried out by the
agar-piece method (φ 6 mm) on Wakimoto medium. A total of 90 actinomycete strains were screened for their antogonism to races of Xoo. Pure cultures of actinomycete isolates were inoculated on YS medium at room temperature (25 to 30°C) for 7 to 14 days. After adequate growth of the isolates, the pieces of agar (φ 6 mm) that contained actively-growing actinomycete isolates were cut and placed onto the test plates culturing races of Xoo. The plates were incubated at 28 ± 1°C for 2 to 4 days and the inhibitory effect of the actinomycete isolates on Xoo growth was evaluated by measuring inhibition zones (cm)