Interaction of nutrients with rice diseases and insect pests: existing knowledge and research directions
2003
Castilla, N.P. | Savary, S.
We discuss the linkages between integrated disease and insect pest management on the one hand and integrated nutrient management on the other. This analysis involves three levels of integration: (1) at the plant level, the direct path linking plant morphology and physiology and injury, (2) at the crop or population level, the paths linking nutrients and damage via plant physiology, crop growth and development, and crop microenvironment, and (3) at the systems level, the overall interaction between plant nutrients and injury profiles. A review of the literature show that most existing knowledge pertains to the first level of integration only, in which the effects of the rate, timing of application, and form of nutrients on injuries are studied via the changes in plant anatomy ang physiology. Information at the population level is available only in a few examples - such as studies that analyze the relationships between the timing of nitrogen application and leaf blast, nitrogen rate and sheath blight, and nitrogen rate and leaffolders. Little information is available concerning the third level of integration. Although the existing knowledge base is essential, there is a need for a shift from reductionist to a systems approach to develop strategies to manage both nutrients and rice pests. A systems approach, involving controlled experiments, on-farm studies, and simulation modelling, can help in understanding and predicting the outcome of nutrient management strategies on injuries and yield, incorporating nutrient management in integrated pest management methods, and identifying research priorities for optimized nutrient management.
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