| Pearl Millet Diseases - Viral |
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Black streaked dwarf virus
Guinea grass mosaic virus
Indian peanut clump virus
Maize dwarf mosaic virus
Maize streak virus
Panicum mosaic virus
Satellite panicum mosaic virus
Wheat streak mosaic virus
Symptoms:
Stunting or dwarfing occurs, particularly when plants are infected in the seedling stage. Symptoms on pearl millet are not well-documented. On maize, white, waxy swellings occur on veins. Foliage is dark-green with chlorotic streaks and splitting of leaf margins (McGee 1988).
Pathogen and disease characteristics:
Belongs to Reoviridae fijivirus group (Park et al. 1994). Isometric particles are 75-80 nm in diameter (McGee 1988). Transmission occurs persistently by planthoppers.
Host range:
Pearl millet, corn, rice, finger millet, barnyardgrass, Isachne globosa, barley, wheat, barnyard millet, Digitaria sanguinali (Choi, Lee, and Ryu 1989, Choi, Park, and Park 1989), rye (McGee 1988)
Geographic distribution:
South Korea, Japan (on maize)
Nomenclature discrepancies:
Alternative names for the disease:
Rice black-streaked dwarf
Maize streaked dwarf
Seed transmission:
Not described in literature. Probably not seed transmitted (B.H. Choi, personal communication)
Primary citation(s):
As above
Symptoms:
Young diseased plants show lines of light green eye spots or a pale green mosaic, depending on cultivar. Symptoms develop into a striped mosaic by elongation and coalescing of the eye-spots. Some plants show severe symptoms with dwarfing.
Pathogen and disease characteristics:
The Potyvirus is transmitted by aphids (Hysteroneura setariae and Rhopalosiphum maidis), probably non-persistently, but can be mechanically transmitted. Symptoms appear about 8 to 10 days after inoculation. Strain/host specificity may exist.
Host range:
Pearl millet, Bromus commutatus, Bromus macrostachys, Panicum crusgalli, Panicum maximum, Sorghum aroundinaceum, Zea mays.
Possibly Paspalum conjugatum, Panicum maximum, Brachiaria brizantha, Brachiaria decumbens, Brachiaria dictyoneura, Brachiaria humidicola, Brachiaria jubata, Brachiaria ruzizensis (Morales et al. 1994). Also Brachiaria deflexa, Bromus arvensis, Bromus racemosus, Bromus sterilis, Coix lacryma-jobi, Echinochloa crus-galli, Oplismenus hirtelus, Panicum bulbosum, Panicum miliaceum, Paspalum racemosum, Setaria glaucum, Setaria italica, Setaria macrochaeta, Setaria verticillata, Stenotaphrum secondatum (Thouvenel et al. 1976).
Geographic distribution:
Ivory Coast (from pearl millet)
Possibly Columbia and Brazil on other hosts (Morales et al. 1994)
Nomenclature discrepancies:
None
Seed transmission:
Not known to be seed transmitted.
Primary citation(s):
(Kukla et al. 1984)
Symptoms:
Not described in the literature.
Pathogen and disease characteristics:
The furovirus is vectored by soil borne fungus Polymyxa spp.
Host range:
Pearl millet, peanut, finger millet (Eleusine coracana), foxtail millet (Setaria italica).
Geographic distribution:
Natural distribution on pearl millet is not known. Occurrence has been confirmed in India.
Nomenclature discrepancies:
None
Seed transmission:
Very low rate of seed transmission (0.9%) has been observed in plants that had been grown in an infested field in India.
Primary citation(s):
(Reddy et al. 1998)
Symptoms:
Infected plants express mosaic and mild stunting.
Pathogen and disease characteristics:
The potyvirus is generally aphid (non-persistent) or mechanically transmitted. Pearl millet is susceptible to "A" and "B" strains of MDMV. Symptom expression is not temperature sensitive. There appears to be strain specificity for some of the different hosts.
Host range:
Pearl millet, corn, sorghum, Johnsongrass, sudangrass, sand lovegrass, Indian grass, foxtail, barnyard grass, large crabgrass, downy bromegrass, goosegrass, wild cane, sugarcane, teosinte, foxtail millet, plumegrass, napiergrass, Chrysopogon montanus Trin., finger millet (Eleusine coracana (L.) Gaertn.), rice (Oryza sativa L.), Panicum miliaceum L., P. miliare Lamk., Paspalum scrobiculatum L., Themeda quadrivalvis O. Kuntze, Urochloa mosambicensis (Hackel) Dandy, U. stolonifera (Goosens) Chippind.
Geographic distribution:
"Widespread".
Nomenclature discrepancies:
Alternative names for the disease:
Sugarcane mosaic (This may be a different virus, see Krstic et al. 1995)
Grass mosaic
Bajra mosaic
Seed transmission:
Seed transmission in pearl millet has not been demonstrated. Very low frequency of seed transmission observed in corn.
Primary citation(s):
(Seth et al. 1972b, Rishi et al. 1973, Shurtleff 1980, Jensen et al. 1983)
Symptoms:
Chlorotic streaks on foliage are generally not severe. On inoculated seedlings, light colored circular spots develop, usually on one side of the leaf and parallel to the midrib. Spots coalesce to form nearly uninterrupted chlorotic bands running the length of the leaf. New emerging leaves show well-developed chlorotic stripes along the length of the leaf (Seth et al. 1972a).
Pathogen and disease characteristics:
Geminivirus transmitted by at least 8 leafhopper species.
