Principles of Plant Pathology Flashcards
What is Plant Pathology?
The science concerned with Plant Disease
What is Plant Disease?
Any deviations from the normal growth of fruit
What does Plant Pathology study?
- Microorganisms and environmental factors that cause disease
- Mechanisms by which these factors induce disease
- Methods of disease control
What was Plant Pathology associated with since the beginning of agriculture?
Crop failures and famines
What are the four types of impacts Plant Diseases have?
- Famine
- Economic
- Agricultural
- Ecological
What was Coffee replaced with because of Coffee Rust?
Tea
Is a disease usually one pathogen?
No. Often an interaction of multiple pathogens
What causes Potato Early Decline (PED) Syndrome?
Interaction between Verticillium wont and nematodes
What are the three factors of Non-Infectious or Abiotic diseases?
- Physical Factors
- Pollutants
- Chemical Factors
What are the five Physical Factors of Non-Infectious or Abiotic diseases?
- Extremes of temperatures (hot or cold)
- Excess or lack of soil moistures
- Hail Damage
- Lightening Damage
- Implement Damage
What are the two types of pollutants associated with Non-Infectious or Abiotic diseases?
- Air-borne
2. Water-borne
What are the three Chemical Factors associated with Non-Infectious or Abiotic diseases?
- Toxicity of fungicides, insecticides or herbicides
- Mineral toxicities or deficiencies
- pH extremes
What are the effects of extreme weather conditions?
- High Temperature causes heat stress on plants or sunburn damage of fruit
- Frost dampte to vegetables or crops
What can cause Iron deficiencies in plants?
High pH soils
What happens to nutrient deficient plants? In this case Iron.
- Leaves cannot access enough Iron to make chlorophyll
- Increase in pH locks up the Iron
What effects do Nutrient toxicities cause?
- Necrotic lesions
- Cuffing or cupping of leaves
- Chlorosis
Is a Non-Infectious or Abiotic disease transmissible or non-transmissible?
Non-Transmissible
Is an Infectious or Biotic disease transmissible or non-transmissible?
Transmissable
What are the four factors of Infectious or Biotic diseases?
- Microbial Pathogens
- Plants
- Insects, Mites, Nematodes
- Birds, Mammals
What are the Infectious or Biotic Microbial Pathogens?
- Fingi
- Bacteria and Mollicutes
- Viruses and Viroids
What are the Infectious or Biotic Plants?
- Parasitic Higher plants
2. Competitors (Weeds)
Where can the symptoms of plant diseases be found?
- Roots
- Leaves
- Seeds
- Flowers
What are the four main symptoms of plant disease?
- Necrosis
- Wilting
- Abnormal growth and differentiation
- Fruit and Foliage Discolouration
What is Soft Rot Necrosis?
The tissue rapidly becomes watery and loses coherence
What is Dry Rot Necrosis?
Less rapid than a soft rot
Are lesions localised or progressive?
Both. Can be localised (leaf spots) or progressive (gradually spreading)
How do diseases cause a permanent water deficit in plants?
- Interference with water and nutrient absorption by roots
- Interference with water conduction within the plant
- Loss of control of transpiration
- Infection of roots
- Pathogens can get in Xylem Vessels and produce toxins
What is associated with the wilting die-back and damping-off of plants?
Diseases that cause a permanent water deficit
What does abnormal growth and differentiation cause or affect?
- Affects hormonal balance
- Creates Galls, Nodules, Callus tissue
What are the effects of Fruit and Foliage Discolouration?
- Chlorosis
- Anthocyanin
What is Chlorosis?
Yellowing due to lack of Chlorophyll
What is Anthocyanins?
Red and Purple pigmentation
