For high value commodities, the damage boundary may be very close to the gain threshold. Although the economic injury level (eil) and the economic threshold (et) are fundamental integrated pest management (ipm) concepts, they are often confused This is understandable, as the concepts are closely related and the definitions of eil and et can be expressed differently depending on context. Q) what happens to eil if control cost decreases Q) what happens to eil if market price increases Would you spray this field?
Even with its complications, the eil is fundamental for understanding the interaction of pests with their host, but the calculation of economic thresholds from these data is quite a different problem, which will be discussed in the next section. 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 threshold, like the economic injury level, is usually expressed in units of insect density or in terms of an injury measurement The economic threshold is always lower than the economic injury level in order to allow for sufficient time to enact control measures. Economic thresholds help to rationalise the use of pesticides and are one of the keys to profitable pest management
