3. Results
3.1. Bacterial growth
The bacterial colonies on TTC and YDA agar and individual cells
showed the typical R. solanacearum morphology after 48e72 h of
incubation at 28 C. Mucoid colonies grown in the TTC medium
appeared to be white with pink-reddish centers. The mucoid
colonies grown on the YDA medium were creamy-white, opaque
and fluid. After inoculation in tobacco leaves, both colony types
were virulent.
All R. solanacearum isolates caused wilt symptoms and plant
death in the inoculation tests. The first sign of wilt appeared 15 days
after inoculation and plant death occurred about 40 days after
inoculation.