Wheat Dwarf Virus in - NJF

Wheat Dwarf Virus in Sweden
Roland Sigvald
Swedish University of Agricultural Sciences
NJF seminar at Bäckaskog 9 -11 October, 2007

Background
• Wheat Dvarf Virus (WDV) caused great yield
reduction in winter wheat in some years during the
period 1900-1960
• In 1996 wheat plants infected with WDV were
observed in some fields in central Sweden.
Following year in 1997, more that 100 winter wheat
fields were damaged in central Sweden
• In 1997 yield reduction was estimated to 10-30% in
many fields in central Sweden. In some fields the
reduction was more than 60%

• WDV is transmitted by Psammotettix alienus. Virus is not
transmitted by Javesella pellucida, Laodelphax striatellus,
Macrosteles laevis
• Virus is transmitted in a persistent manner; retained when
the vector moults; does not replicate in the vector; not
transmitted congenitally to the progeny of the vector
• Susceptible host species are found in the Family Gramineae.
The following species were susceptible to experimental virus
infection: Avena sativa, Avena strigosa, Bromus secalinus,
Hordeum vulgare, Lagurus ovatus, Lolium multiflorum, Lolium
perenne, Lolium remotum, Lolium temulentum, Poa annua,
Secale cereale, Triticum aestivum, Triticum durum.

Winter wheat plants infected with WDV, Uppland 2006

Psammotettix alienus in yellow water traps in
Uppland 2006
25
20
15
10
5
0
20060509
20060522
20060605
20060620
20060703
20060822
20060905
20060918
20061002
20061016
nymfer
vuxna

80
70
60
50
40
30
20
10
0
WDV infected Psammotetttix alienus, autumn 2004 in central
Sweden
Badentorp
Britehov
Brunnby
Fyrisvall
Hacksta
Haga
Ölsta
Ystad, E
Norsholm, E
Tåby
Ant. Stritar tot.
Antal positiva

• Occurrence of vectors
Risk assessment
• Proportion of virusinfected vectors
• Occurrence of virus sources
• Date of sowing winter wheat
• Weather
• Variety