Symptoms: Immature, green sori larger than the seed develop on panicles during grain fill. A single sorus develops per floret. As grain matures, sori change in color from green to dark brown. Sori are filled with dark teliospores.
Pathogen and disease characteristics: Chestnut brown to black-brown sporeballs are composed of 200 to 1,400 aggregated yellowish brown globose to subglobose teliospores. Teliospores germinate to produce promycelia with basidiospores and sporidia (Subba Rao and Thakur 1983). Infection occurs when sporidia suspended in rain or dew infiltrate into the boot (Wilson 1995). Aerial populations of sporidia are greatest when minimum and maximum temperatures range between approximately 21 and 31 °C and maximum relative humidity is greater than 80 percent (Kousik et al. 1988).
Host range: Pearl millet.
Geographic distribution: United States (Wells et al. 1963), India, Zimbabwe, Senegal, Chad, Niger, Nigeria, Malawi (Wiehe 1953, Saccas 1954, King 1970, Jouan and Delassus 1971, Rachie and Majmudar 1980), and Tanzania (Mbwaga et al. 1993). Also Zambia, Sudan, Cameroon, Burkina Faso, Ghana, Mali (S.B. King, personal communication, 1995).
Nomenclature discrepancies: Synonyms: Tolyposporium penicillariae Bref. (Vanky 1977), Tolyposporium senegalense Speng.
Considerable confusion exists in the literature concerning smut of pearl millet. For further details, see "Questionable or poorly described diseases of pearl millet reported in the literature."
Seed transmission: Seed may be infested with teliospore balls, but infection does not take place through seedlings (Bhatt 1946). Teliospores may remain viable in the soil, where basidiospores and sporidia may be produced (Patel et al. 1959).
Primary citations: As indicated above.
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Original posting: June 5, 1999.