Virus Description and Distribution
Pepino mosaic virus (PepMV) is a member of genus Potexvirus which
infects mainly solanaceous plants, including tomato, potato and tobacco. It was
originally detected on pepino plants (Solanum muricatum) in Peru in 1974.
Since then, the virus was first reported on greenhouse tomato (Lycopersicon
esculentum) in the Netherlands and United Kingdom in 1999. Subsequently,
PepMV has been detected in several other European countries and North America.
In British Columbia, PepMV was first reported on greenhouse tomatoes in 2003.
Artificial inoculation studies have shown that PepMV can also infect potato (Solanum
tuberosum) and eggplant (Solanum melongena) but no evidence of
infection has been seen on pepper (Capsicum annum). Based on the PepMV
genomic RNA analysis, the North American strains (US genotypes), PepMV-US1 and
PepMV-US2, are closely related to each other but they differ from the European (EU
tomato genotype), Chilean (CH2 genotype) and Peruvian (LP genotype) strains.
PepMV is considered as a highly infectious and readily transmittable and it
systemically infects tomato.
Symptoms
PepMV can cause various symptoms in tomato. Reports on the disease severity
of infected plants vary from minor to severe depending on the type of PepMV
strain, age, vigour and variety of tomato plant and climatic/growing conditions.
Symptoms are often expressed during fall and winter months when temperatures and
light levels (daylight) are minimal. Initial symptoms usually appear 2-3 weeks
after infection. Early symptoms are noticeable on the
growing terminals (heads) of infected plants with light-green, thin or
needle-like leaves and stunted growth. On leaves (figures 1 & 2), symptoms
appear as yellow angular spots and bubbly areas, mild interveinal chlorosis
(yellowing) and leaf distortions such as spindly leaves. Streaks of browning may
appear on stems and flowering clusters that may affect the development of
flowers and fruits. Fruits sometimes show discoloration of yellow-red mosaic
patterns, called marbling (figures 3 & 4), and may lead to uneven fruit ripening.
Severely affected plants become stunted and distorted. Recent studies conducted
in the United Kingdom showed that PepMV was not found to reduce the bulk yield
but the quality of tomato fruit was reduced significantly. Loss of quality was
mainly due to reduced fruit size, blotchy ripening, marbling, and spotting.
Figure 1: Leaf symptoms on tomato plants
infected with Pepino mosaic
virus. |
Figure 2: Leaf symptoms on tomato plants
infected with Pepino mosaic
virus. |
Figure 3: Fruit symptoms on tomato
plant infected with Pepino mosaic
virus. |
Figure 4: Fruit symptoms on tomato
plant infected with Pepino mosaic
virus. |
Spread
PepMV is transmitted mechanically, particularly by contact. PepMV appears to
spread at a much faster rate than the other known potexviruses such as Tomato
mosaic virus (ToMV) and Potato virus X (PVX). PepMV is readily
transmitted by contaminated tools, workers’ hands and clothing. Direct
plant-to-plant contact and propagation by grafting can also spread the virus.
Recent studies, in 2007 and 2008, reveal that PepMV can be transmitted by seeds
obtained from infected tomato plants. However, the rate of transmission of PepMV
from seed to growing embryo is low (0.005 – 0.057%), depending on the harvest
interval of seeds obtained from infected mother plants. A similar study in 2005
suggested that PepMV may be seed-borne, but it could only be detected in the
seed coat and not in the embryo. A report from the Netherlands claims that PepMV
can only be detected in poorly cleaned fresh seed and the virus was never
detected in well cleaned seed. Its ability to spread through recirculating
irrigation systems is unknown.
Control
Since PepMV is spread chiefly by contact, control
strategies for PepMV are strictly focused on sanitation and overall biosecurity
measures. Plant removal, restricted access to affected rows, sanitation of
workers (particularly hands and clothing) and tools are all critical. Dipping
hands and tools in skim milk prior to and after working with each plant has been
reported to reduce transmission of the virus. For details on control measures,
greenhouse sanitation and biosecurity please refer the factsheets on “Management
of Pepino Mosaic Virus in Greenhouse Tomatoes”, “On-Farm
and Greenhouse Sanitation and Disinfection Practices” and “Biosecurity
Guidelines” respectively.
