Diagnostic Tool



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Here are a few terms that will frequently be used in this module:  


Ecology is the study of the interrelationships of organisms and their surrounding environment. In other words, ecology is the study of how organisms interact with their abiotic and biotic environment.   

Abiotic Components

Abiotic components are the non-living components of the environment such as space and weather. Pesticides could also be considered an abiotic factor.   

Biotic Components

Biotic components of the environment are living organisms. Biotic components of the environment include primary producers (e.g., rice plants), herbivores (e.g., rice insect pests), natural enemies of rice pests (e.g. parasitoids, predators, pathogens) and competitors (individuals of the same or different species competing for resources).


Habitat is the environment in which the individual organism lives.


A species is a group of reproductively isolated organisms. It is the basic unit of taxonomic classification of organisms, designated in scientific nomenclature by a unique Latin binomial with a genus and specific epithet. For example the scientific name of the rice yellow stem borer is Scirpophaga incertulas.  


Population is a group of individuals of the same species occupying a distinct space.    


Community is the species that occur together in space and time.

Ecological Niche

Ecological niche is all the components of the habitat with which an organism or population interacts.


Pest is an organism that interferes with the availability, quality or value of a managed resource. In an agronomical sense a pest is any organism or microbe with the potential to lower the value of a crop by reducing crop yield, quality or reproductive ability (e.g. storage pests that reduce seed viability).

Integrated Pest Management (IPM)

IPM is an ecosystem-based pest management strategy that focuses on long-term prevention of pests and their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant cultivars. Pesticides are used only when needed as determined by established guidelines.

Economic Injury Level (EIL)

EIL is the lowest population density of a pest that will cause economic damage to a crop. Sometimes referred to as the “damage threshold”

Economic Threshold Level (ETL)

ETL is the pest population level at which a control action, such as pesticide application, should be considered in order to prevent economic loss. ETL is synonymous with “action threshold” or “treatment threshold”. At the ETL, the economic return of the control effort is greater than the cost of control.  

Ecology and Pest Management

IPM introduced ecological thinking into crop protection. Ecology gives context to pest management; otherwise there would be a hodgepodge of treatments put together for pest control. No longer do we think of "pest control" simply to reduce crop damage, rather we are concerned with the prevention of outbreaks of pests. Why do pest outbreaks occur? Pest outbreaks usually occur if the normal equilibrium of populations is disturbed by natural disasters (e.g., drought, floods, fire), crop management (e.g., removal of natural enemies by insecticides, over-use of nitrogen); or massive pest immigrations.

Some of the ways we can improve pest management include:

  • Reducing pest levels –  e.g., using insecticides, cultural practices
  • Improving natural enemy levels – e.g., establishing refuges
  • Improving resistance of the plant to pest attacks (e.g. nutrient management and breeding for host plant resistance to pest)

It is important to know what limits pest population growth. Abundance of resources and natural enemies influence pest abundance. In the context of management it is also important to know the most vulnerable stage of the pest population.