Transcript (29.01) Diseases

Diseases
Help me! I’m dying.
Disease
• Disease is a plant disorder caused by an
infectious pathogen or agent
Groups of pathogens
• Bacteria
– Single-celled organism
– Must remain in host or
under debris
– Actively divide to spread
• Fungi
– Multi-cellular
– Eats on plants and hurts
them in the process
– Produces spores that
spread
• Viruses
– Ultramicroscopic parisites
– Attack plant tissues
– Should destroy plant
completely if found
• Parasitic plants– A plant that attaches to
another plant
– Ex. mistletoe, dodder,
lichens
Plant Disease
• Must be identified
before they can be
treated
• Warm temperatures
and moist conditions
in greenhouse plant
production make most
horticulture plant
diseases worse
Disease
• Preventing plant
disease through
sanitation and insect
control is much easier
than treating the
disease.
Diseases
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Blight
Canker sores
Damping off
Galls
Leaf spot
Mildew
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Mosaic
Rots
Rust
Smut
Wilt
Blight
• Infectious bacterium
• Cause plant to quickly
turn brown or black as if
they had been burned
• One specific blight is fire
blight-devastating apple
crops
• Prune 6-8” below
infection
Canker
• Bacterial disease
• Causes open wounds
on woody plant stems
Damping off
• Fungal disease
• Causes young plants
and seedling to rot off
at soil level
• Need clean containers
and soil and plenty of
air circulation between
plants
Galls
• Round swelling or
growths on plants
• Usually caused by an
insect that vectors the
disease
Leaf spot
• Rings of different
shades of brown,
green, or yellow
• Looks like dots or
circles
Mildew
• Fungus
• Grows on leaf surfaces
• Appears as white, gray or
purple spots
• Example is powdery
mildew
• Homemade remedy= 2 tsp
baking soda +
horticultural oil with 1 gal
water
Mosaic
• Caused by a virus
• Leaves have irregular
mottled areas with
patterns
• Ranges from dark
green to light green to
yellow to white
Rots
• Fungus
• Causes plants to decay
and die
• Usually has a unique
smell
• Improve drainage for
the plant to prevent
Rust
• Fungus
• Causes small spots on
leaves
• Resembles yellow,
orange, brown or red
rust
• Mainly on underneath
of leaf
Smut
• Black powdery disease
• Causes blisters that
burst open
• Releases black spores
• Grows on aphid’s
honeydew
Wilt
• Fungus
• Disease that blocks the
uptake of water in
plants stems
• Causes plants to look
constantly wilted even
when adequately
watered