RA 00110.pdf - OAR@ICRISAT

Discussion
The five papers in this session dealt with three subjects:
diseases, insect pests, and beneficial microbial
associations with roots.
Diseases are generally an important constraint to
pearl millet production in Asia, and some years and
some locations are very important in West Africa. It
appears that downy mildew is the most important
disease, and the aggressiveness of this pathogen
appears to be greater in West Africa than in India.
Smut can be important in certain localities in both
India and West Africa. Under cooler conditions,
rust can become pronounced in both East and
southern Africa, and in India, especially after the
flowering stage. Much less is known about diseases
in East and southern Africa, although it is known
that all three diseases can be severe.
Downy mildew and ergot became important yield
reducers under farmers' conditions only after widespread
cultivation of hybrids in India in the early
1970s, a caution that should be borne in mind as
production of improved cultivars increases in Africa.
It would appear that insect pests are a greater
problem for pearl millet production in the Sahelian
region of West Africa than in the pearl milletgrowing
areas of India.
Two serious biological constraints to millet production
which were not dealt with in this session are
birds and Striga. Birds are an important problem in
the major pearl millet-growing areas of both Africa
and Asia, while Striga is an especially serious problem
in parts of Sahelian Africa. Solutions will not be
easy to find.
The use of rhizosphere-associated microbes to
enhance pearl millet growth is a research area that
could yield significant benefits. Certain soil bacteria
are known to fix atmospheric nitrogen, and mycorrhizae
enhance the availability of phosphorus. In
India, use of inoculum of associative nitrogen-fixing
bacteria is being recommended to pearl millet farmers.
However, before microbial associations can be
fully utilized by farmers to enhance pearl millet
growth, techniques to manipulate these organisms
must be developed so they can be used on a consistent
basis.
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