and sterile tap H2O. All 10 isolates from citrus
were also tested by needle infiltration for
their pathogenicity on three known hosts
of B. andropogonis (4,18): carnation, corn
(Zea mays), and sorghum (Sorghum vulgare),
as described by Cother et al. (10).
Histology of lesions. Isolates 6370 and
6367 were inoculated into newly expanded
leaves of sweet orange and grapefruit, and
samples were collected 2 weeks later at the
inoculation site. Multiple samples of 2 ×
0.5 cm leaf tissues containing both healthy
and inoculated lesion tissue were sectioned
using a razor blade. The sections were
placed in vials containing formalin-acidalcohol
and fixed for 2 h under a 500 hPA
vacuum in a tissue processor. The sections
were dehydrated in a series of alcohol and
Histo-Clear baths and then embedded in
paraffin. The embedded leaf tissue was cut
with a microtome to a thickness of 10 to
15 µm, floated on warm H2O,