R O C K Y M O U N T A I N C H A P T E R – I S A

2 0 1 3 C O N F E R E N C E

S E P T E M B E R 2 6

C H E Y E N N E , W Y

Part 2: Tree and Shrub Diseases

“AN IMPAIRMENT OF THE NORMAL STATE OF A PLANT

THAT INTERRUPTS OR MODIFIES ITS VITAL

FUNCTIONS”

Definition 1: Disease

The Text Includes:

• Fungi

• Bacteria

• Viruses

• Phytoplasma-like

Organisms

• Mycoplasmas

• Environmental

Factors

• Chemicals

• Critters

“ANY ENTITY THAT PRODUCES AN EFFECT OR

IS RESPONSIBLE FOR EVENTS OR RESULTS”

Definition 2: Causal Agent

Causal Agent

Causal Agent

“A LIVING ( ? V I R U S E S ? ) CAUSAL AGENT OF A DISEASE,

DISORDER OR DAMAGE…”

Definition 3: Biotic Causal Agent

Biotic Causal Agent

Biotic Causal Agent

“A NON-LIVING CAUSAL AGENT OF A DISEASE,

DISORDER OR DAMAGE…”

Definition 4: Abiotic Causal Agent

Abiotic Causal Agent: Propiconazole

Abiotic Causal Agent: Ice Damage

“PHYSICAL EVIDENCE OF THE CAUSAL AGENT.”

Definition 5: Signs

Signs

Signs

“A PLANT’S REACTION TO THE PRESENCE OR

ACTION/S OF A CAUSAL AGENT”

Definition 6: Symptoms

Symptom: Wilt

Symptom: Vascular Blockage

Symptom: Leaf Spot

Symptom: Leaf Blotch

Symptom: Chlorosis

Symptom: Die Back

Symptom: Witches Brooming

Symptom: Early Fall Color

Symptom: Blight

Symptom: Stunt

Symptom: Deformations

Symptom: Deformations

“A PLANT PATHOGEN IS A DISEASE-CAUSING ORGANISM WHICH ATTACKS PLANTS .”

Definition 7: Plant Pathogen

Plant Pathogen: Powdery Mildew

Fungal Pathogen

Plant Pathogen: Ash Yellows

Phytoplasma-like Organism

“SPREADING OR CAPABLE OF SPREADING RAPIDLY TO

OTHER HOSTS…”

Definition 8: Infectious

Infectious Diseases: Fireblight

Bacterial Pathogen

Infectious Disease: Venturia Blight on Poplar

Fungal Pathogen

Infectious Diseases: Dutch Elm Disease

Infectious Diseases: Phytophthora Canker

“DAMAGE OR LOSSES ARE ACCEPTABLE…AESTHETICALLY,

ECONOMICALLY, HEALTH-WISE”

Definition 9: Incidence

Incidence: Black Knot on Cherry

Fungal Pathogen

Incidence: Tar Spot on Maple

Fungal Pathogen

Incidence: Hackberry Mosaic Virus

Incidence: Viral Witches Broom on Hemlock & White Fir

Incidence: Phomopsis Gall on Willow & Forsythia

Incidence/Problem: Anthracnose

Fungal Pathogen

“DAMAGE OR LOSSES EXCEED ACCEPTABLE

THRESHOLDS”

Definition 10: Problem

Problem: Phytophthora Root Rot

Fungal Pathogen

Problem: Target Canker on Maple

Fungal Pathogen

Problem: Verticillium Wilt

Fungal Pathogen

Problem: Bacterial Leaf Scorch

G A R Y J O H N S O N

P R O F E S S O R / E X T E N S I O N P R O F E S S O R

U N I V E R S I T Y O F M I N N E S O T A

D E P A R T M E N T O F F O R E S T R E S O U R C E S A N D

F O R E S T R E S O U R C E S E X T E N S I O N

S A I N T P A U L , M I N N E S O T A

www.trees.umn.edu