The importance and implications of high health planting material for

The importance and implications of high health planting material for

The importance and implications
of high health planting material for
the Australian almond industry
by
Brendan Rodoni, Mirko Milinkovic and Fiona
Constable (Victorian DPI)
•Plant viruses and Perennial fruit trees
•Viruses of almonds in Australia
•High health planting material
•Almond and stone fruit biosecurity
•MT12005: Development of molecular diagnostic tools
for exotic and endemic pathogens of Prunus species
Plant viruses and Perennial fruit trees
Almonds
-Vegetative Propagated crop
- Lifespan approx. 20 years
• Once virus infected, the tree is infected for life
• The cumulative affects of early virus infection
are significant
Virus Transmission by Vegetative Propagation
Virus 1
Scion
(Budwood)
Rootstock
Virus 2
Prevention is the best cure
Plant clean material
Scion
(Budwood)
Rootstock
Repository of high
health planting material
- mother trees
Nurseryman uses
high health
planting material
for propagation
Grower plants
healthy trees
Viruses of almonds in Australia
•Prunus necrotic ringspot virus (PNRSV)
•Prune dwarf virus (PDV)
•Apple mosaic virus (ApMV)
•Apple chlorotic leafspot virus (ACLSV)
Europe:
•Mixed infections of ApMV, PDV and PNRSV cause “Almond mosaic”
•In Italy average crop losses in 12 major almond cultivars was 25% (2% - 50%)
(Martelli and Savino, 1997 Eppo Bulletin 27:525-534)
USA:
•In the USA PNRSV and related strains is the major virus associated with
reduced yields
Symptoms associated with virus infected almonds:
Symptoms on leaves include:
•Bright chrome-yellow (calico) pattern
•Chlorotic discolorations
•Localised necrosis (shot hole)
•Leaf curling
Additional symptoms include:
Bud failure
Rosetting
Stunting
Bushy growth
PNRSV infected Almond tree
leaf symptoms:
shot hole,
leaf curl
Symptoms on young leaves
-Leaf curl
-Marginal leaf necrosis
Rosetted growth
-Shortened internodes
-Bushy appearance
Symptoms on old leaves
-Chlorotic discoloration
- Leaf curl
Symptoms expressed on chip
bud inoculated GF305 indicators
in the screenhouse:
- Possible “ilarvirus”
High Health Planting Material for the
Australian Almond Industry
Almonds: Industry based - Almond Board of Australia
• PNRSV, PDV, ACLSV and ApMV
• 13 viruses, 2 viroids and 4 bacteria are present in Australia and can infect Almond
• Stone fruit: Individual nurseries with their own specified protocols for pathogen
testing (not compulsory)
• PNRSV, PDV, ACLSV
• Use of high health material is voluntary
The benefits of high health planting material to
the Australian almond industry include:
•A reliable supply of high health scion and
rootstock material for nurseries
•Provision of planting material to industry that will
produce consistent and high yielding trees for the
life of the orchard
High health planting material for the Australian almond
industry provides an important Biosecurity tool to
prevent establishment of new and exotic diseases in
Australia
You look so
hot today
Rhonda…...
Planting healthy trees is like “contents insurance”
for your home
Biosecurity is a priority for the Almond industry
“Biosecurity is about the protection of livelihoods, lifestyles and
the natural environment, which could be harmed by new pest
incursions. Biosecurity is a national priority ….”
(Orchard Biosecurity Manual for the Almond Industry )
“Safeguard industry production and marketing systems from potential
biosecurity threats “
(Australian Almonds Strategic R&D Plan 2011 – 2016 “Strategy 3.2”)
“Industry biosecurity strategies protect industry from risks posed
by pests through exclusion, eradication and control”
(Plant Health Australia)
New and emerging viruses – they do occur
AIDS - HIV
SARS
Bird Flu
Hendra virus – Vic Rail
Plum pox virus – Sharka
- A serious threat to the Australian almond industry
Spain: 800,000 trees destroyed during attempted eradication campaign
USA - Over 1000 acres of stone fruit orchard destroyed
Almond and stone fruit biosecurity
• Biosecurity continuum:
Natural protection from
exotic threats:
•Geographically isolated
•No shared land borders.
Active protection:
•National quarantine
system.
• Offshore:
– Accredited suppliers
• Adequate testing
• Border:
– Importation
• Post entry quarantine (PEQ)
• Illegal importation
• Onshore:
– Incursion management
– Interstate biosecurity
– Certification
• Requires rapid validated diagnostic tests for the detection of significant
pathogens
Border control: Importing Prunus germplasm into Australia
- Constable et al. 2011 – HAL project AL10001
Findings:
Pathogen
Bacteria
Phytoplasmas or
phytoplasma
groups
Viruses
Viroids
Fungi
•
Minimum of two years post entry quarantine (PEQ) testing
•
DAFF-Biosecurity (AQIS) do not currently differentiate between the
pathogens that infect different Prunus species
•
The current PEQ list requires updating to include recently described
pathogens
Number of pathogens
reported to infect
Prunus
Many
Number of quarantine
pathogens
Current
Proposed
2
4
Number of quarantine
pathogens proposed for
Almonds
3
Number of quarantine
pathogens proposed for
Stone Fruit
4
10
6
10
7
10
47
3
Many
13
1
70
34
2
75
10
1
25
34
2
50
Industry biosecurity plans: High priority
exotic threats
Almonds:
Summerfruit:
European stone fruit yellows
(Ca. Phytoplasma prunorum)
Almond brown line decline, and
Almond kernel shrivel
(Ca. Phytoplasma pyri)
Almond leaf scorch
(Xylella fastidiosa)
Hyperplastic canker
(Pseudomonas amygdali)
Plum pox or Sharka
(Plum pox virus)
X Disease
(X Disease Phytoplasma)
Phony peach or Plum leaf scald
(Xylella fastidiosa)
MT12005: Development of molecular diagnostic tools to
detect endemic and exotic pathogens of Prunus species
for Australia (2012-2015)
Project Aims:
•
Updated PEQ lists for Prunus species.
•
The development of validated molecular diagnostic tools under Australian
conditions
–
A post entry quarantine diagnostic manual for Prunus species
•
–
Specific protocols for almonds, summer fruit and cherries.
Improved understanding of the genetic variation of PNRSV, PDV, ApMV and ACLSV
•
–
•
Includes surveys to determine incidence and distribution of endemic pathogens and area freedom for exotic
pathogens
Improved diagnostic tests for certification
Recommendations for optimal pest and disease management strategies for
maintaining Prunus budwood repository blocks.
Acknowledgments
• Horticulture Australia Limited
• Victorian Department of Primary Industries
• Almond Board of Australia
• Summerfruit Australia
• Mark Whattam (DAFF-Biosecurity)