The following points highlight the eight chief methods used for the transmission of plant viruses. The methods are: 1. Seed Transmission of Virus 2. Transmission by Vegetative Propagation 3. Transmission by Mechanical Means 4. Transmission by Cuscuta 5. Soil Transmission 6. Insect Transmission 7. Transmission by Fungi 8. Some Soil Inhabiting Viruses have Nematode Vectors. Method # 1. Seed Transmission [...]
The following points highlight the six main symptoms of viral diseases. The symptoms are: 1. Mosaic Spotting 2. Ring Spotting 3. Chlorosis 4. Distortion 5. Necrosis 6. Breaking of Blossoms. Symptom # 1. Mosaic Spotting: In this case usually the leaves, sometimes the blossoms and other parts of the host plants show spots or patches of light green, yellow or [...]
The following points highlight the two main theories on living hypothesis of viruses. The theories are: 1. Organism Theory 2. Molecular Theory. Theory # 1. Organism Theory: The supporters of the living hypothesis argue that growth and reproduction are chief distinctive characteristics of living things (organisms). Viruses possess both. They grow, reproduce and undergo mutations and become adapted to the [...]