Cprt 4.3 - Economic concept of pest control

Question 1

The economic concept of pest control was first applied to ____ such that it is almost equated to the economics of controlling insect pests

Answer 1

insects

Question 2

The scientific study of pest and pest control strategies that recognize the financial impact insects have on the industry, agriculture, and human society in general.

Answer 2

economic entomology

Question 3

The monetary value lost to the commodity due to injury by the pest

Answer 3

damage

Question 4

Defined as the physical harm or destruction to a valued commodity caused by the presence or activities of a pest

Answer 4

injury

Question 5

True or False

spoilage, reduction in yield, loss of quality are considered as injury

Answer 5

False

They are considered as damage

Question 6

True or False

Any level of pest infestation causes injury, but not all levels of injury cause damage.

Answer 6

True

Question 7

Occurs whenever the value of “A” is greater than the value of “B.”

Answer 7

Pest Outbreak

Question 8

True or False

Estimates of damage are often based on actual or expected loss rather than potential loss

Answer 8

False

Estimates of damage are based on potential loss

Question 9

True or False

Actual losses are relatively easy to measure in agricultural or industrial settings but losses from household insects, vectors of human disease, and nuisance pests can be much harder to quantify.

Answer 9

True

Question 10

The ____, where “A” = “B”, is known as the ____

Answer 10

break-even point ; economic injury level

Question 11

The population density at which the cost to control the pest equals the amount of damage it inflicts (actual or potential).

Answer 11

Economic injury level

Question 12

EIL can be mathematically expressed as?

Answer 12

EIL = CxN/VxI

Question 13

Occasionally, when the insects themselves are difficult to count or detect, EIL may be based on?

Answer 13

measurement of injury

Question 14

The economic injury level is usually expressed as

Answer 14

number of insects per unit area or sampling unit

Question 15

A point below the economic injury level at which a decision is made to apply a treatment for the pest

Answer 15

Economic threshold level

Question 16

True or False

ETL is sometimes called the “economic threshold” because it is the decision point for action.

Answer 16

False

ETL is called “action threshold”

Question 17

Defined as the pest density at which steps are first taken to ensure that a potential pest population never exceeds its economic injury level.

Answer 17

Economic Threshold Level

Question 18

The economic threshold is usually expressed in?

Answer 18

insect density units or terms of an injury measurement

Question 19

True or False

The economic threshold is always lower than the economic injury level to allow for sufficient time to enact control measures and prevent further inury to the crop

Answer 19

True

Question 20

Data needed to determine EIL and ETL

Answer 20

1. Pest Density
2. Amount of Damage (monetary value of the lost yield)
3. Yield Data
4. Cost of the lost yield = amount of damage
5. Cost of control

Question 21

In plant diseases, the extent of pest level can be assessed using the ____ or % ____ for plant diseases

Answer 21

disease incidence ; disease severity

Question 22

Used for measuring diseases that affect whole plants

Answer 22

Disease incidence

Question 22

In case of localized infection injury is expressed as?

Answer 22

Disease severity

Question 23

Disease incidence is expressed as?

Answer 23

% infection

Question 24

Disease severity is expressed as?

Answer 24

% leaf area infected

Question 25

Can be the percent of leaves infected for the whole plant or the percentage of leaf area infected (showing the lesion)per diseased plant

Answer 25

Disease severity

Question 26

Disease incidence formula

Answer 26

% infection = No. of infected plants/Total no. of plants x 100

Question 27

ETL of stem borer

Answer 27

• moderate to severe in a nursery
• 5% dead hearts or one egg mass/m2 at planting to tillering stages or more moth/m2

Question 28

ETL of rice whorl maggots

Answer 28

20% damage hills up to 30 days after planting

Question 29

ETL of brown planthopper

Answer 29

• 5-10 insects per hill at tillering stage
• 20 insects per hill, 5-10 insects at flowering stage

Question 30

Signs of brown planthopper damage

Answer 30

• hopper burn
• rice rugged stunt virus