References
- Córdoba-Sellės, M.C, Garcîa-Rández, A., Alfaro-Fernández, A. and
Jordó-Gutiérrez, C. (2007). Seed transmission of Pepino mosaic virus
and efficacy of tomato seed disinfection treatments. Plant Diseases 91 (10),
1250-1254.
- Córdoba-Sellės, M.C., Martínez-Priego, L. and Jordó-Gutiérrez, C.
(2004). New natural hosts of Pepino mosaic virus in Spain. Plant
Disease 88, 906.
- French, C.J., Bouthiller, M., Bernardy, M., Ferguson, G., Sabourin, M.,
Johnson, R.C., Mastetrs, C., Godkin, S. and Mumford, R. (2001). First report
of Pepino mosaic virus in Canada and the United States. Plant Disease
85, 1121.
- Hanssen, I.M., Paeleman, A., Wittemans, L, Goen, K., Lievens, B.,
Bragard, C., Vanachter, A.C.R.C. and Thomma, B.P.H.J. (2008). Genetic
characterization of Pepino mosaic virus isolates from Belgian
greenhouse tomatoes reveals genetic recombination. European journal of Plant
Pathology 121, 131-146.
- Jones, R.A.C., Koenig, R. and Lesemann, D.E. (1980). Pepino mosaic
virus, a new potexvirus from pepino (Solanum muricatum).
Annals of Applied Biology 94, 61-68.
- Ling, K. and carpenter, L. (2005). Pepino mosaic virus, an
emerging disease in tomato greenhouse production worldwide; is seed
responsible? Proc 1 sr IC on tomato diseases. Eds. M.T. Momal, Ji, P. and
Jones, J.B. Acta Horticultura 695. ISHS 2005.
- Maroon-Lango, C.J., Guaragna, M.A., Jordan, R.L., Hammond, J., Bandla,
M. and Marquardt, S.K. (2005). Two unique US isolates of Pepino mosaic
virus from a limited source of pooled tomato tissue are distinct from
the third (European-like) US isolate. Archives of Virology 150 (6),
1187-1201.
- Pagan, I, Córdoba-Sellės, M.C., Martínez-Priego, L., Fraile, A., Malpica,
J.M., Jorda, C. and Garcia-Arenal, F. (2006). Genetic structure of the
population of Pepino mosaic virus infecting tomato crops in Spain.
Phytopathology 96 (3), 274-279.
- Pospieszny, H. and Borodynko, N. (2006). New Polish isolate of Pepino
mosaic virus highly distinct from European tomato, Peruvian, and US2
strains. Plant Disease 90 (8), 1106.
- Soler, S., Prohens, J., Diez, M.J., and Nuez, E. (2002). Natural
occurrence of Pepino mosaic virus in Lycopersicon species in
Central and Southern Peru. Journal of Phytopathology 150 (2), 45-53.
- Spence, N.J., Basham, J. Mumford, R.A. Hayman, G. Edmondson, R. and
Jones, D.R. (2006). Effect of Pepino mosaic virus on the yield and
quality of glasshouse-grown tomatoes in the UK. Plant Pathology 55 (5),
595-606.
- van der Vlugt, R.A.A., Stijger, C.C.M.M., Verhoeven, J.J.Th.,J.,
Verhoeven, J. and Lesemann, D.E. (2000). First report of Pepino mosaic
virus on tomato. Plant Disease 84 (1), 103.
- Seed transmission of Pepino mosaic virus in tomato:
<http://www.pepeira.wur.nl/>
<http://www.ishs.org/news/?p=121>
Prepared by:
Dr. Siva Sabaratnam
Plant Pathologist
Abbotsford Agriculture Centre,
Ministry of Agriculture & Lands
Abbotsford, B.C.
September 2008
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