RA 00110.pdf - OAR@ICRISAT

diseases hitherto undescribed are currently being studied in addition to an undescribed stalk rot. Research in
Samaru, Nigeria, has provided evidence of pathogenic variation in Sclerospora graminicola, Striga hermonthica,
and Tolyposporium penicillariae. Millet lines resistant to downy mildew, smut, and ergot have been
identified in Nigeria. Many millet lines resistant to downy mildew elsewhere are highly susceptible to downy
mildew in Nigeria, while those resistant in Nigeria tend to maintain their resistance elsewhere. This and the fact
that most other diseases reported on pearl millet elsewhere are found in Nigeria make it an ideal location for
international millet pathology research.
Research on the Management of Pearl Millet Diseases in West Africa
(Recherches sur la maitrise des maladies du mil en Afrique de l'Ouest)
J.C. Selvaraj
FAO Plant Pathologist, C I L S S / I P M Project, B.P. 1820, Bamako, Mali
In West Africa downy mildew and smut cause appreciable yield loss in pearl millet. Ergot is potentially
dangerous, but not economically important at present. Seedling establishment failures due to seed and
soil-borne pathogens occur sporadically in all millet-growing areas.
The long-term management strategy to protect traditional millet production should be through a judicious
integration of host-plant resistance, seed treatment, and crop management practices.
In Mali, locations where downy mildew is economically important have been identified by annual surveys.
Experiments conducted in recent years show that good seedling establishment and control of downy mildew
leading to a 12-16% increase in yield can be obtained by seed treatment with an experimental formulation
containing 1.5 g metalaxyl + 0.625 g T M T D + 0.625 g Heptachlore a.i. kg -1 of seed. This has been verified and
demonstrated through a network of on-farm experiments, and the product is recommended for use in
locations where downy mildew is important. But in locations where downy mildew is not important, an
experimental formulation containing 0.5 g Benomyl + 0.625 g T M T D + 0.625 g Heptachlore a.i. kg - 1 seed
favored good seedling establishment and increased the number of productive tillers leading to a 10-12%
increase in yield. This product is superior to the currently used TMTD/Heptachlore.
Crop management research indicates that oospores play an important role in downy mildew epidemiology.
Cultural practices that reduce oospore production, dissemination, and infection could help reduce downy
mildew severity. Only limited success has been obtained in this area, and further studies are in progress.
Sporangia may play only a limited, but complementary role in downy mildew epidemiology in certain humid
locations in Mali. Sporangial infection can be reduced by frequent removal of all infected seedlings during the
first 30 d after sowing.
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