1. “SEMINAR ON PLANT PATHOLOGY”
Plant Pathology
Plant pathology (also phytopathology) is the scientific study of plant diseases caused by and
environmental conditions. QUESTION: FATIMA – What is pathogen? QUESTION: What organism that cause
infectious disease ? Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids,
virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites
like insects, mites, vertebrate, or other pests that affect plant health by consumption of plant tissues. ADDITIONAL
INFORMATION - Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles,
economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals,
pathosystem genetics, and management of plant diseases.
Brief History
Like human beings and other animals, plants are subject to diseases. In order to maintain a sufficient food
supply for the world's population, it is necessary for those involved in plant growth and management to find ways to
combat plant diseases that are capable of destroying crops on a large scale. IF THE PLANTS HAVE INFECTIOUS
DISEASE WHAT WOULD HAPPEN ? However the use of pesticides, fungicides, herbicides, fertilizer and other
chemicals to control plant diseases and increase crop yields, also poses significant environmental risks air,
water and soil can become saturated with chemical that can be harmful to human and ecosystem health.
2 Causes of Plant diseases WHAT ARE THE TWO CAUSES NG PLANT DISEASE ?
1. Pathogens
2. Environmental conditions OR PHYSIOLOGICAL FACTORS
is therefore an increasingly important branch of applied science.
Symptoms of Plant Diseases
1. Colour change - change of colour from the normal. SA HAYOP CAMOUFLAGE SA TAO PG MY HEPA. QUESTION
ANO PA UNG NGCHANGE NG COLOR ? ANIMAL TAO
2. Hypoplasia - Inhibition of growth resulting in stunting or dwarfing. SA TAO NGYA2RI TAYO ! QUESTIONGIANTISM
3. Blight Burnt appearance SA TAO PAGNABU2LOK SA KATAWAN .
4. Leaf Spots - Fungal leaf spots - spots usually vary in size. Generally are round and occasionally elongate on stems.
Zones of different color or texture may develop giving the spot a "bull's eye" effect. Spots are not limited by leaf veins.
Bacterial leaf spots - spots are often angular due to limitation by leaf veins. Color is usually uniform and no signs of
plant pathogen are evident. Tissue may appear initially as being water soaked but may become papery as it dries.
5. Wilts - Wilts are characterized by a general loss of turgidity of leaves or possibly entire plants due to the loss of water.
The loss is most often caused by a blocking of the water flow through the xylem. This blockage can be caused by the
presence of various bacteria. PG LOSS OF TURGIDITY NG LEAVES ANONG POCBLE N MANGYARE ?
General Control Measures of Plant Diseases:
Physical Control Methods
1. Quarantine regulations - Entry of diseased plants should be prevented. MY A AT B
2. Field sanitation - To destroy completely or partially the source of infection present in the soil. This is done by
a) Removal of diseased plant debris and their burning.
b) Use of chemical.
c) Crop rotation.
d) Proper spacing between plants
e) Mixed cropping