The document discusses key concepts in economic entomology, including injury, damage, economic levels, economic thresholds, and economic injury levels. It defines injury as physical harm to a commodity caused by a pest, while damage refers to the monetary value lost due to injury. The economic level is the pest population level at which control actions must be taken to prevent quality or yield loss. The economic threshold is the pest density at which management should occur to prevent populations reaching the economic injury level, which is the lowest pest population that causes economic damage and justifies the cost of control.

1. Economic ConceptEconomic Concept
of Pestof Pest
ManagementManagement
Prepared by :Prepared by :
Asuncion, Fritz JaycoAsuncion, Fritz Jayco
Celebria, DeeJaneCelebria, DeeJane
Cueno, RealynCueno, Realyn
Cortez, Mona KarllaineCortez, Mona Karllaine
Domiños, Helen GraceDomiños, Helen Grace

2. Economic EntomologyEconomic Entomology
 The scientific study ofThe scientific study of
pests and pest controlpests and pest control
strategies in recognitionstrategies in recognition
of the financial impactof the financial impact
insects have on industry,insects have on industry,
agriculture and humanagriculture and human
society in general.society in general.

3. Injury vs. DamageInjury vs. Damage
 InjuryInjury
is the physical harm oris the physical harm or
destruction to a valueddestruction to a valued
commodity caused by thecommodity caused by the
presence or activities of apresence or activities of a
pest.pest.

4. Injury vs. DamageInjury vs. Damage
 DamageDamage
is the monetary valueis the monetary value
lost to the commodity as alost to the commodity as a
result of injury by the pest.result of injury by the pest.

5. Economic LevelEconomic Level
 It is the level of the pest population, asIt is the level of the pest population, as
determined by valid samplingdetermined by valid sampling
procedures, at which some additionalprocedures, at which some additional
control or management practice must becontrol or management practice must be
used to prevent yield or quality loss.used to prevent yield or quality loss.

6. Economic LevelEconomic Level
Two factors influencing the use ofTwo factors influencing the use of
economic levels by growers :economic levels by growers :
 Federal regulationsFederal regulations
 Market pricesMarket prices

7. Economic ThresholdEconomic Threshold
Level (ETL)Level (ETL)
 Entomologist define aEntomologist define a
point below thepoint below the
economic injury level ateconomic injury level at
which a decision is madewhich a decision is made
to treat or not to treat.to treat or not to treat.
 The pest density atThe pest density at
which managementwhich management
action should be taken toaction should be taken to
prevent an increasingprevent an increasing
pest population frompest population from
reaching the Economicreaching the Economic
Injury Level.Injury Level.

8. Economic ThresholdEconomic Threshold
Level (ETL)Level (ETL)
 To calculate theTo calculate the
Economic ThresholdEconomic Threshold
Level you must :Level you must :
 Know how to identifyKnow how to identify
the pestthe pest
 Know how to sampleKnow how to sample
the crop environmentthe crop environment

9. Economic ThresholdEconomic Threshold
Level (ETL)Level (ETL)
 (computation)(computation)

10. Economic ThresholdEconomic Threshold
Level (ETL)Level (ETL)
 Sex pheromoneSex pheromone
trapstraps
 Sweepnet SamplesSweepnet Samples

11. Economic Injury LevelEconomic Injury Level
(EIL)(EIL)
 – “The lowest
population density of
a pest that will cause
economic damage;
or the amount of pest
injury which will
justify the cost of
control.”(Stern et al.,
1959)

12. Economic Injury LevelEconomic Injury Level
(EIL)(EIL)
 The economic injury level (EIL) isThe economic injury level (EIL) is
often expressed mathematicallyoften expressed mathematically
by the formula:by the formula:
 where:where:
CC = is the unit cost of= is the unit cost of
controlling thecontrolling the pest (e.g.,pest (e.g.,
1000/acre)1000/acre)
NN = is the number of pests= is the number of pests
injuring the commodityinjuring the commodity unitunit
(e.g., 800/acre)(e.g., 800/acre)
VV = is the unit value of the= is the unit value of the
commodity (e.g.,commodity (e.g.,
23500/acre)23500/acre)
II = is the percentage of the= is the percentage of the
commodity unitcommodity unit injuredinjured
(e.g., 10% loss)(e.g., 10% loss)

13. Economic Injury LevelEconomic Injury Level
(EIL)(EIL)
 For the exampleFor the example
given above, thegiven above, the
economic injury leveleconomic injury level
would equal towould equal to
insects per acre.insects per acre.

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