Agriculture Reference
In-Depth Information
The leaf scorching symptoms caused by
Xylella
may be
confused with moisture stress, salt toxicity or herbicide
injury, while interveinal chlorosis caused by CVC
resembles symptoms of zinc deficiency.
(Cercopidae). A species of leaf hopper, the glassy-winged
sharpshooter,
Homalodisca coagulata
, has been largely
responsible for major outbreaks of Pierce's disease of
grapevine in California since the insect invaded the
region in the 1990s.
Source of infection and spread
The pathogen resides in the xylem vessels of infected
plants. It can be transmitted by grafting and by many
species of sap-sucking leaf hoppers, with the most
important vectors in North America being
sharpshooters (Cicadellinae) and spittle bugs
After feeding on infected plants for several hours, the
leaf hoppers are then able to transmit the pathogen for
the remainder of their life.
The movement of infected planting material for graft
propagation or the movement of insect vectors can spread
the pathogen between countries and regions. The CVC
strain of
Xylella fastidiosa
is also carried in citrus peel,
flesh and seeds.
What to do if you suspect
Xylella fastidiosa
This pathogen is a biosecurity risk to Australia. Any
suspected affected plants should be reported to the nearest
Department of Primary Industries or the Plant Health
Australia hotline (1800 084 881).
Further information
A g r i o s G N ( 2 0 0 5 )
Plant pathology
(5th edn). Elsevier
Academic Press: New York.
H o p k i n s D L & P u r c e l l A H ( 2 0 0 2 )
Xylella fastidiosa
:
cause of Pierce's disease of grapevine and other emergent
diseases.
Plant Disease
86
, 1056 - 1066.
S c h a a d N W , P o s t n i k o v a E , L a c y G , F a t m i M & C h a n g
C J ( 2 0 0 4 )
Xylella fastidiosa
subspecies:
Xylella fastidiosa
subsp.
piercei
, subsp.
nov
.,
Xylella fastidiosa
subsp.
multiplex
subsp.
nov
., and
Xylella fastidiosa
subsp.
pauca
subsp.
nov
.
Systematic and Applied Microbiology
27
, 2 9 0 - 3 0 0 .
Fig 2.33 CVC symptoms showing smaller fruit (above). Lower fruit
healthy.
