Pseudomonas aeruginosa

Pseudomonas aeruginosa is a Gram-negative, aerobic, rod-shaped bacterium belonging to the genus Pseudomonas. In agricultural contexts, it acts as a facultative phytopathogen capable of infecting a wide range of botanical hosts. Its metabolic versatility and ability to thrive in diverse environments make it a persistent threat to agricultural production.

The pathogen is known to cause various plant diseases, including soft rots, leaf spots, and tissue necrosis. Susceptible crops include vegetables like tomatoes, potatoes, and cucumbers, as well as several ornamental species. The bacteria infect the host by entering through stomata, hydathodes, or physical wounds caused by environmental stress or agricultural practices.

The biology of the pathogen is driven by its ability to rapidly colonize the intercellular spaces of host tissue. By producing extracellular enzymes that degrade plant cell walls, the bacteria cause tissue maceration and the characteristic formation of bacterial ooze. This organism survives well in soil, water reservoirs, and decaying plant matter, serving as a reservoir for annual infections.

Development and spread are favored by high humidity (often exceeding 80%), moderate to warm temperatures, and stagnant water on foliage. Transmission primarily occurs through contaminated irrigation water, infested seeds or transplants, and contaminated agricultural machinery, which can easily spread the bacteria throughout a field or greenhouse facility.

The economic impact of Pseudomonas aeruginosa includes significant yield losses and post-harvest spoilage. Effective management requires an integrated approach to break the disease cycle and limit bacterial proliferation:

• Utilizing certified disease-free planting material.
• Implementing strict sanitation protocols for tools and irrigation systems.
• Maintaining proper drainage to reduce leaf wetness.
• Applying copper-based bactericides or biological control agents.