Transmission
Direct Transmission
- Direct contact between plants
Indirect Transmission
- Via soil or vectors such as air
- Pathogens may survive in soil and affect future plants (soil contamination)
- Additional vectors include:
- Wind
- Water (raindrops, splashes etc)
- Animals, insects and birds
- Humans, hands, clothing and tools
Key Diseases
Ring Rot (Potatoes/Tomatoes)
Caused by: Clavibacter Michiganensis Pathogen: Bacteria Transmission: Remains in soil, infects tubers and roots Transmission Type: Indirect Transmission Factors: Plants in soil, soil conditions
Tobacco Mosaic Virus (TMV)
Caused by: Tobacco Mosaic Virus Pathogen: Virus Transmission: Mechanical, touch, contact. Transmission Type: Direct & Indirect Transmission Factors: Climate, contact frequency
Potato/tomato late blight
Caused by: Phytophthora infestans Pathogen: Protist Transmission: Wind, Water Transmission Type: Indirect Transmission Factors: Wind, rainfall
Black Sigatoka
Caused by: Mycosphaerella Fijensis Pathogen: Fungi Transmission: Spores, Extended Contact Transmission Type: Direct & Indirect Transmission Factors: Wind, Rain
Global Transmission Factors
- Some varieties of crops are more susceptible than others
- Overcrowding
- Poor mineral nutrition reduces diseases resistance
- Damp, warm conditions increase spread of pathogens
- Climate change