Chapter 7: Economic Decision Levels Flashcards
What is the concept of Economic-Injury Level
determines what all counts as a insect damage, how to measure damage, encourages more rational use of insecticides, avoids insecticide resistance
Integrated Control
Replacement for only spraying insecticides, focuses on a well rounded approach
Economic damage
amount of injury that will justify the cost of artificial control measures
Injury
effect of pest activities on host physiology that is usually deleterious (pest activity focused)
Damage
measurable loss of utility, often including yield quantity, quality, or aesthetics (crop/plant focused)
when do insects become a problem
the money required for suppressing insect injury = potential monetary loss from the pest population
gain threshold
beginning point of economic damage
Damage boundary
lowest level of injury where damage can be measured - usually reaches before economic damage occurs
Economic injury level
the lowest number of insects that will cause economic damage
insect equivalents
the amount of damage one insect is doing through its entire lifespan
EIL calculations
Cost of management per area, Economic impact level
Economic threshold
the number of insects (density or intensity) that should trigger management action to prevent reaching the EIL
Fixed economic threshold
percentage of EIL is fixed
Descriptive economic threshold
takes into account possible changes in the pest population growth rate
Market Value
Crop Value
Management Costs
Cost of suppressing a pest population must be estimated before profitability of an action can be assessed
Degree of injury per insect
Determined by insect and host plants
stand reducers
insects that reduce stand (plant biomass)
Leaf-mass consumers
insects that consume leaf matter, affecting photosynthesis
Assimilate Sappers
piercing-sucking and rasping insects that remove plant nutrients before the plant can use it
Turgor Reducers
soil insects and stem feeders, influence plant water and nutrient balances at the root and stem sites
Fruit Feeders
Insects that injure fruit
Architecture modifiers
insects that change plant morphology to reduce yield
Crop susceptibility to injury
Relationship between injury and crop yield
Amount of damage voided
expected proportion of the population killed by a management technique
techniques to determine type and magnitude of plant response to insect injury
observation, modification of natural populations, creating artificial populations, injury simulation
Nominal thresholds
decision rules that are declared on the basis of a managers experience
Simple threshold
based on calculated EIL
Comprehensive thresholds
decision levels still under development
