This document discusses various methods for applying chemicals to control plant diseases. It describes aerial spraying, foliar spraying, preventative and curative spraying, seed treatment, soil drenching, trunk injection, chemigation, fumigation, chemical rotation, localized and systemic treatment, and specific inoculation methods like leaf spray inoculation, needle inoculation, soil drenching, root dip, and grafting. The goal of these application methods is to effectively deliver chemicals to pathogens affecting different plant parts and manage diseases.

1. PLPT 6315
PLANT DISEASE
MANGAGEMENT
PRESENTED BY: GROUP 1

3. Introduction
• Chemical compounds, known as fungicides, nematicides, viricides or
herbicides are commonly used to control plant diseases in field,
greenhouse and storage.
• Chemicals either inhibit the germination or lethal to pathogen.
• Most chemicals applied to fruit with 25% to vegetables.
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4. • Chemicals are used to disinfest seeds, tubers, and bulbs and protect
stored fruits and vegetables from infection.
• Older chemicals were confined to the plant area and could not stop to
cure diseases after that started.
• Newer chemicals have therapeutic action and are absorbed and
translocated systemically by plants.
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5. METHODS AND
APPLICATION OF
CHEMICALS FOR PLANT
DISEASE CONTROL

6. AERIAL SPRAYS
Aerial spraying involves applying chemicals from aircraft.
This method is suitable for large-scale agriculture where extensive fields
or orchards need treatment
It ensures even coverage of the crop and is particularly efficient for
disease control in expansive areas.
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7. FOLIAR
SPRAYS
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Foliar spraying involves applying
chemical solutions directly onto the
leaves of plants. This method is effective
for controlling diseases that primarily
affect the above-ground parts of the
plant, such as leaf spots or powdery
mildew. It allows for direct contact with
the target pathogens and is often
employed using handheld sprayers or
mechanized equipment.

8. PREVENTIVE AND CURATIVE SPRAYS
• PREVENTIVE SPRAYS
• Applying fungicides or
bactericides before the onset
of disease helps create a
protective barrier on plant
surfaces. This method is
proactive and aims to prevent
infections from occurring.
• CURATIVE SPRAYS
• When symptoms of disease
are already visible, curative
sprays involve applying
chemicals to slow down or
stop the progression of the
infection. This is a reactive
approach to manage
established diseases.
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9. Treating seeds with fungicides
before planting helps protect
emerging seedlings from soil-
borne pathogens. This method
is particularly important for
crops vulnerable during
germination.
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SEED TREATMENT

10. SOIL
DRENCHES
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Soil drenching entails pouring or
injecting chemical solutions into the
soil around the plant's root zone.
This method is especially useful for
controlling soil-borne diseases. The
chemicals penetrate the soil and
come into contact with the
pathogens present, providing
localized treatment to the root
system.

11. TRUNK
INJECTION
Trunk injection is a method where
chemicals are injected directly into
the trunk of trees. This is particularly
useful for diseases that affect the
vascular system. The injected
chemicals travel upward, reaching
various parts of the tree and
providing targeted treatment.
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12. CHEMIGATION
Chemigation involves introducing chemicals into irrigation systems. This
method ensures uniform distribution of chemicals throughout the crop,
utilizing existing irrigation infrastructure for disease control.
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13. FUMIGATION
• Fumigation is the application of chemicals in gaseous form. This
method is often employed in enclosed spaces like greenhouses or soil
beds. Fumigants can penetrate the soil and eliminate soil-borne
pathogens, providing a thorough and efficient means of disease
control.
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14. CHEMICAL ROTATION AND
MIXTURES
Alternating different chemicals or using mixtures can be part of a strategy
to prevent the development of resistance in plant pathogens. This involves
rotating or combining fungicides with different modes of action.
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15. MODE OF TREATMENT
• LOCALIZED TREATMENT
• Applying chemicals
specifically to areas showing
disease symptoms or high
pathogen concentrations can
help manage disease in
localized areas without
widespread use.
• SYSTEMIC TREATMENT
• Using systemic fungicides
allows plants to absorb the
chemicals, providing internal
protection. These chemicals
move within the plant, offering
defense against a broad
spectrum of diseases.
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16. SPECIFIC INOCULATION
METHODS

17. LEAF SPRAY
INOCULATION
Spraying a suspension of
pathogen spores or cells directly
onto plant leaves. This method
mimics natural infection
through airborne spores and is
commonly used for foliar
pathogens
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18. NEEDLE
INOCULAT
ION
Using a fine needle to deliver
pathogen spores or cells directly
into plant tissues, often leaves
or stems. This method provides
a controlled way to introduce
pathogens at specific locations.
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19. SOIL
DRENCHING
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Applying a suspension of
pathogen spores or cells to
the soil around the plant's
root zone. This method is
suitable for soil-borne
pathogens and allows for the
initiation of root infections.

20. ROOT DIP
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Immersing plant roots in a
solution containing pathogen
spores or cells. This method
is used to establish infections
in the root system

21. GRAFTING
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Joining plant tissues
together, often by grafting
an infected scion onto a
healthy rootstock. This
method allows the transfer
of pathogens between plant
parts.