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

Detection technique
Freezing blotter method
(See Annex A)
References
CMI. 1964. Descriptions of
Pathogenic Fungi and Bacteria
No. 26. Fusarium culmorum.
CAB, UK.
McGee, D.C. 1988. Maize
Diseases: A Reference Source
for Seed Technologists. APS
Press, USA.
Colony on seed has sparse, very
loose mycelium, initially white,
then becoming yellow and finally
brown or red . There is an
abundant production of dull
orange to wh itish pink spore
masses on the seed as well as in
the mycelium . These spore
masses vary in size and are
irregular in shape and slimy in
texture.
Microconidia and perithecia are
absent.
Macroconidia are formed
occasionally on conidiophores
produced laterally on aerial
mycelium but more frequently
they are formed from loosely
clustered conidiophores.
Macroconidia are short, stout,
hyaline, uniformly curved with one
side straight and the other curved,
with a pOinted apical cell and a
distinctive foot cell. The conidia
are generally 3-5 septate, and
measure 26-40 x 4-6 iJm.
Distinguished from F avenaceum,
F graminearum, F crookwelJense,
and F sambucinum by the very
uniform, short, distinctly septate,
th ick-walled, stout macroconidia.
Note: F culmorum is one of the
most stable and uniform
Fusarium sp. although mutants
do occasionally occur and
these generally show a
reduction in pigmentation.
Nath , R., Neergaard, P., and
Mathur, S.B. 1970. Identification
of Fusarium species on seeds
as they occur in blotter test.
Proc. Int. Seed Test. Assoc. 35
(1): 121-144.
Chlamydospores are oval to
spherical, smooth to rough-walled,
single, in chains, or in clumps, and
found at intervals along the
hyphae.
Nelson, P.E., Toussoun, T.A ., and
Marasas, W.F.O. 1983.
Fusarium Species - An
Illustrated Manual for
Identification. The Pennsylvania
State University Press, USA and
London.
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