Horticulture Science Lesson 32 Determining the Kinds of Pesticides

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Horticulture Science Lesson 32Determining the
Kinds of Pesticides
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Interest Approach
Ask the students, If given a choice, would you
prefer eating an apple or other produce that
displays insect damage over damage-free produce?
Tell them that most Americans reject produce that
has evidence of insect damage. Ask if they feel
the same about potted flowering plants, cut
flowers, or bedding plants they might buy. Once
it has been established that pest control is
important, present the objectives of the lesson.
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Student Learning Objectives

• Identify the major classifications of pesticides.
• Describe the major classifications of herbicides.
• Explain the major classifications of insecticides.

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Terms

• contact herbicide
• contact insecticide
• fumigant
• fungicides
• herbicides
• insect
• insecticides
• miticides

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Terms

• mode of action
• molluscicides
• nematocides
• nematodes
• nonselective herbicide
• pesticide

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Terms

• postemergence applications
• preemergence applications
• preplanting applications
• respiratory insecticide
• rodenticides
• selective herbicide
• stomach insecticide
• systemic herbicide

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What are the major classifications of pesticides?

• Pesticides are the materials used to control
  pests.
• These chemicals may be natural or man-made.
• Although once used almost exclusively, is now
  viewed as only one component of an IPM program.
• In fact, use of chemical pesticides is now often
  done only when absolutely necessary.
• Application of pesticides must be done safely to
  reduce potential injury to people and the
  environment.

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What are the major classifications of pesticides?

• Insecticides are used to control insects, which
  are a group of animals with an exoskeleton and
  three body parts.
• Most insects have six legs and four wings.
• Insects are killed by body contact with the
  chemical, by swallowing the insecticide, or by
  insecticides that enter through the respiratory
  system.

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What are the major classifications of pesticides?

• Miticides are used to control mites and ticks.
• They are usually killed by coming in contact with
  the chemical.

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What are the major classifications of pesticides?

• Fungicides are used to control fungal disease.
• Fungicides are used to prevent a plant from
  becoming infected.
• Therefore, they are applied before the disease is
  present.

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What are the major classifications of pesticides?

• Herbicides are used to kill unwanted plants.
• Rodenticides kill rodents, such as rats and mice.
  
• These chemicals are usually applied as bait.
• Eating the chemical poisons the rodents.

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What are the major classifications of pesticides?

• Nematocides kill nematodes, which are tiny
  hair-like roundworms that feed on the roots of
  plants.
• Nematocides are usually applied in the form of a
  fumigant, which is a substance that produces a
  smoke, vapor, or gas when applied.

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What are the major classifications of pesticides?

• Molluscicides are used to kill slugs and snails.
• These chemicals are usually applied as bait,
  which attracts the slugs and snails and poisons
  them.

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What are the major classifications of herbicides?

• Herbicides are classified by selectivity, contact
  versus translocation, timing, and mode of action.
• Herbicides are classified as being selective or
  nonselective.
• Selective herbicides act on certain plant species
  and not others.
• Nonselective herbicides kill all vegetation.

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What are the major classifications of herbicides?

• Herbicides may act on contact with plants or be
  translocated in the plant.
• Contact herbicides kill the parts of a plant to
  which it is applied.
• Translocated or systemic herbicides are absorbed
  by the roots or other plant parts and moved
  throughout the plant by vascular tissues.
• Translocated herbicides are particularly
  effective with perennial plants.

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What are the major classifications of herbicides?

• Timing refers to the stage of the crop or weed
  development.
• Preplanting applications are made before the crop
  is planted to control annual weeds.
• Preemergence applications are made before the
  crop or weeds emerge.
• Postemergence applications are completed after
  the crop or weeds have emerged.

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What are the major classifications of herbicides?

• Mode of action refers to how herbicides kill
  weeds.
• The mode of action is the effect on metabolic
  processes or enzyme systems that result in a
  lethal or toxic action in the plant.
• Herbicides may have a single mode of action or a
  multiple mode of action.

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What are the major classifications of
insecticides?

• Insecticides are classified by how they enter an
  insects body.
• Three general groups of insecticides are contact,
  stomach, and respiratory.

• Contact insecticide is absorbed through the skin
  or exterior of an insect.
• The chemical must be applied directly on the
  insect and is normally used with sucking insects.

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What are the major classifications of
insecticides?

• Stomach insecticide is effective when eaten.
• The chemical is applied to the plant parts, which
  are eaten by the insect.
• This type of insecticide is most effective on
  chewing insects.
• Respiratory insecticide is an insecticide that
  enters the respiratory system of the insect.
• It is commonly called a fumigant.
• This type of insecticide is used in enclosed
  places.

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Review/Summary

• What are the major classifications of pesticides?
• What are the major classifications of herbicides?
• What are the major classifications of
  insecticides?