Host range:
Pearl millet, corn, sugarcane, wheat, barley, oat, finger millet (Eleusine coracana), African rice (Oryza glaberrima Steudel), Axonopus compressus, Brachiaria lata, Brachiaria deflexa, Brachiaria distichophylla, Coix lachryma-jobi, Dactyloctenium aegyptium, Digitaria horizontalis, Eleusine indica, Echinochloa colonum, Echinochloa stagnina, Oryza sativa, Paspalum conjugatum, Paspalum notatum, Paspalum scrobiculatum, Panicum maximum, Pennisetum polystachion, Rhynchelytrum repens, Rottboellia cochinchinensis, Setaria barbata, and many other hosts within the Gramineae.
Geographic distribution:
Nigeria, Malawi, Uganda, South Africa, Egypt, India, Mauritius, Madagascar, and Reunion.
Nomenclature discrepancies:
Alternative names for the disease:
Pennisetum strain of maize streak virus.
Bajra streak
sugarcane streak virus
panicum streak virus
Numerous strains exist. Isolates from pearl millet cross react with antisera from corn, panicum and sugarcane isolates. Isolates from pearl millet probably belong to the Panicum strain, and appear to be too distantly related to MSV from maize to be important in relation to MSV in the field. Pearl millet susceptible to "Eleusine strain" (Nagaraju and Viswanath 1983). Later work (Briddon et al. 1996) indicates that isolates from pearl millet are most closely related to sugarcane streak virus.
Seed transmission:
Not known to be seed transmitted.
Primary citation(s):
(Shurtleff 1980, Nagaraju and Viswanath 1983, Mesfin et al. 1992)
Symptoms:
Symptoms on pearl millet are expressed as a mild chlorotic mottle (Qui et al. 1998). On switchgrass, stunting can be severe in susceptible plants. Mild green mosaic and mottling, Yellow or light green blotchy mottling, mosaic, and streaking of leaves are characteristic. The entire plant or sectors of it can become chlorotic if badly stunted (Sill and Pickett 1957).
Pathogen and disease characteristics:
109S isometric virus, 28-30 nm in diameter. Single RNA (28S) and protein species (28,000 daltons). Six serotypes have been differentiated. A serological relationship exists between PMV and members of the phleum mottle virus group (Buzen et al. 1984).
The virus is mechanically transmitted. PMV is a warm temperature virus. Incubation periods (7-18 days) are generally shorter at warmer, and longer at cooler temperatures. Optimum symptoms develop on many hosts with temperatures of 29 to 35 oC. Virus will remain infective in dessicated leaf tissue for up to 9 years (Sill and Talens 1962).
Host range:
Switchgrass (Panicum virgatum L.), broomcorn millet (P. miliaceum L.), ticklegrass (P. capillare L.), panicgrass (P. scribnerianum Nash), Hall's panicum (P. hallii Vasey), foxtail millet [Setaria italica (L.) Beauv], barnyard grass [Echinochloa crusgalli (L.) Beauv.], crabgrass [Digitaria sanguinalis (L.) Scop.] (Sill and Pickett 1957). Panicum ramosum, P. decompositum, P. turgidum, Setaria verticillata (Sill and Talens 1962). Setaria lutescens (Sill and Desai 1960). Maize (Zea mays), Panicum dichtomiflorum (Niblett et al. 1977). Panicum virgatum L. and St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) (Holcomb et al. 1989).
NOTE: Sill and Pickett (1957) indicate that pearl millet (P. glaucum) is immune to PMV. Buzen et al. (1984) indicated that PMV and its satellite virus were increased on pearl millet [Setaria italica (L.) Beauv.] (sic.). There was obviously a discrepancy in their host identification since S. italica is foxtail millet. Day et al. (1994) likewise referred to host plant as pearl millet. Day sent a voucher specimen to me (J. Wilson) and host was confirmed to be pearl millet. Masuta et al. (1987) indicate that pearl millet was used to increase PMV.
Geographic distribution:
Kansas. St. Augustine decline stain (PMV-SADV) occurs in Texas, Louisiana, Arkansas, South Carolina, and Mexico (Holcomb et al. 1989).
Nomenclature discrepancies:
Synonyms:
St. Augustine decline virus (SADV) is a strain of of PMV.
Seed transmission:
Generally not known to be seed transmitted (Sill and Desai 1960), however seed transmission of an SAD strain was reported in Setaria italica (Niblett et al. 1977)
Primary citation(s):
As indicated above.
Satellite Panicum Mosaic Virus
Symptoms:
Co-inoculation of Panicum Mosaic Virus (PMV) with its satellite virus (SPMV) results in a severe chlorotic mottle on pearl millet (Qui et al. 1988).
Pathogen and disease characteristics:
The virus is a mechanically transmitted 42S isometric particle, 17 nm in diameter. Not infectious alone. Contains two RNA species (14 and 34S) and a single protein species (15,500 daltons). Serologically unrelated to panicum mosaic virus (PMV), but dependent upon PMV for replication. Two serotypes are known (Buzen et al. 1984).
Host range:
Host range is not well defined, but probably identical to that of panicum mosaic virus.
See ANOTE@ in Panicum Mosaic Virus, page .
Geographic distribution:
Kansas.
Nomenclature discrepancies:
None
Seed transmission:
Not known to be seed transmitted
Primary citation(s):
As above.
Symptoms:
Systemic mosaic symptoms expressed as mosaic with interveinal reddening to mosaic with interveinal reddening and necrosis within the red areas.
Pathogen and disease characteristics:
Member of the Potyviridae, vectored by the wheat curl mite, Aceria tosichella Keifer. Mites more efficient at vectoring than mechanical inoculation.
Host range:
Pearl millet, sorghum, corn, barley, foxtail millet, wheat.
Geographic distribution:
Reported on pearl millet only from Kansas, USA.
Nomenclature discrepancies:
None.
Seed transmission:
Not known to be seed transmitted.
Primary citation(s):
(Seifers et al. 1996)
