Date post: | 02-Jan-2016 |
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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
• Prevention through sanitation and insect control is much easier than treating the disease.
Diseases
• Blight• Canker• Damping off• Galls• Leaf spot• Mildew
• Mosaic• Rots• Rust• Smut• Wilt• Chlorosis
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
Chlorosis
• Normally green tissue is pale, yellow, or bleached. It results from failure of chlorophyll to develop because of infection by a virus
• Happens from fertilizer, cold weather, water, etc
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
Tobacco Mosaic & Mosiac
• 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