Date post: | 01-Jan-2016 |
Category: |
Documents |
Upload: | caleb-fleming |
View: | 59 times |
Download: | 0 times |
Pest Risk Analysis (PRA) Stage Pest Risk Analysis (PRA) Stage 2: Pest Risk Assessment2: Pest Risk Assessment
Pest Risk Analysis (PRA) TrainingPest Risk Analysis (PRA) Training
Stages
• Stage 1: Initiation• Stage 2: Pest Risk Assessment
– Step 1: Pest Categorization– Step 2: Assessment of the Probability
of Introduction (entry, establishment) and Spread
– Step 3: Impacts– Step 4: Overall Assessment of Risk– Step 5: Uncertainty
• Stage 3: Pest Risk Management
• Perpetuation, for the foreseeable future, of a pest within an area after entry (ISPM 5, 2007)
Establishment
Pest
Host (Habitat)
Environment(Ecosystem)
• Collect information from area(s) where pest occurs & PRA area– Pest information– Environment information– Host information
• Compare• Assess probability of establishment
Probability of establishment
• Availability of suitable hosts, alternate hosts and vectors
• Suitability of environment, including biotic & abiotic factors
• Cultural practices and control measures
• Other characteristics affecting probability of establishment
Factors to consider…
• Are hosts & alternates present? • Are habitats available for pest
plants?• How likely is the pest to find hosts?
Are they abundant? • Are hosts present in the vicinity of
expected entry points?
Host information
• Is the pest adaptable? • Has it been introduced elsewhere? • Can it adapt to different climatic or
other environmental factors? • Can the pest seek out hosts? Is it
mobile?
Pest information
• How does the pest reproduce? Does it have a high reproductive capacity?
• How does it survive adverse conditions?
• Does it require an alternate host or a vector?
Pest information
• Is a vector required for dispersal of the pest? – Is it present in the PRA area? – Is it likely to be introduced? – Are other potential vectors available?
Vector information
• Does the climate in the PRA area differ from that where the pest occurs? How?
• What climatic factors are critical for the pest’s success? What climatic factors, if any, are limiting?
• Is the climate suitable for the pest? Will it be able to survive? Will it be able to reproduce?
Climate information
Climate information
• Precipitation– Rain, snow, fog ….
• Temperature– Seasonal highs and lows, temperature
extremes …
• Seasonal variation
Other environmental information
• Soil• Hydrology• Vegetation• Prevailing winds• Day length• Species interactions
Cultural practices and control measures
• Compare cultivation practices of host crops in the area of origin and PRA area
• Would existing practices mitigate risk?• Are there any pest control programs or
natural enemies already in the PRA area?
• Are suitable methods for pest control or eradication available?
Other factors
• Reproductive strategy and method of pest survival – Self-crossing– Duration of life cycle– Generations per year
• Genetic adaptability• Minimum population needed for
successful establishment
Establishment
Pest
Host (Habitat)
Environment(Ecosystem)
Tools for predicting establishment
• Plant hardiness zone maps
• Climate maps• Climate-matching
models• Bio-climatic models
• Fit for purpose• Science-based• Transparent
Modelling systems
• Examples– CLIMEX– GARP– BIO-CLIM
• Distribution and abundance of an organism that cannot regulate its body temperature is largely determined by climate
• Climate information from the known distribution of an organism can help predict the potential distribution and abundance of the organism in new regions
Environmental factors
• The distribution and abundance of an organism that cannot control or regulate its body temperature is largely determined by climate.
• Climate information from the known distribution of an organism can help predict the potential distribution and abundance of the organism in new geographic regions.
CLIMEX
• Computer software containing long term data (30 years) from almost 3000 locations worldwide
• Is used to predict the effects of climate on plants and animals based on biological parameters e.g. response to temperature
• Generates a single number – the Eco-climatic Index to describe how favourable a location is for a particular species
Asian Longhorn BeetleAnoplophora glabripennis
• Native to China, pest of poplar trees
• Introductions in USA & Canada• PRA initiation for UK – spread
outside PRA area
Distribution in Asia
CLIMEX indices for ALB in Asia
CLIMEX Indices for ALB in Europe
Computerized predictive models
• Useful communication tool • Predictive maps based on limited climate
variables • Does not include host information or other
interactions• Involves subjective judgements &
assumptions• May cause false confidence
Suitability of environment
• Aphis nerii found at a nursery on imported plants
• Damages plants and vectors several viruses
• Polyphagous • Temperature requirements
known• Establishment in a protected
environment possible?
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
1 31 61 91 121 151 181 211 241 271 301 331 361
Julian date
Te
mp
(C
)
Heated max Heated min Outdoors max Outdoors min
Temperature data in relation to Aphis nerii development
Red = threshold temperature for development of Aphis nerii (8.2C)
Blue = outdoor maximum and minimum temperature data southern England
Black = maximum and minimum temperature in a heated glasshouse.
Sources of information• NPPO• RPPO• Atlases• WWW• FAO• CABI• Books• National government
data• Journals
• PRA area• Pest’s
current distribution
Establishment
Pest
Host (Habitat)
Environment(Ecosystem)