Chemical Control: Insecticides

1
Chemical ControlInsecticides
2
Insecticides are one of the four building blocks
of IPM
IPM
Chemical
Biological
Plant resistance
Cultural
3
Component of pest control since the 1950s
4
Not a perfect solution

• At least 3 million workers poisoned each year
• 20 000 deaths per year
• Teratogenic, carcinogenic and mutagenic effects

5
Public concern about Insecticide use
100 of us have some insecticide residue in our
bodies
6
Insecticides represent an 8 billion industry
7
For the Correct use of insecticides, we need to
consider
Ease of use
Insecticide resistance
Economics
Safety
Insect behavior
Way of delivery
Ecotoxicological impact
Toxicology
8
When to apply?

• Thresholds
• Calendar applications

9
Problems with calendar application approach

• Resistance
• Secondary pests
• Destruction of natural enemies
• Health hazards
• Environmental hazards

10
Going towards better insecticide use
(Dent 2000)
11
Insecticide Composition
Insecticide Active Ingredient Additives
12
Classes of Insecticides

• Botanical Insecticides
• Sabadilla
• Nicotine
• Quassia
• Unsaturated isobutylamides
• Ryanodine
• Naphtoquinones
• Rotenone
• Sweet flag
• Marigolds
• Pyrethrum
• Azadirachtin
• Essential oils
• Botanical insecticides

• Synthetic Insecticides
• Organochlorines
• Organophosphates
• Carbamates
• Pyrethroids
• Neonicotinoids

• Biorational Formulations
• Growth regulators
• Pheromones
• Microbial formulations

13
Botanical Insecticides

• Secondary compounds
• Alkaloids
• Terpenoids
• Phenolics
• Glucosinolates
• Etc.

14
(No Transcript)
15
(No Transcript)
16
Reasons for lack of Commercial Development

• Perceived as old fashioned
• Lack of representation on official lists
• Not as dramatic effects as synthetic insecticides
• Inactivation by exposure to air and light
• Problems due to seasonal availability
• Lack of quantitative information regarding
  dosages
• Lack of quantitative information regarding
  toxicity

17
Synthetic Insecticides

• Synthetic Insecticides
• Organochlorines
• Organophosphates
• Carbamates
• Pyrethroids
• Neonicotinoids

18

• Affect synaptic transmission

19
Concerns

• Some are highly persistent in the environment
• They accumulate in the food chain
• If release from fats, poisoning or death
• Some are banned in developed countries
• Unfortunately, still used in some developing
  countries

20
Examples
Carbamates
Organochlorines
- Aldicarb -Carbofuran

• - DDT -
  Endosulfan
• - Aldrin - Gamma
  HCH
• - Dieldrin - Gamma
  BHC

Pyrethroids

• -Tefluthrin
• - Deltamethrin
• - Lambda
• -cyhalothrin
• - Permethrin
• - Cypermethrin

Organophosphates
-Diazinon -Fenitrothion -Dichlorvos
-Dimethoate - Malathion

• -imidacloprid
• -nitempyram
• - acetamiprid
• - thiamethoxam

Neonicotenoids
21
Biorational Formulations
22
Growth Regulators

• Interfere with development
• Disrupt metamorphosis and reproduction
• Specific for arthropods

23
Hormones involved

• Moulting hormones or ecdysones
• - Re-absorption of old cuticle
• - Deposition, hardening and tanning of new
  cuticle
• Juvenile hormones
• - Prevent insect from going to next instar.

24

25
Concerns

• Take longer to act than conventional insecticides
• Ecdysones are expensive
• Not ideal when larval stages are the pest

26
Examples
Juvenile Hormones
Chitin Synthesis Inhibitors

• - Methoprene
• - Tebufenozide
• - Fenoxycarb
• - Pyriproxifen

- Diflubenzuron - Hexaflumuron - Triflumuron
Triazine Derivatives
- Melamine - Cryomazine
27
Pheromones

• Mediate intraspecific interactions
• Around 50 available for IPM
• Mostly use in association with traps

28
Pheromones Uses in IPM

• Monitor pest populations
• Mass trapping
• Mating Disruption
• Lure and Kill

29
Microbial Formulations

• Uses bacteria, fungi, nematodes, protozoa and
  viruses
• Mostly used as inundative releases
• Specific for arthropods

30
Increase interest in Microbial Pest Control

• Resistance to synthetic insecticides
• Decrease in discovery of new synthetic
  insecticides and increase of discovery of
  microbial novel agents
• Increase in the perception of risk posed by
  synthetic insecticides
• The high host-specificity of microbial pesticides
• Improvements in the production and formulation of
  microbial pesticides
• Relaxation of the regulations governing
  registration of microbial pesticides

31
The Pesticide Treadmill

• Pest resurgence
• Secondary pest outbreaks
• Pesticide resistance

32
Going towards better insecticide use
(Dent 2000)
33
Insecticide Composition
Insecticide Active Ingredient Additives