A manual of rice seed health testing - IRRI books - International Rice ...

CHAPTER 10
Field inspection
J.K. Misra, T.W. Mew, and S.D. Merca
Field inspections—observations of
standing crops—are done at various
stages of plant growth. Field inspections
are carried out by agencies responsible
for certifying or producing
certified seeds, by seed technologists,
and by quarantine personnel.
Officers who inspect fields for
plant quarantine, commonly termed
crop health inspection, may benefit
from employing some methods used
during crop inspection for other purposes.
These methods, as well as the
more traditional quarantine procedures,
are presented below. For seed
certification, field inspectors must
check
crop land requirements;
the source of the crop's seed;
sowing dates, pattern, spacing,
plant ratio, and proper rouging;
purity of the cultivar (e.g., no admixture
with other cultivars);
harvesting methods (to prevent
admixtures);
postharvest operations such as
cleaning, drying, sampling, tagging,
labeling, and sealing; and
other special requirements the
crop may have.
Quarantine officers inspect fields
as pre- or postentry checking for export
and import control to ensure
that no new pathogen is introduced
and to estimate the incidence and
severity of existing diseases. Field
inspections are conducted by experienced
plant pathologists and field
inspectors knowledgeable about
crop diseases in the field. Inspections
start at the seedling stage and are
repeated through maturity to harvesting.
General principles
Some general procedures normally
followed by seed or crop inspectors
are helpful to plant quarantine. The
helpful suggestions include:
Inspect so observations can be
made. from the tops of the plants.
Have the sun at your back or side.
Do not face the sun, as this decreases
visibility.
Inspect the field so as to cover the
maximum possible area. Svensson et
al (1975) prescribed schematic patterns
of walking that are useful for
inspecting large fields (Fig. 10.1).
10.1 Schematic
patterns for walking
a field (after
Svensson et al
1975).