Common Plant
Diseases
Practice Teacher
Plant Disease
Plant disease is an impairment of
the normal state of a plant interrupts or
modifies its vital functions. All species of
plants, wild and cultivated alike, are
subject to disease.
Many valuable crop and ornamental plants
are very susceptible to disease and would have
difficulty surviving in nature without human
intervention.
Common plant diseases example:
a bacterial plant disease characterized
by spotting of the affected parts or the most
destructive leaf disease of capsicum.
Bacterial spot is caused by the following:
• Warm and Wet environment
• Negative bacteria
and it looks like:
• Small
• Dark
• Raised spots
a fungal infection where you eventually
see the offending fungus, not just the
symptoms of the underlying disease.
Symptoms include:
Brown spots on leaves and buds
a bacterial disease caused by
Pseudomonas
syringae
pv.
lachrymans.
a are very small insects which
are really difficult to see with the
naked eyes.
Spider mites are really harmful to the
crop. Mostly, they exist under the leaves and
form a web there. As spider mites are really
small and invisible to the eyesight so your
slight carelessness leads to the extensive
damage of the crop. After the attack of spider
mites, your crop stops thriving and turned into
yellowish color.
What you can do to stop the spread of
infection?
Remove infected plants and apply a fungicide.
Some method to control plant disease:
• Site Selection
• Apply Fertilizer
•Crop rotation
Continues plantings of vegetables within the same plant
family provide opportunities for pathogen buildup. Do not plant
the same family of vegetable in the same areas year after year.
In general, a plant becomes diseased when it
is continuously disturbed by some causal agent
that results in an abnormal physiological process
that disrupts the plant’s normal structure, growth,
function, or other activities.
Activity
Directions: Make an essay of each picture below of
what you have observe. 5 points each (1/2 crosswise)
Assessment
Direction: Match column A and B.
1.
Angular Leaf Spot
Bacterial Spot
2.
3.
Spider Mite
4.
Botrytis Blight
Find any kind of plant leaves that has sign and
symptoms of disease from your surrounding.
Paste the plant leaves on 1 whole sheet of paper
and write what you have observed.