Download Selected text for Sweetpotato virus disease

Selected text for Sweetpotato virus disease
Preferred name
Sweetpotato virus disease
Identity (etiology)
This disease is caused by the synergistic interaction of two viruses: sweetpotato feathery
mottle potyvirus (SPFMV) and sweetpotato chlorotic stunt crinivirus (SPCSV).
Other names used
English: sweetpotato virus disease
Sweetpotato virus disease complex
Spanish: enfermedad viral del camote
Complejo viral del camote
Acronym: SPVD
Notes on taxonomy and nomenclature
SPVD is caused by the synergistic interaction of SPFMV and SPCSV. SPFMV is a
potyvirus transmitted by aphids in a non-persistent manner whereas SPCSV is a
crinivirus transmitted in a semi-persistent manner by the whitefly Bemisia tabaci.
Symptoms vary with plant genotype but typically include severely stunted plants with
small leaves, the latter often being distorted, narrow (strap-like) and crinkled, with a
chlorotic mosaic and/or vein-clearing, giving affected plant an overall pale appearance
(Gibson et al., 1998a; Gibson et al., 1998b).
Diagnostic methods
Indicator Host
The disease can be transmittd by grafting to :
Ipomoea batatas (TIB-8 sub-clone 9A or cv Porto Rico) – systemic vein chlorosis, leaf
distortion, “fan leaf”, and stunting of plants.
I. setosa – stunting, severe chlorosis followed by necrosis of older infected leaves, and a
severe reduction in leaf lamina.
Serological and Molecular Techniques
Both components of the disease can be detected and identified by ISEM and/or ELISA
using monoclonal or polyclonal antisera, or by NASH and PCR (see SPFMV and
SPCSV).
Geographic information
SPVD is common in Africa, where it is the main virus disease of sweet potato. Both
components of the disease have been found in many countries of Asia and South
America, in most cases together causing SPVD symptoms.
Biology and Ecology
This disease is caused by a synnergistic combination of SPFMV and SPCSV. A SPVDlike disease named “chlorotic dwarf (CD)” occurs in Argentina ( Di Feo et al., 1999).
However, CD is caused by the synergistic interaction of three viruses: two potyviruses
(SPFMV and SPMSV) and a crinivirus (SPCSV).
Seedborne aspects
None of the virus components are transmitted through the seed
Pathogen transmission
SPVD is transmitted by grafting. Individual viruses are transmitted by their vectors.
Economic impact
SPVD causes almost total yield loss in susceptible affected plants (Mukibi, 1977; Hahn
1979)
Phytosanitary risk
Risk criteria
Economic impact
Distribution
Seedborne incidence
Seed transmitted
Seed treatment
Transmission in planting materials
Transmission by vectors
Overall risk
Category
High
Worldwide
None
No
No
high
high
high
Control
The main measures to control SPVD is avoidance of diseased plants as sources of
planting material, sanitation, and use of resistant or tolerant cultivars.
REFERENCES
Clark CA, and Moyer JW, eds, 1988. Compendium of sweet potato diseases. Saint Paul,
MN, USA: APS Press.
Di Feo L, Nome SF, Biderbost E, Fuentes S, and Salazar LF, 1999. Etiology of sweet
potato chlorotic dwarf disease in Argentina. Plant Disease (in press).
Gibson RW, Kaitisha GC, Randrianaivoarivony JM, and Vetten HJ, 1998a. Identification
of the East African strain of sweet potato chlorotic stunt virus as a major component of
sweet potato virus disease in Southern Africa. Plant Disease, 82: 1063.
Gibson RW, Mpembe I, Alicai T, Carey EE, Mwanga ROM, Seal SE, and Vetten HJ,
1998b. Symptoms, aetiology and serological analysis of sweet potato virus disease in
Uganda. Plant pathology, 47: 95-102.
Hahn SK, 1979. Effect of viruses (SPVD) on growth and yield of sweet potato.
Experimental Agriculture, 15 252-256.
Mukiibi J, 1977. Effects of mosaic on the yield of sweet potatoes. In: Procedings of the
4th International Society for Tropical Root Crop. Cali, Columbia: CIAT, 169-170.
Schaefers GA, and Terry ER, 1976. Insect transmission of sweet potato disease agents in
Nigeria. Phytopathology 66, 642-645.