Lesson: Chemical Methods of Disease Control
Vocabulary Words and Definitions
1. Vector:
Organisms which carry and spread diseases.
2. Disinfestation::
The act of preventing the spread or harboring of diseases within an area.
3. Post harvest:
Following the harvesting of a crop.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
367.1
Notes to the Teacher
Title: Chemical/Cultural Compare and Contrast
Lesson: Chemical Methods of Plant Disease Control
Classroom Activity
Purpose:
There are many ways to control pests and diseases of plants. Some of them are cultural, others
require chemicals. In this activity, you will compare these different methods and decide which
you think is most desirable.
Activity Directions:
You will research chemical control methods for the pest which you researched in the activity for
the cultural control of plants.
Be sure to gather enough information to complete the table on the attached worksheet.
Remember to write down the books in which you found your information in case you need to
find more information about that specific aspect of your pest.
After you have found all of your information, write a one page essay on which control method
you would prefer to use. Be sure to defend your choice with specific reasons.
Material Needed:
1. Pest reference books
2. Research notes from activity 366.A
Notes to teacher:
Common Sense Pest Control, by Oklowski
Western Sunset Garden Book, Sunset Books
Model Agricultural Core Curriculum: Supplement
University of California, Davis
367.2
Name:__________________
Date:___________________
Title: Chemical/Cultural Compare and Contrast
Lesson: Chemical Methods of Plant Disease Control
Classroom Activities
Purpose:
In order to be able to control pests effectively, you must understand their life cycles. The
following activity will require you to some investigating and learning about a plant pest.
Activity Directions:
You will research chemical control methods for the pest which you researched in the activity for
the cultural control of plants.
Be sure to gather enough information to complete the table on the attached worksheet.
Remember to write down the books in which you found your information in case you need to
find more information about that specific aspect of your pest.
After you have found all of your information, write a one page essay on which control method
you would prefer to use. Be sure to defend your choice with specific reasons.
Materials Needed:
1. Pest reference books
2. Research notes from activity 366.A
Model Agricultural Core Curriculum: Supplement
University of California, Davis
367.3
Name:__________________
Date:___________________
Title: Chemical/Cultural Compare and Contrast
Lesson: Chemical Methods of Plant Disease Control
Classroom Activities Worksheet
Use the following table to record your information as you compare cultural and chemical
methods of disease control.
Disease Name:
Cultural Control
Chemical Control
Most commonly used
control method (cultural or
chemical)
Stage in Life cycle when the
pest/disease is affected by
the control
Affects of control on
surrounding areas
Cost of control
Effectiveness of control
Using the above information, write an one page essay addressing whether you would choose the
cultural or the chemical method of control for this disease.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
367.4
Name:__________________
Date:___________________
Lesson: Chemical Methods of Disease Control
Bank of Questions
1. Question:
Answer:
Name the most common method of controlling plant diseases.
The use of toxic chemical compounds.
2. Question:
Answer:
True or false? Chemicals can cure plants of diseases?
False. Chemicals prevent subsequent infestation, but they do not cure the
plants once they have been infested.
3. Question:
True or false? Dusts are usually more effective than sprays when used for
controlling plant diseases.
False. Sprays are generally more effective.
Answer:
4. Question:
Answer:
List and explain the seven ways by which plant diseases are commonly
controlled.
A. Sprays and dusts: Applied to prevent infestation of the plants. Generally,
they do not cure the plant of diseases.
B. Seed treatment: Seeds are treated with chemicals to prevent diseases from
attacking the seed and its resulting seedling.
C. Treatment of plant wounds: Wounds are treated with 20% chlorine bleach
solution or a 70% ethyl alcohol solution. They are then covered with a
dressing of 10:2: lanolin, rosin and gum, or Bordeaux paint.
D. Control of post harvest diseases: Gases and dusts such as borax, biphenyl,
thiabendazole, capstan, and benzoic acid are used to prevent storage rot.
Some of these chemicals cause the food to taste badly.
E. Soil treatment: Soils may be fumigated with gases such as chloropicrin,
ethylene dibromide (EBD), Vapam, Vorlex, and Zinophos. These
chemicals kill all life within the soil.
F. Disinfestation of warehouses: Warehouses are often cleaned and treated
with copper sulfate, or a formaldehyde solution to disinfest it.
G. Control of Insect vectors: Insect vectors are often controlled in the plants
where they winter over to reduce the likelihood of the cash crops becoming
infested with the diseases which they carry.
5. Question:
Answer:
Explain why agricultralists face a challenge when dealing with the substances
which control diseases.
A. Often times substances which kill diseases often kill or harm humans.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
367.5
B. Markets may be adversely affected if consumer's experience a scare over
the chemicals in use.
Model Agricultural Core Curriculum: Supplement
University of California, Davis
367.6