Controlling Insects!

Controlling Insects!Controlling Insects!

InsecticidesInsecticides

Identify common insect pests and select Identify common insect pests and select an effective control method for each.an effective control method for each.Describe the six ways in which insects are Describe the six ways in which insects are killed by insecticides.killed by insecticides.List the names and characteristics of the List the names and characteristics of the three major groups of insecticides.three major groups of insecticides.Compare the six ways in which Compare the six ways in which insecticides are applied.insecticides are applied.Explain the relationship between the life Explain the relationship between the life cycle of insects and timing of application.cycle of insects and timing of application.

What is an insect?What is an insect?

InsectInsectsmall animal small animal with three defined with three defined body regions and body regions and three pairs of legs!three pairs of legs!

HEAD, THORAX, and HEAD, THORAX, and ABDOMEN!ABDOMEN!

6 Common Orders!6 Common Orders!

Orthoptera- includes the grasshopper and Orthoptera- includes the grasshopper and locustlocust

Hemiptera - includes the true bugs such as Hemiptera - includes the true bugs such as leaf hoppers and plant bugsleaf hoppers and plant bugs

Lepidoptera – moths and butterfliesLepidoptera – moths and butterflies Homoptera- aphidsHomoptera- aphids Thysanoptera- thripsThysanoptera- thrips Coleoptera- which is the largest group of the Coleoptera- which is the largest group of the

insect orders, including beetlesinsect orders, including beetles

Insect grouping!Insect grouping!

How are insects grouped?How are insects grouped?

They are grouped by the way they feed They are grouped by the way they feed on plants. So they are grouped by their on plants. So they are grouped by their mouth parts.mouth parts.

Mouth PartsMouth Parts

There are six different mouth partsThere are six different mouth parts SpongingSponging Rasping- suckingRasping- sucking SiphoningSiphoning Chewing-lappingChewing-lapping ChewingChewing Piercing- suckingPiercing- sucking

How Insecticides KillHow Insecticides Kill

Chemicals must kill insects while doing little or Chemicals must kill insects while doing little or no damage to the plant.no damage to the plant.

Stomach poisonsStomach poisonsWork against insects that eat Work against insects that eat parts of the plant.parts of the plant. Sprayed or dusted on the plantSprayed or dusted on the plant As insect eats the plant, it is poisoned through the As insect eats the plant, it is poisoned through the

stomach.stomach. Insects that chew food (caterpillars, grasshoppers, Insects that chew food (caterpillars, grasshoppers,

beetles) are controlled by stomach poisons.beetles) are controlled by stomach poisons. Example--RotenoneExample--Rotenone


Contact PoisonsContact Poisonskill insects when they kill insects when they are hit by or come in contact with the are hit by or come in contact with the poison.poison. Any type of insect can be controlled this way.Any type of insect can be controlled this way. Kill by upsetting the insect’s nervous system Kill by upsetting the insect’s nervous system

or breathing system.or breathing system. Example--malathionExample--malathion


Systemic poisonsSystemic poisonsenter the plant sap enter the plant sap and move throughout the entire plant.and move throughout the entire plant. When insect eats parts of plants or suck plant When insect eats parts of plants or suck plant

juice, chemical is swallowed.juice, chemical is swallowed. Effective with insects with chewing or sucking Effective with insects with chewing or sucking

mouthparts.mouthparts. Effective with insects that hide under leaves Effective with insects that hide under leaves

or underground.or underground. Food crops—allow time for chemical to break Food crops—allow time for chemical to break

down.down. Example--OrtheneExample--Orthene


FumigantsFumigantscontact poisons applied in contact poisons applied in gaseous form.gaseous form. Gases or fumes kill the insect after entering Gases or fumes kill the insect after entering

system through breathing pores.system through breathing pores. Insect must absorb the poison for this Insect must absorb the poison for this

insecticide to be effective.insecticide to be effective. Used to control soil-borne insects that Used to control soil-borne insects that

damage roots.damage roots. ExampleExampleTAMETAME


RepellantsRepellantsdo not kill insects, but drive do not kill insects, but drive them away before they attack the plant.them away before they attack the plant. ExampleExamplealuminum foil (repels flying insects)aluminum foil (repels flying insects)


Attractants and PhermonesAttractants and Phermoneswork in the work in the opposite way from repellants.opposite way from repellants. They lure insects to their death.They lure insects to their death.

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Chemical Makeup of InsecticidesChemical Makeup of Insecticides

Three groups!Three groups!

Inorganic CompoundsInorganic Compounds

Organic CompoundsOrganic Compounds

Synthetic Organic CompoundsSynthetic Organic Compounds

Inorganic CompoundsInorganic Compounds

Mineral originMineral origina mineral is used as the a mineral is used as the basis for the poisonbasis for the poison

Usually work in the form of a stomach Usually work in the form of a stomach poison.poison.

Example—SulfurExample—Sulfur

Organic CompoundsOrganic Compounds

Derived from plantsDerived from plants

Work in form of stomach or contact Work in form of stomach or contact poisonspoisons

Example—rotenone and pyrethrumExample—rotenone and pyrethrum


Recent origin (last 30-35 years)Recent origin (last 30-35 years)

Produced in the laboratoryProduced in the laboratory

Many are also toxic to humans.Many are also toxic to humans.

Three GroupsThree Groups Chlorinated HydrocarbonsChlorinated Hydrocarbons OrganophosphatesOrganophosphates CarbamatesCarbamates


Chlorinated HydrocarbonsChlorinated HydrocarbonsLong Long RESIDUAL Control (continue to kill long RESIDUAL Control (continue to kill long after application)after application)

ExampleExampleDDT (not used in US)DDT (not used in US)


OrganophosphatesOrganophosphatesContains chemicals Contains chemicals most toxic to warm-blooded animalsmost toxic to warm-blooded animals

Absorbed rapidly through the skinAbsorbed rapidly through the skin

ParathionParathionone drop in the eye can kill a one drop in the eye can kill a human being.human being.

ExampleExampleMalathion (relatively safe)Malathion (relatively safe)


CarbamatesCarbamatessafest insecticides on the safest insecticides on the marketmarket

Break down rapidly (2-7 days) and leave Break down rapidly (2-7 days) and leave no residue to contaminate the environmentno residue to contaminate the environment

Do not build up in the bodies of warm-Do not build up in the bodies of warm-blooded animalsblooded animals

Example—SevinExample—Sevin

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Controlling Insects!