Definitions for "Economic threshold"
the pathogen density at or above which the value of crop losses (in the absence of management efforts) would exceed the cost of management practices
the level of a pest population above which the amount of damage caused by the pest will exceed the cost of controlling that pest.
The pest density at which artificial control measures should be applied to prevent an increasing pest population from reaching the economic injury level; a threshold which tells the farmer when he must take action to prevent a pest outbreak.