Sorghum Diseases in India

Abstract
About 95% of the world's pearl millet (Pennisetum glaucum) growing area is located in Sahelian
and sub-Sahelian Africa and in the Indian subcontinent. The most important disease of pearl millet
is downy mildew, which is widespread. Second in importance is witchweed, especially Striga
hermonthica in African fields. Smut, ergot, and rust are also widespread, but of considerably less
importance. Bacterial and viral diseases are of minor importance and certainty of their identity is
often lacking. Nematodes are likewise probably widespread, but their importance in pearl millet
production is virtually unknown. Information on biology and epidemiology of the major diseases is
incomplete, and precise information on the environmental factors that promote disease is often
lacking. Field-screening techniques for downy mildew, smut, and ergot are available and stable
resistances have been identified. The importance of these three diseases in India has increased
considerably since the adoption of hybrids by Indian farmers. Differences in virulence have been
confirmed in pathogen populations of downy mildew and rust, but not in smut or ergot. Successful
resistance breeding has been achieved for downy mildew and smut, but it is problematic for ergot,
especially in hybrids. Confirmed resistance to S. hermonthica has not been found in pearl millet;
screening techniques need refinement.
Introduction
World Review of Pearl Millet Diseases:
Knowledge and Future Research Needs
Pearl millet [Pennisetum glaucum (L.) R. Br.] is the
staple cereal crop best suited to the harsh climate
of the seasonably hot, drought-prone,
semi-arid regions of Africa and the Indian subcontinent.
Average grain yields in the more than
27 million ha of pearl millet cultivated in
farmers' fields are estimated to be about 500 to
550 kg ha" 1 , although reported yields vary considerably
from one region to another and from
one year to another. The crop is grown for grain
mainly in Africa (more than 15 million ha, 95%
of which are in the Sahelian and sub-Sahelian
zones spanning from Sudan to Senegal), and the
Indian subcontinent (more than 11 million ha)
(ICRISAT 1987a). About 0.5 million ha are grown
S.B. King 1
in the southern USA, primarily for forage (ICRI­
SAT 1987b).
Smut and rust are widely distributed across
the pearl millet growing areas of the world, although
rust rarely occurs at more than a low
level in the Sahelian zone of Africa. Downy mildew
and ergot are widespread in the pearl millet
growing areas of Asia and Africa alike; but do
not occur on pearl millet in the Americas. The
downy mildew pathogen, Sclerospora graminicola,
has been reported, however, to occur naturally
on Setaria viridis, a common weed of corn
fields in parts of midwestern USA (Melhus et al.
1928). The distribution of a number of less important
leaf diseases of pearl millet is not well
defined. Two species of witchweed, Striga hermonthica
and S. asiatica, parasitize pearl millet;
1. Principal Plant Pathologist Cereals Program, ICRISAT Center, Patancheru, Andhra Pradesh 502 324, India.
King, S.B. 1992. World review of pearl millet diseases: knowledge and future research needs. Pages 95-108 in Sorghum and millets
diseases: a second world review. (de Milliano, W.A.J., Frederiksen, R.A., and Bengston, G.D., eds). Patancheru, A.P. 502 324, India:
International Crops Research Institute for the Semi-Arid Tropics. (CP 743).
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