FABS 222 Module 4 Lecture 4: Epidemic vs. Pandemic

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LECTURE 4: EPIDEMIC VS. PANDEMIC

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Epidemic plant disease

A plant disease outbreak where new cases occur at a rate much higher than expected within a region during a specific time period.

Pandemic plant disease

A disease outbreak that spreads across very large geographic regions such as continents or worldwide, often caused by exotic or non-native pathogens.

Difference between epidemic and pandemic

Epidemics are localized outbreaks, while pandemics spread across countries or continents and affect large plant populations.

Exotic pathogen

A non-native disease organism introduced into a new region where host plants lack resistance, increasing risk of epidemic or pandemic spread.

Plant disease resistance

The ability of a plant to prevent or reduce infection by a pathogen through genetic or induced defense mechanisms.

Durable resistance

Plant resistance that remains effective over many years despite pathogen evolution and widespread agricultural use.

Vertical resistance

Race-specific resistance controlled by one major R gene; often strong but less durable because pathogens can evolve to overcome it.

Horizontal resistance

Broad-spectrum resistance controlled by many genes; usually partial but more durable over time.

Eradicative disease control

Control strategy aimed at completely eliminating the pathogen population from an area using pesticides or resistant cultivars.

Risk of eradicative control

Strong selection pressure may lead to evolution of resistant pathogen variants.

Management disease control

Strategy that reduces pathogen population without eliminating it, lowering disease impact while limiting resistance development.

Comparison of management vs eradication

Eradication eliminates pathogens but risks resistance; management reduces disease and is often more sustainable long term.

Traditional disease management

Conventional approaches including crop rotation, sanitation, quarantine, chemical control, and agronomic practices.

Modern disease management

Advanced approaches including genetic engineering, biological control, and integrated pest management strategies.

Integrated Pest Management (IPM)

Strategy combining biological, chemical, cultural, and genetic control methods to manage pests while minimizing environmental impact.

Phytoprotection

Combined use of quarantine, chemical, cultural, biological, and genetic measures to protect crops from disease.

Quarantine in plant disease control

Regulatory practice preventing entry or spread of diseased plant material into new areas.

Legislative disease control

Government policies and regulations designed to prevent spread of plant pathogens and protect agriculture.

Inspection and certification programs

Systems ensuring plants and seeds are disease-free before transport or planting.

CFIA role in Canada

Canadian Food Inspection Agency enforces plant protection, quarantine, and food safety regulations.

PMRA role in Canada

Pest Management Regulatory Agency regulates pesticide approval, safety, and maximum residue limits.

Sanitary and Phytosanitary Agreement

WTO agreement requiring science-based plant and food safety standards for international trade.

Cultural control definition

Disease management through environmental and agricultural practice modifications.

Crop rotation

Changing crops across seasons to reduce pathogen inoculum levels in soil.

Planting date control

Selecting planting time to avoid environmental conditions favorable to pathogens.

Canopy density management

Adjusting plant spacing to reduce humidity and disease spread.

Irrigation control

Managing water to prevent disease spread favored by wet soil conditions.

Sanitation in disease control

Removal of infected plant material and sterilization of equipment to reduce pathogen survival.

Physical disease control

Use of heat, refrigeration, or solarization to kill pathogens in seeds or crops.

Chemical control

Use of pesticides such as fungicides, bactericides, or nematicides to kill plant pathogens.

Seed treatment fungicides

Chemicals applied to seeds to prevent early infection by pathogens.

Foliar fungicide application

Spraying fungicides on leaves to protect against pathogen infection.

Soil treatment fungicides

Applying chemicals to soil to control soilborne pathogens.

Protective contact fungicides

Chemicals forming a barrier on plant surfaces that prevent infection but do not cure existing disease.

Systemic fungicides

Fungicides absorbed by plants and transported through xylem to control established infections.

Fumigant pesticides

Volatile chemicals that kill pathogens in soil but may be dangerous to humans and environment.

Fungicide resistance

Genetic change in fungi that reduces sensitivity to fungicides due to repeated exposure.

Causes of fungicide resistance

Continuous use of one fungicide and failure to rotate modes of action.

Resistance management strategies

Rotate fungicides, minimize use, integrate biological control, and apply preventative treatments.

Xenobiotics definition

Synthetic chemical compounds such as pesticides that are foreign to biological ecosystems.

Pesticide persistence

Time required for pesticide degradation influenced by temperature, moisture, pH, and microbial activity.

Bioremediation

Use of microorganisms to degrade pesticides or xenobiotic compounds in the environment.

Biological control definition

Use of beneficial organisms to suppress plant pathogens.

Antibiosis in biocontrol

Antagonist produces antibiotics that inhibit pathogen growth.

Competition in biocontrol

Beneficial microbes compete with pathogens for nutrients and space.

Parasitism in biocontrol

One organism directly attacks and feeds on plant pathogens.

Mycoparasitism

A fungus parasitizes another fungus, often used as biological control against plant pathogens.