climate and the risk of pests and disease primary research activities in this area: 1.participatory...
TRANSCRIPT
Climate and the risk of pests and disease
Primary research activities in this area:
1. Participatory evaluations of risk for potato tuber moth and Andean potato weevil in relation to climate parameters in the Altiplano
2. Evaluation of climate and the utility of crop diversification for disease management
3. Integrated predictions of future risk for potato tuber moth and potato late blight based on climate change predictions
Climate and the risk of pests and disease
Primary research activities in this area:
1. Participatory evaluations of risk for potato tuber moth and Andean potato weevil in relation to climate parameters in the Altiplano
2. Evaluation of climate and the utility of crop diversification for disease management
3. Integrated predictions of future risk for potato tuber moth and potato late blight based on climate change predictions
From the LTRA-4 participatory community assessment:
Farmers in our study area of the Bolivian altiplano perceive pest problems to be increasing, along with increasing resistance to pesticides
They identified potato tuber moth and Andean potato weevil as priority constraints to production
Objectives:
Estimate Andean potato weevil and potato tuber moth risk in three communities in each of Umala and Ancoraimes, Bolivia (expanding to Puno, Peru)
Link pest risk with climate and socioeconomic factors
Methods:
Measure pest populations in a study field in each of three communities in each of two regions across three years
Use a ‘windows’ approach to evaluate time intervals that impact pest population growth in the field
Evaluate the relationship between risk and climate variables across years using the site-year combinations as replicates
Pitfall traps used for sampling Andean potato weevil
Pheromone traps used for sampling potato tuber moth
0
20
40
60
80
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Semanas
Nº d
e ad
ulto
s
-2
13
28
Tem
p. M
áx. y
m
ín.
Premnotrypes sp Rigopsidius piercei Tº máx Tº mín
Example data set from one community: Andean potato weevil 2006-2007 in the community Jatuquira: Number of adults of two species with maximum temperature and minimum temperature
0,02
0,53
0,29
1,7
0 0,01
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
Pro
me
dio
de
ad
ult
os
Vinto Coopani Jatuquira San Jose de Llanga
Premnotrypes spp Rhigopsidius piercei
Andean potato weevil 2006-2007 in three communities in Umala: The average number of adults retrieved from traps
Climate and pest populations
As we gather more site-year observations and compare summary statistics, we are populating this figure for different combinations of climate statistics
Associated socioeconomic and management data will provide context
Climate summary statistic for one season
Pop
ulat
ion
for
one
seas
on
Each point indicates the result from one community in one season
Climate and the risk of pests and disease
Primary research activities in this area:
1. Participatory evaluations of risk for potato tuber moth and Andean potato weevil in relation to climate parameters in the Altiplano
2. Evaluation of climate and the utility of crop diversification for disease management
3. Integrated predictions of future risk for potato tuber moth and potato late blight based on climate change predictions
Reg
iona
l ino
culu
mlo
ad
Year-round host availability
Short season of host availability
Time through year
Dry season
Host available
Reg
iona
l ino
culu
mlo
ad
Year-round host availability
Short season of host availability
Time through year
Dry season
Host available
How does season length influence disease risk?
Analysis in collaboration with the International Potato Center
Garrett et al., in revision for Ecological Applications
Use of potato cultivar mixtures can reduce the risk of potato late blight
Garrett and Mundt 2000
Time
What is the effect of season length on the utility of potato mixtures to manage disease?
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Predicted regional inoculum load (increasing)
RM
R
Corvallis HuancayoLa Niña
HuancayoEl Niño
CajamarcaLa Niña
CajamarcaEl Niño
Quito
Increasing season length
RMR <1 indicates a benefit from mixtures
Garrett et al., in revision
Climate and the risk of pests and disease
Primary research activities in this area:
1. Participatory evaluations of risk for potato tuber moth and Andean potato weevil in relation to climate parameters in the Altiplano
2. Evaluation of climate and the utility of crop diversification for disease management
3. Integrated predictions of future risk for potato tuber moth and potato late blight based on climate change predictions
Estimates of potato late blight risk in the altiplano
1995-1998: No disease predicted
2001-2004: …
We are using GIS to map risk predicted from disease and pest risk forecasting models
There are also models of weather effects on potato tuber moth that we will draw on for modeling that system
Estimates of disease and pest risk in the altiplano
We are developing risk maps for late blight under climate change scenarios based on existing models of the relationship between climate variables and epidemiology
Sporleder et al. 2004
Potato tuber moth response to temperature in controlled environment experiments:
Development rates for larvae and pupae
Developing a conceptual framework for the impacts of global change on cropping system constraints...
to guide strategies...
An early version of assessment of biological relationships follows– this might function as one component of a more complete model– even limited to biology, there are interactions across all scales
Garrett et al. 2006
Garrett et al. 2006
Evaluation of thresholds, interactions, and positive feedback loops
A small change in temperature or precipitation does not necessarily imply a small change in disease risk
Examples from epidemics follow
Also need to consider interactions between changes in disease and pest risk and human capabilities for management
Garrett 2008
The local inoculum load builds during the period of conducive weather
0
10
20
30
40
50
60
70
Month 1 Month 2 Month 3 Month 4 Month 5 Month 6 Month 7Per
cent
age
inoc
ulum
sat
urat
ion
Because plant disease pressure often increases following a compound interest model, increasing the length of the growing season slightly can have a very large impact on inoculum load
An Allee effect may produce thresholds for pathogen reproduction
(Allee effect = lower per capita reproduction in small populations)
0
20
40
60
80
100
120
Per
cap
ita r
epro
duct
ion
Allee thresholds may produce larger impacts from climate shifts than would be anticipated with partial knowledge
Garrett and Bowden 2002
Pathogen population size
0
20
40
60
80
100
120
Feedback loops for disease management
Management based on controlling local inoculum production becomes less useful as regional inoculum loads rise
•Field sanitation•Intercropping and mixtures•Resistance based on lower inoculum productionU
tility
of
loca
l man
agem
ent
Regional inoculum load
Responding to climate changeWe are developing an integrated framework for evaluating
responses to climate change for any given disease or pest
Characterization of resources and needs in areas such as the following, at all relevant scales:
-Plant genetic resources for resistance and issues for their deployment
-Producer knowledge and resources, and training systems
-Historic and predicted population characteristics for pathogens, vectors, and biocontrol agents
-Historic and predicted climate characteristics
-The nature of interactions between these areas
Then: Validating the conceptual model