Lecture 1 Flashcards
Define Plant Pathology:
Plant Pathology is the study of:
- living entities and environmental conditions that cause disease in plants
- mechanisms by which these factors result in disease
- interactions between disease agents and hosts
- disease prevention and management
What occured in 1845-1846?
Irish Potato Famine
Who is the father of plant pathology?
What did he do?
Anton deBary
- In controlled experiments, proved that a fungus causes late blight (1861)
What did the Irish Potato Famine introduce?
- The political aspects of the food supply
- Risks of genetic uniformity in crops
- Problems when new crops are distributed throughout the world
Define Plant Disease:
- a condition of abnormal physiology in a
susceptible host plant that is a result of
the plants constant association with a
disease causing agent within a set of
favorable environmental conditions.
Name all aspects of the disease triangle.
Name the 2 types of disease causal agents:
- Biotic (infectious)
- Abiotic (non-infectious)
Explain Biotic as a causal disease agent:
. **Biotic (infectious) **
- organism (pathogen) grows, multiplies, and spreads to other plants
- 10% of diseases reported
Explain Abiotic as a causal disease agent:
- environmental conditions that impact
plant development (physiogens) - much more common: 90% of diseases
reported (injury not disease)
Explain Abiotic Causal Agents (physiogens):
• **Physical factors **
- temperature
- moisture
• Chemical factors
- air pollutants
- pesticides
- fertilizers and salts
• Mechanical factors
- everything else
Explain Biotic Causal Agents (pathogens):
• Fungi (largest group of plant pathogens)
• Prokaryotes (no nuclear membrane)
– bacteria
– mollicutes (phytoplasmas, spiroplasmas)
• Nematodes (round worms)
• Viruses (nucleic acid with a protein coat)
• Viroids (naked RNA with no protein coat)
• Parasitic plants
• Algae
• Protozoa
• Insects and mites
What is Mycology?
The study of Fungi
What is the most common (important) of the plant pathogens? explain.
Fungi
• Most important as agents of decay
• Can attack wood products, leather goods, fabrics,
petroleum products, foodstuffs
- Infects animals and plants
Explain Bacteria:
• 1600 species are known, most are saprophytic *(obtains its nutrtion from assimilating organic matter) *
• Important as decomposers and in nitrogen recycling
• Cause human, animal (e.g., tuberculosis, pneumonia,
typhoid fever), and plant diseases
• Actinomycetes produce antibiotic compounds
• Shapes: rod, spherical (cocci), spiral, or filamentous
• Reproduce by fission (they divide in two)
Explain Virus:
• entity that contains genetic material within a protein coat that can only reproduce using the metabolic processes of a suitable host cell
Define the Disease Cycle:
- Series of events from
the initial contact between the
pathogen and plant….. to the ultimate
demise of the plant….. and the
reproduction and spreading of
the pathogen.
What are the principles of disease control?
• Exclusion
– Prevent movement of pathogen into
uninfected areas
• Eradication
– Eliminate or reduce pathogen levels on
site
• Resistance
– Improve plants ability to tolerate or
recover from attack
• Protection
– Prevent attack with chemical
