1. the study of diseases in plants
PLANT PATHOLOGY:
the study of diseases in plants
PATHOGEN:
Any disease causing agent
Causes of diseases:
Living factors
Non-living factors

2. LIVING FACTORS ARE INFECTIOUS AND CAN SPREAD FROM PLANT TO PLANT
These include:
fungi
bacteria
virus
insects
nematodes
rodents, birds, and other animals

3. Non-living factors do not spread from plant to plant
These include:
chemicals
physical damage
Nutrient deficiencies

4. In order to effectively treat a disease it is important to know whether the disease is infectious or non-infectious

5. FOR DISEASES CAUSED BY LIVING PATHOGENS TO OCCUR THREE CONDITIONS MUST BE MET
1. There must be a susceptible host plant
2. The pathogen must be present (even
though it might not be seen)
3. The environment must be suitable for
the pathogen to grow and thrive
(temperature and humidity are
important factors)

6. IF THERE IS NO PATHOGEN PRESENT THERE CANNOT BE A DISEASE!!!!
when a disease seems to come from
nowhere, it was just hiding until the
conditions became perfect for it to
grow and spread- remember, most
pathogens are microscopic

7. VOCABULARY TERMS: 1) BIOTIC- living 2) ABIOTIC- non-living
3) FUNGUS- a living organism with no chlorophyll that reproduces by spores, not seeds. (examples: molds, yeasts, mushrooms (effects: leaf spot; fruit rot; stem rot;
root rot)
4) BACTERIA- a one celled living organism. Bacteria
have no cell wall and no chlorophyll
(effects: leaf spot; fruit rot; stem rot;
root rot)

8. VOCABULARY (continued)
5) VIRUS- microscopic ; not yet classified as living or non-
living because viruses cannot survive on their
own without a healthy host cell; viruses have an
outer covering made of protein (effects: causes
distorted, and/or stunted, and/or discolored growth
6) VIROID- viroids are smaller than viruses and do
not have the outer protein covering
(effects: same as viruses)
7) NEMATODE- a microscopic roundworm that
usually lives in the soil and
feeds on the roots of a plant
(effects: stunted growth; distorted
roots)

9. VOCABULARY (continued)
PARASITIC SEED PLANT- a true plant
with chlorophyll that attaches to a
host plant and steals the nutrients
from the host plant (effects: causes a
general weakening of the host plant)

10. REMEMBER:
MOST DISEASE THRIVE IN DAMP MOIST ENVIRONMENTS. AVOID OVERWATERING PLANTS AND TRY NOT TO CREATE PUDDLES IN THE GREENHOUSE
THROW GARBAGE (soil, dead leaves, dead plants, etc.) in COMPOST or DUMPSTER- DO NOT THROW ON FLOOR OR LEAVE ON BENCHES
PUT EMPTY USED POTS OUTSIDE