Seed Testing of Maize and Wheat A Laboratory Guide - Search ...

Detection technique
Freezing blotter method
(See Annex A)
References
Colony on seed grows rapidly with
white aerial mycelium often
becoming tinged with purple,
particularly on the blotting paper.
Mycelium has a powdery
appearance due to the presence
Microconidia, occurring in
abundance, are hyaline, usually
one-celled but occasionally twocelled,
5-12 x 1-3 IJm, oval to ciubshaped
and slightly flattened at
each end.
Abundant uniform microconidia
are formed in long chains that can
readily be observed using the
scotch-tape method (see Annex A)
under the microscope at low
power (x100) .
CMI. 1964. Descriptions of
Pathogenic Fungi and Bacteria
No. 22, Gibberella fujikuroi.
CAB, UK.
of chains of microconidia. Tan to
orange spore masses of irregular
shape and size, are occasionally
present.
Macroconidia occur infrequently,
are hyaline, delicate with thin walls
and vary from curved to almost
straight, 3-7 septate, 25-60 x 2-4
Chlamydospores are never
formed.
Booth, C. 1971. The Genus
Fusarium. CMI, UK.
Note: Infected maize seeds often
have white streaks or are
rotten.
j..Im, and have a foot-shaped
basal cell.
McGee, o..C. 1988. Maize
Diseases: A Reference Source
Chlamydospores are never
present in mycelium or conidia.
for Seed Technologists. APS
Press, USA.
Perithecia, which occur rarely, are
spherical, blue-black, and 250-350
Shurtleff, M.C. 1980. Compendium
j..Im high by 220-300 IJm diameter.
of Corn Diseases. APS Press,
USA.
Asci are oval to club-shaped with
4-8 ascospores.
Ascospores are hyaline, straight,
mostly one-septate, and measure
4-7 x 12-17IJm.
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