Information on smut of pearl millet is quite confused in the
literature. Several apparently unique species have been reported
or implicated in the cause of smut diseases of pearl millet. For
example, Rachie and Majmudar wrote (1980):
The fungus Tolyposporium senegalense Speng. [sic],
T. bullatum Schroet., and Sorosporium bullatum
Schroet. was first reported from Africa (Corbetta
1954); but Mundkur (1940) reported
its occurrence in the region of Poona, India. Hirschorn (1941) suggested the name T. bullatum,
as T. senegalense was only a synonym of the same species.
It also attacks Echinochloa crusgalli in Germany.
Corbetta's (1954) paper is in Italian,
and from what I can understand, he is attempting to clarify the
nomenclature of the smut pathogen of Panicum crus-galli
and P. erectum. I believe that his final conclusion is
that Tolyposporium bullatum, Sphacelotheca destruens, and
Sorosporium panici-miliacei should be named Sorosporium
bullatum. Pearl millet, or an associated smut pathogen of
pearl millet, is not mentioned.
The argument for synonymy of Tolyposporium senegalense
and T. bullatum was made by Hirschorn (1941).
The paper is written in Portuguese (?) and I believe that Hirschorn
promoted lumping these two species based on morphologic similarities.
Cross-inoculation studies were unsuccessful, but he attributed
this to physiological differences. Although similar morphology
may be adequate to include the fungi in the same genus, sporidial
cross-compatibility should probably be examined before concluding
that the fungi are identical, particularly since the two fungi
are reproductively isolated from each other because of host specificity.
Vanky (1977) split several species
out from Tolyposporium into a new genus, Moesziomyces.
After examining the type specimens, it was concluded that T.
penicillariae and T. senegalense were the same species,
M. penicillariae, which differed from M. bullatus.
Mordue (1995) reinforced the observation
that M. penicillariae and M. bullatus are morphologically
similar, but there appear to be biological differences in host
specificity and possibly in germination.
Mundkur (1940) described a fungus
named Ustilago penniseti. This specimen was described from
infection on Pennisetum fasciculatum and has not been demonstrated
to be pathogenic to pearl millet, Pennisetum glaucum. Subsequent
observations of the disease have not been reported.
Likewise, Mundkur (1939) stated
that he considers Tilletia pennisetina and Neovossia
barclayana as synonyms. These type specimens were collected
from Pennisetum alopecuroides and P. orientale,
respectively, and thus cannot be considered to be pathogenic to
pearl millet without completing Koch's postulates. No subsequent
observations of the disease have been reported.
Mundkur's (1939) original report
of Tilletia ajrekari as a pathogen of pearl millet should
also be examined closely. In the description, he stated that a
single infected ovary was found in greenhouse-grown plants. Examination
of other plants in the greenhouse and field failed to identify
any other similar sori. In this case, a new species was described
based on spore characteristics of a single infected ovary. In
a later publication (Mundkur and Thirumalachar
1952) the description is the same; however, here it is implied
that several ovaries were infected. Because of the nonsystemic
infection and other characteristics of the spores, he stated that
it may be a species of Neovossia. "This can be definitely
decided only after the germination of the spores has been obtained."
In this reference he also states "germination unknown"
regarding the spores. This leads me to believe that no inoculations
were ever performed. This possibility, plus the discrepancy between
a single infected sorus as described in the 1939 paper and several
sori in the 1952 reference leads me to question whether this work
is valid or can be reproduced.
Department of Agriculture
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Original posting: June 5, 1999.