Vergara - 1976 - Physiological and morphological adaptability of ri

DISEASE (“KYLE OF RICE BLAST AND CLllVL-KTIC FACTORS 423
previously formed commenced when the relative humidity went beyond 89%.
and the eonidia produced on the previous night were simultaneously counted.
Mature coiliclia were released and new conidia were borne. then released.
DEPOSITION
It is difficult to estimate the number of conidia deposited on the surface of a
host organ. For example, here is an estimation by Yoshino and his co-workcrs
(Kim et all, 1974): (estimated number 0f conidia deposited) = (number of conidia
collected) >< (ratio amended by height) [based on Suzuki's formula (1969b)]
X (coefficient ofdeptisititin) [l/ZOKJ] >< (leaf area/area of sampler).
lNFEC'fl()N AND
COLONIZA'fI(JN
Once the temperature regime rises beyond the lower limit for infection and
colonization in a temperate zone and at high elevation areas in the tropics. the
most determinative climatic factor for infection would be the length of the
viretting period of the host surface. Asai et al, (196?) detected this experimentally
Disoersion
Mu:
lnfecled aortic w.)
I00
50..
I00
0]....
I234
5o._
I .
re u A w
q. w w u: Z
50-
oi l. i. .
l2545hr
B. Deposition time of conidia and percentage of
conidia infected by Ri-wrnlaria 0:11:02 on rice leaves as
wetting proceeds.
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