Who Needs Economic Thresholds?
In 1959 entomologists came up with definitions for concepts that had been used in pest control for many years. They defined economic damage as the amount of injury which will justify the cost of artificial control measures; the economic injury level as the lowest population density that will cause economic damage and the economic threshold as the density at which control measures should be initiated to prevent an increasing pest population from reaching the economic injury level. This unique combination of pest biology and economics theoretically gave growers the tool they needed to time pesticide applications to produce the greatest possible profits. Until the advent of the Economic Threshold (ET), sprays were applied in a preventive manner, usually on a calendar basis. For example, today is Monday, so I would spray the beans and tomatoes. The ET allows a grower to time sprays with the build-up of pest populations for more effective pest control. It avoids applying unnecessary sprays,