Sorghum Diseases in India

espectively. Elevation above mean sea level is
between 100 and 150 m.
Three institutions—Kasetsart University located
in Bangkok, Khon, Kaen University located
in the Northeast, and Thailand's Department
of Agriculture (with field-crop stations all
over the country)—are now conducting research
in sorghum improvement.
Farmers are using the cultivars Early and
Late Hegari, KU 439, U-thong I (or DA 80), and
the recently released Department of Agriculture's
Supanburi 60, an open-pollinated release
with red pigment. Hybrid varieties are sold by
private sectors, mostly to the higher income
farmers or big farms. The demands for hybrids
will continue as long as the higher price of sorghum
grain prevails.
Disease has the potential of being one of the
factors limiting sorghum production in Thailand
(Table 2). Grain diseases, such as grain mold
and ergot, can effect quality and yield. Leaf diseases
are considered less important than grain
disease in Thailand mostly because they occur
after seed-set and the grain has already filled.
Table 2. Sorghum diseases found in Thailand.
Disease
pre-
Disease Pathogen valence 1
Grain mold Curvularia lunata 1
Fusarium spp 2
Colletotrichum
graminicola
1
C. gloeosporoides 2
Phoma sp 2
Ergot Sphacelia sorghi 1
Rust Puccinia purpurea 2
Gray
leaf spot
Cercospora sorghi 1
Anthracnose C graminicola 2
C. gloeosporoides 2
Zonate leaf Gloeocercospora 3
spot sorghi
Charcoal rot Macrophomina
phaseolina
3
Leaf blight Exerohilum turcicum 2
Tar spot Phyllachora sorghi 3
1. Prevalence: 3 >2 >1
42
Many sorghum diseases have been recorded in
Thailand (Pupipat 1980). These diseases are
still occurring, and spread occasionally if the
weather favors pathogen development. However,
severe yield losses seldom occur, perhaps
due to the cropping system; farmers grow sorghum
following maize, and maize downy mildew
does not infect sorghum in Thailand. Sorghum
is also sown as a mixed crop with cotton,
beans, and sesame; these species are not alternate
hosts to sorghum pathogens
Research on Sorghum Diseases
Grain mold
Grain mold on sorghum has been studied by
Kasetsart University and the Plant Pathology
and Microbiology Division in Thailand's Department
of Agriculture. Disease resistance was
tested at Suwan Farm. Diseased grains were
isolated and the causal fungi found to be from
13 genera. The most prevalent are Curvularia
lunata, Fusarium spp, Colletotrichum graminicola,
C. gloeosporoides, and Phoma sp. Of these, only
Curvularia lunata and Fusarium spp appeared in
Pupipat's listing (1980), which reported Aspergillus
spp as well.
Aspergillus is a strange mold. Mutation was
induced (using gamma radiation at 35 and 40
Kr), but disease resistance has not yet been
found. The project continues.
Rust
The screening technique for selecting resistance
to rust has been to inoculate at 20-22 °C and 95%
RH, including a trace amount of polysorbate 20
in the spore suspension. Infection on sorghum
seedlings takes place uniformly within 10 days.
Urediospores were viable 30 days after collection
from the field.
Ergot
Sorghum ergot, first found in Thailand in 1983
on Sudax (Boon-Long 1983), was identified as
Sphacelk sorghi (Sudax is a commercial pasture
crop developed from crosses between selected
male-sterile sorghum and sudan grasses). In