The objective is to introduce the causes, consequences, and methods of prevention of plant diseases.
3.1.1. High (18-4) and Low Temperatures
3.1.2. Oxygen Deficiency
3.1.3. Toxic Gases: Aerial Pollution (18-5)
3.1.4. Mineral Deficiency (18-6) and Excess (18-7)
 | boron deficiency (black discoloration) (18-8) |
| nitrogen fixation (18-9) |
3.1.5. Drought
| cabbage (18-10) |
| onions (18-11) |
3.1.6. Light (18-12) light, sun, and low temp.
3.2.1. Types
3.2.2. Mechanisms of Pathogenesis
3.2.3. White rot fungus in onions and garlic (18-15)
3.3.1. Mechanisms of Pathogenesis
| insects |
| wounds |
| stomata |
| ice crystal formation |
3.3.2. Types of Diseases
| wilts |
| rots |
| blights |
| galls |
3.4.1. Types
| reduced growth |
| mosaics |
| ringspots |
3.4.2. Transmission
| aphids |
| hoppers |
| mealy bugs |
| nematodes |
| fungi |
| bacteria |
3.4.3. Examples
| bean mosaic virus (18-16) |
| blackring spot virus in cabbage (18-17) |
| potato blight virus (18-18) |
| tobacco mosaic virus (18-19) |
3.4.4.1. Algae
3.4.4.2. Other Plants (toxicity and competition)
3.4.4.3. Protozoa
3.4.4.4. Insects
| aphids (18-20) |
| armyworm on corn (18-21) |
| corn borer (18-22) |
| potato beetle (18-23) |
3.4.4.5. Snails (18-24)
3.4.4.6. Rodents (18-25)
3.4.4.7. Nematodes (18-26)
| eat roots |
| cysts containing 600 eggs each (18-27) |
| attack may be selective (18-28) |
4.1.1. Reduced Growth
4.1.2. Wilts (loss of turgor pressure in leaves)
4.1.3. Chlorosis and Mosaics (green and yellow patches)
4.1.4. Blights (whithering and death without rotting)
4.1.5. Damping-off Diseases and Seedling Blights
4.1.6. Foot and Root Rots
4.1.7. Arathranose (black leasons caused by fungus) and Scab (cork formation under epidermis)
4.1.8. Leaf Spots
4.1.9. Cankers
4.1.10. Hyperplastic Deformations (abnormal outgrowths)
| penetration of in-tact surface |
| stomata |
| lenticels (root tissue) |
| floral organs |
| wounds |
| cuticle |
| stomata |
| lenticels floral organs |
| intracellular barriers |
| C12-C16 fatty acids |
| phenolic compounds |
| phytoalexins - antimicrobial substances produced by plants |
| environmental factors affecting plant or pathogen |
| climate (e.g. rainfall) |
| temperature |
| light |
| relative humidity and moisture |
| wind |
| presence of pathogen |
| competing species |
| measurement of environmental factors |
| measurement of inoculum |
| measurement of plant disease |
| modeling of epidemics |
| disease forecasting |
| soap spray (18-29) |
| rotary dusters (18-30) |
| pesticides |
| lady beetles (18-31) |
| ground beetles (18-32) |
| garter snakes (18-33) |
| salamanders (18-34) |
| marigolds (18-35) |
| quarantine |
| sanitary practices |
| pesticides |
| selective breeding |
| soil fungistasis - bacteria prevent fungal growth |
6.6.6. biological control
| Bacillus thurmgiensis (18-36) (effective against 140 insect species) |
| Cloning of Bt pathogenesis gene into plants |
| insect viruses |
7.2. What are six non-biological causes of plant disease?
7.3. Discuss six types of symptom associated with microbial plant diseases.
7.4. Make a list of disease name, symptom, and method of prevention of one pland disease caused by each of the following organisms: virus, bacterium, fungus, insect, nematode, snail, and rodent.
7-5. What are five factors which influence susceptibility of plants to biological infection or destruction?
7-6. How do microbes infect plants?
7-7. What are some barriers (characteristics of plants) to microbial infection of plants?
7-8. Briefly describe five non-biological ways to control biological plant diseases.
7-9. Briefly describe five biological ways to control biological plant diseases.
| hypertrophy | wilt | rot |
| blight | gall | mosaic |
| ringspot | aphids | armyworm |
| corn borer | nematode | chlorosis |
| cancer | hyperplastic deformation | arathanose |
| phytoalexin | soil fungistasis | Bacillus thurmgiensis |
Natural Pest Control- Assoc. of Natural Bio-Control Producers
Biological control is the use of natural enemies to control pests. Info on natural enemies, what they are and how to use them. We hope to provide useful information to you on biological control agents and their use in both commercial agriculture and home gardening.
