DS - Insecticides I

Question 1

What is the definition of a pesticide?

Answer 1

Any substance or mixture intended for preventing, destroying, repelling, or mitigating any pest

Question 2

What are some types of pesticides? (5)

Answer 2

• Insecticides
• Nematicides
• Rodenticides
• Herbicides
• Fungicides

Question 3

What is a pest?

Answer 3

Any species that has a harmful effect on humans, their food, or their living conditions

• A destructive species that attacks crops, food, livestock etc.
• Threaten human health, comfort or welfare

Question 4

Why do we need insecticides?

Answer 4

Insecticides improve crop yields

Question 5

Why is it important to understand insecticide modes of action? (4)

Answer 5

• Safety – proper use of toxins
• Protect beneficial insects (e.g., pollinators)
• Resistance management
• Design selectively toxic compounds for specific pests

Question 6

What is the classic characteristic of a pest species?

Answer 6

• The classic pest is an r species (high growth rate, many offspring)
• But some can be k species (low growth rate, few offspring) and they usually have escaped control by natural enemies because of introduction

Question 7

What are the 5 common causes of pest outbreaks?

Answer 7

• Environmental change
• Introduction from abroad
• Destruction of natural enemies
• Development of resistance
• Higher quality standards

Question 8

What agricultural factors can lead to pest outbreaks in crops? (6)

Answer 8

• Monocultures
• High-yielding crops (nutritious)
• Removal of natural enemies
• Continuous food resource (intensification)
• Accelerated movement of plants and pests
• Reliance on chemicals

Question 9

What is the difference between injury and damage caused by pests?

Answer 9

• Injury: Physical harm caused by pests (e.g., consuming leaves)
• Damage: Monetary loss due to injury (e.g., reduction in yield)

Question 10

What is the Economic Injury Level (EIL) in pest control?

Answer 10

The pest density at which there is greatest difference between the cost and the benefit of pest control

Question 11

What 2 pieces of economic information are required to determine if injury has exceeded EIL?

Answer 11

How much financial loss is the pest causing?

How much will it cost to control the pest?

Question 12

Below the EIL vs Above the EIL

Answer 12

• Below the economic injury level, it is not cost-effective to control the pest population because the cost of treatment (labour plus materials) would exceed the amount of damage.
• Above the economic injury level, however, the cost of control is compensated by an equal or greater reduction in damage by the pest.

Question 13

What are the main stakeholders in pest management? (5)

Answer 13

• Governments and funding agencies
• Research scientists
• Commercial companies
• Farmers and growers
• Customers and consumers

Question 14

What are some types of insecticides and methods of application? (12)

Answer 14

• Solutions
• Wettable powders
• Emulsifiable concentrations
• Suspensible concentrates/flowables
• Water-soluble powders
• Dusts
• Baits
• Granules
• Water dispersible granules
• Ultra-low volume formulations
• Aerosols
• Controlled-release formulations

Question 15

What is an insecticide formulation?

Answer 15

Mixing of the active ingredient (AI) with inert ingredients for application

Question 16

How do insecticides enter an insect’s body? (3)

Answer 16

1) Through the cuticle (lipophilic and hydrophilic phases)

• Carbaryl penetrates through cuticle of insect species at different rates

2) Gas exchange via spiracles and trachea

3) Ingestion of systemic insecticides

Question 17

How are systemic insecticides typically applied?

Answer 17

Applied to seeds and dispersed throughout the plant