Sorghum Diseases in India

Ekukole (1985) found a few infections of
maize streak virus on pearl millet in the Samaru
area.
Striga hermonthica
The root parasite Striga hermonthica is a major
constraint to millet production and is the most
costly weed species in western African cereals
production (Laycock 1986). S. hermonthica in the
sorghum and millet fields of subsistence farmers
is said to be the most important pest-control
problem in western Africa (Ogborn 1984). Striga
hermonthica can substantially reduce yield in
nearly all millet-growing areas of the western
African Sahel, Yield losses up to 65% are recorded
in Burkina Faso (Ramaiah 1985). At the
subsistence level, the Striga problem will in­
crease with growing population and consequent
cultivation of millet on unsuitable land.
In general, Striga infestations in farmers'
fields are more severe in areas with low fertility.
Pearl millet varieties of western African origin
tested for Striga reaction in pots and in a sick
plot in Niger in 1987 did not show resistance
(Table 4). The susceptible control, Sadore local,
had the highest Striga infestation, but the best
yield as well. This might indicate that local varieties
are tolerant to Striga hermonthica if the infestation
pressure is not too high. In general,
progress in identification of resistance sources is
slow, and future research strategies to address
the Striga problem will require integration of efforts
of agronomists, physiologists, breeders,
soil scientists, and plant pathologists. A regional
approach, coordinated and clearly focused
within the western African region, is essential.
Table 4. Reaction of entries from the ICRISAT Pearl Millet Zone A Trial (IMZAT) to Striga hermonthica
in Striga-infested pots and in a Striga-sick plot, ISC, Sadore, Niger, rainy season 1987.
Entry Origin
Mean 1 Striga
plants pot 1
at 66 DAS 2
Survival 3 (%)
at 107 DAS
Mean 1 Striga 4
plants pot -1
(9 M 2 )
Grain yield
(t ha- 1 )
ICMV IS 85 333 ISC, Niger 29.7 (2.80) 100 3.8 (1.29) 0.78
CT2 INRAN, Niger 34.2 (2.68) 83 13.8 (2.65) 0.76
IKMC 1 INERA/ICRISAT,
Burkina Faso
36.8 (3.45) 100 7.5 (1.99) 0.57
SE 2124 IAR, Nigeria 39.5 (3.50) 67 4.5 (1.48) 0.24
IKMV 8201 INERA/ICRISAT,
Burkina Faso
58.2 (3.67) 83 6.0 (1.65) 0.28
SE 361 IAR, Nigeria 78.0 (4.10) 83 3.5 (0.97) 0.22
Control (Sadore local) 52.3 (3.90) 67 55.3 (3.78) 1.14
SE (±0.11) (±0.08) ±0.04
Trial mean (15 entries) 0.55
CV (%) (32) (38) 40
1. Entries ranked by mean Striga plants per pot and logarithmic transformation values (log x + 1.1) are shown in
parentheses.
2. DAS = Days after sowing.
3. Number of millet plants in pots surviving at 107 DAS as percentage of total plants counted at 45 days.
4. Striga plants counted 90 DAS.
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