diseases
Post on 02-Jan-2016
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Disease• Disease is a plant disorder caused by an
infectious pathogen or agent
Host – Plant the disease attacksPathogen – Any disease causing agentEnvironment – moisture and temperature needed for the pathogen to grow
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
• Blight• Canker sores• Damping off• Galls• Leaf spot• Mildew
• 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
• Tomato mosaic virus is common in tomatoes
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
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