Download Plant Pathogens

PLANT PATHOLOGY:
the study of diseases in plants
PATHOGEN:
Causes of diseases:
Living factors
Non-living factors
Any disease causing agent
LIVING FACTORS ARE INFECTIOUS AND
CAN SPREAD FROM PLANT TO PLANT
These include:
fungi
bacteria
virus
insects
nematodes
rodents, birds, and other
animals
Non-living factors do not spread from plant to plant
These include:
chemicals
physical damage
Nutrient
deficiencies
In order to effectively treat a
disease it is important to know
whether the disease is infectious
or non-infectious
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)
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
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)
VOCABULARY (continued)
5) VIRUS- microscopic ; not yet classified as living or nonliving 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)
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)
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