Diseases & Viruses Objective: Discuss diseases and viruses.

Diseases

Plant disorders caused by an infectious pathogen or agent

3 conditions necessary for diseases in plants: Host plant is the plant the

disease attacks Disease causing organism or

pathogen must be present A favorable environment for

disease organism to develop (warm & moist)

Diseases

Using the sources in the room define the following terms related to plant diseases: Pathogen Fungi Bacteria Virus

Bacteria

Bacteria are single celled microorganisms

Bacterial Leaf Spot

Rings of different shades of brown,

green or yellow spots on leaves

Bacterial Blight

Causes plant to quickly turn brown or black as if they had

been burned

Bacteria

Consider a tomato…look up one Bacteria found in the tomato plant.

Fill in the chart provided.

Fungi

Fungi cannot make their own food They develop hyphae, structures

that grow & absorb nutrients from the host plant

Many fungi spread by spores Fungi diseases:

Damping off Rust Powdery mildew Galls

Look up these common Fungi diseases! You have 10 minutes!

Fungi

Damping Off

Rust Powdery Mildew

Galls

Causes young plants and seedlings to rot off at the soil level

Cause small spots on the leaves that resemble yellow, orange, brown or red rust mainly on the underside of leaves

Grows on the upper & lower leaf surface as white or gray powdery substance. Common in houseplants.

Round swellings or growths usually on tree branches or leaves.

Fungi

Consider a tomato…look up one Fungus found in the tomato plant.

Fill in the chart provided.

Viruses

Pathogens with an extremely narrow host range and are usually a threat to crops Tobacco Mosaic

Virus• Attacks tomatoes, peppers, poinsettias & tobacco

• Can be transferred by hands of a smoker

• Wash hands before working with plants to control the spread of this virus

• Causes irregular mottled areas with patterns ranging from dark to light green and yellow to white

Virus

Consider a tomato…look up one Virus found in the tomato plant.

Fill in the chart provided.

Diseases & Viruses in the Industry

Horticultural disease and viruses can dramatically impact the plant industry

Find a Current Event that dealing with a plant’s disease or virus

Be sure to specifically state the disease/virus and how it causes damage to the host

Summarize the Current Event in a half page (minimum)

Site your sources