Bacterial pathogens
Bacteria enter through wounds, hydathodes, or natural openings. Water-soaked lesions that may turn necrotic are typical. Yellow halos often surround spots.
Confirmation methods
- Streaming bacterial ooze from cut lesion in water.
- Gram stain of exudate under microscope.
- Isolation on selective media in lab.
Viral pathogens
Viruses require living cells; they cannot be cultured on media alone. Symptoms: mosaic patterns, stunting, ring spots, distorted leaves.
Transmission
Many plant viruses spread via aphids, whiteflies, nematodes, or pollen. Control focuses on vector management and certified clean stock.