文档介绍：Rational disease management in intensive and in extensive crops
Introduction
Factors governing the perceptions of growers while making disease management decisions
Modeling and decision making in low value crops and in in high value crops
Decision support systems
Concluding remarks
High value crops
The crop:
Factors govrening the perceptions of disease management
The crop:
Low value crops
Factors govrening the perceptions of disease management
The pathogen:
Factors govrening the perceptions of disease management
Destructive pathogen
Potato late blight (Phytophthora infestans)
Factors affecting disease management
The pathogen:
Moderately destructive pathogen
Potato early blight (Alternaria solani)
Destructive pathogen in high value crop
Value of the yield
Potential loss
Cost of disease management
2%
1%
High value crops are sprayed frequently
to minimize the risks of false negative action
Destructive pathogen in high value crop
Yield and costs per 1000 m2 of greenhouse tomatoes
Value of the yield
40,000 kg X $ = $10,000
Potential loss
$10,000 X 50% = $5,000
Cost of disease management
$5 spray X 20 = $100
Value of the yield
Potential loss
Cost of disease management
Management of moderately destructive pathogen in low value crop
13%
66%
Low value crops are not sprayed at all
to minimize the risks of false positive action
Management of moderately destructive pathogen in low value crop
Yield and costs per 1000 m2 of wheat crop
Value of the yield
500 kg X $ = $75
Potential loss
$75 X 20% = $15
Cost of disease management
$5 spray X 2 = $10
are sprayed frequently, even when protection is not needed. The result is surplus application of chemical pesticides
High value crops
The e
are not sprayed at all, even when protection is needed. The result is occasional occurrence of yield losses
Low value crops