农业植物病害IPM（英文）- (7).ppt

Prediction of disease outbreaks
Introduction
Principles of disease forecasting
Forecasting the amount of initial inoculum
Forecasting the rate of pathogen proliferation
Forecasting host response
Concluding remarks
Why do we need to predict disease outbreaks?orWhat are the uses of disease forecasts ?
For making strategic decisions
Prediction of the risks involved in planting a certain crop.
Deciding about the need to apply strategic control measures (soil treatment, planting a resistant cultivar, etc.)
Time
Disease intensity
For making tactical decisions
Deciding about the need to implement disease management measure
?
The disease pyramid
grower
pathogen
environment
host
The principles of disease forecasting are based on:
The nature of the pathogen
Effects of the environment
The response of the host to infection
Activities of the growers
The disease pyramid
grower
pathogen
environment
host
disease
Time
Disease severity (%)
Monocyclic pathogens
Time
Disease severity (logit)
Time
Disease severity (%)
Polycyclic pathogens
Initial disease
rate
Monocyclic pathogens
Complete only one disease cycle in a growing season
(100 - y)
QR
dy
dt
Q = amount of initial inoculum
R = infection efficacy of the inoculum
y = disease intensity
Prediction of a monocyclic pathogen plete only one disease cycle in a growing season - indirect prediction
Severe infections occur after moderate winters.
Mild infections occur after cold winters.
Average Temp. in December, January and February

High probability for severe epidemic
-
Low probability for severe epidemic
Wilt disease in maize induced by Erwinia stewartii
Consequences from predicting the severity of Erwinia stewartii in maize on grower’s action
High probability for severe epidemic
Do not sow maizeat all
Sow only resistant cultivars
Low probability for severe epidemic
Sow maize as planned
Prediction of a monocyclic pathogen plete only one disease cycle in a growing sea