Panicum Mosaic Virus (PMV)
Symptoms: Symptoms on pearl millet are expressed as
a mild chlorotic mottle (Qiu et al. 1998).
On switchgrass, stunting can be severe in susceptible plants.
Mild green mosaic and mottling and 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 when temperatures are 29 to 35 °C. Virus remains
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.], barnyardgrass [Echinochloa crus-galli
(L.) Beauv.], crabgrass [Digitaria sanguinalis (L.) Scop.]
(Sill and Pickett 1957). Also Panicum
ramosum, P. decompositum, P. turgidum, Setaria verticillata
(Sill and Talens 1962), S. lutescens
(Sill and Desai 1960), maize (Zea
mays), Panicum dichtomiflorum (Niblett
et al. 1977), P. 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 the host as pearl millet. Day sent a voucher
specimen to me, and the host was confirmed to be pearl millet.
Masuta et al. (1987) indicate that
pearl millet was used to increase PMV.
Geographic distribution: USA (Kansas). St. Augustine
decline stain (PMV-SADV) occurs in the USA (Arkansas, Louisiana,
South Carolina, Texas), and Mexico (Holcomb
et al. 1989).
Nomenclature discrepancies: Synonyms: St. Augustine
decline virus (SADV) is a strain of PMV.
Seed transmission: Generally not known to be transmitted
by seed (Sill and Desai 1960); however,
transmission of an SADV strain by seed was reported in Setaria
italica (Niblett et al. 1977).
Primary citations: As indicated above.
Department of Agriculture
The material on this page is in the public
Original posting: June 5, 1999.