Untitled - International Rice Research Institute
Untitled - International Rice Research Institute
Untitled - International Rice Research Institute
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Detection frequency (%)<br />
120<br />
100<br />
East Asia<br />
Europe<br />
Latin America<br />
South Asia<br />
Southeast Asia<br />
Sub-Saharan Africa<br />
80<br />
60<br />
40<br />
20<br />
0<br />
Detection level (%)<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
1990 1991 1992 1993 1994 1995 1996 1997<br />
Year<br />
Fig. 10. Detection frequency (a) and level (b) of Bipolaris oryzae from imported untreated seeds, 1990-97.<br />
16.10 µ (PDA); 4–11 septate, 43.47–101.43 µ ×<br />
12.19–16.10 µ (PSA); and 5–11 septate, 59.80–<br />
106.03 µ × 10.12–16.33 µ (MEA).<br />
Colony characters on culture media (Fig. 13)<br />
Colonies on PDA at ART (28–30 °C) grow slowly<br />
and attain a 3.38-cm diam in 5 d. They are azonated<br />
with sinuate margins, hairy at the center, becoming<br />
cottony toward the margin, yellowish gray at the center<br />
and gray toward the margin, and becoming grayish<br />
olive with age. The colony appears azonated and<br />
black on the reverse side of the agar plate. At 21 °C<br />
under alternating 12-h NUV light and 12-h darkness,<br />
colonies grow very slowly and attain a 2.38-cm diam<br />
in 5 d. They are fluffy, azonated with uneven margins,<br />
with olive gray aerial mycelia, becoming dark<br />
olive gray outward. The colony on the reverse side of<br />
the agar plate appears azonated and black. At 28 °C<br />
under alternating 12-h fluorescent light and 12-h<br />
darkness, colonies grow very slowly and attain a<br />
2.53-cm diam in 5 d. They are fluffy with nil to<br />
scanty aerial mycelia, azonated with uneven margins,<br />
and olive black with 3.0-mm light gray advancing<br />
mycelia. The colony appears azonated and black<br />
with light gray margins on the reverse side of the<br />
agar plate.<br />
Colonies on PSA incubated at ART (28–30 °C)<br />
grow moderately fast and attain a 4.48-cm diam in 5<br />
d. They are fluffy, azonated with sinuate margins,<br />
and grayish yellow at the center, becoming dark olive<br />
gray outward. The colony appears azonated and olive<br />
black to black on the reverse side of the agar<br />
19