Presented by Dwight Scarbrough Entomologist USDA Forest Service Forest Health Protection March 19, 2013 Edition Oxford Suites, Boise, Idaho, USA Presentation Developed by James Hoffman Plant pathologist (Retired) Principles of Plant Pathology and Important Forest and Range Diseases in Idaho
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Presented by Dwight Scarbrough Entomologist USDA Forest Service Forest Health Protection March 19, 2013 Edition Oxford Suites, Boise, Idaho, USA Presentation.
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Presented by
Dwight ScarbroughEntomologist
USDA Forest ServiceForest Health Protection
March 19, 2013 EditionOxford Suites, Boise, Idaho, USA
Presentation Developed by James Hoffman Plant pathologist (Retired)
Principles of Plant Pathology and Important
Forest and Range Diseases in Idaho
Presentation Outline
Section 1: Introduction to the Basic Principles of Plant Pathology.Section 2: Important Plant Pathogens in Forest and Range Ecosystems in Idaho.
Section 3: Decline Diseases: A Complex of Biotic and Abiotic Origins.
Section 4: Hazard Trees and Your Safety.
Section 1:Introduction to the Basic
Principles of Plant Pathology
What is a Plant Disease?
A disturbance that interferes with a plant’s “normal” structure, function, or physiological processes.
As opposed to a tree injury which is caused by a single event (e.g. hatchet blow to a tree)
Disease Definitions
Parasite – an organism that lives on or in another organism.
Host – an organism that provides nutrition for an invading parasite.
Pathogen – an agent that causes disease.
Disease Triangle Disease is the product of three
interacting factors
Host Plant
EnvironmentPathogen
Disease
Signs of Diseases
• The physical presence of the pathogen on the surface or inside the plant–Fruiting bodies, fungal tissues, dwarf mistletoe shoots, etc.
–Geeks look for spores (under a microscope)
Symptoms
The expression of the host to the pathogen infection.
– Tissue death, abnormal growth forms, branch or top-dieback, lesions, yellowing, decay, defoliation, etc.
Decline diseases- (Complicated as many pathogens are involved over a long time period.)
Fungi Parasitic Plants Bacteria Mycoplasmas =
Phytoplasmas Virus Nematodes Others?
Types of Biotic Diseases (Infectious plant disease
agents)
Moisture imbalances (Drought)
Wind Temperature Nutrient and mineral
imbalances Air pollution Soil acidity or alkalinity Others?
Types of Abiotic Diseases (Non-infectious plant disease
agents)
Common Categories of Fungal Diseases
Foliage diseases
Cankers (usually stem rusts)
Decays and Rots
Root diseases
Vascular wilts
Management Techniques for Plant Diseases
Regulatory Methods Quarantines and Inspections Cultural Methods Host Eradication Rotation to Non-host Species Sanitation Altering the Environmental Conditions Biological Control Chemical Control No Control
Section 2:Important Plant Pathogens
in Forest and Range Ecosystems in Idaho
Foliage Diseases
• Needlecasts • Needle
Blights• Shoot
Blights
• Mostly caused by fungi
• Cause spotting and discoloration
• Cause premature defoliation
• May reduce growth
• Only a problem when infection occurs over consecutive years
Signs of Foliage Diseases
Signs
• Fungal fruiting bodies are often visible on the surface of infected needles
Decline diseases are caused by the interaction of a number of interchangeable, specifically ordered biotic and abiotic factors which produce a gradual general deterioration, often ending in the death of trees.
Categories of Factors That Influence Decline
Disease Predisposing Factors: Long-term, slowly changing factors which alter a trees’ ability to withstand or respond to injury-inducing agents.
Inciting Factors: Short-term physiological or biological factors that generally produce dieback of small branches.
Contributing Factors: Include a collection of environmental factors and biotic agents.
Categories of factors influencing Declines
From: Tree Disease Concepts, Paul D. Manion
Decline Disease Cycle
From:Tree Disease Concepts Paul D. Manion
Section 4:Hazard Trees and Your
Safety
Size up snag hazards in work area. Never become complacent. Always look up. Get weather reports.
Scout out parking, sleeping, work areas, and safety zones. Advise co-workers of known hazards. Face your hazard and take appropriate action. Examine work area for other hazards. Take extra caution around heavy equipment. You are ultimately responsible for your own safety.
SNAG (Hazard Tree) SAFETY:
Don’t Let This Happen To You !!
Forest & Sade Tree Pathology Website:http://www.forestpathology.org/hazard.html
FS-R1 Hazard Tree Safety Initiative – “Up the Ante” Website:http://fsweb.r1.fs.fed.us/r1_www/projects/haztree_index.shtml
Hazard Tree Information and Safety Websites
FS-R6 Field Guide for Danger Tree Identification & Response:http://www.fs.usda.gov/detail/r6/forest-grasslandhealth/insects-diseases/?cid=fsbdev2_027046FS-R6 Hazard Tree, Long Range Planning for Developed Sites: http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev2_026108.pdf