Citrobacter

Citrobacter freundii is a Gram-negative, facultative anaerobic bacterium recognized in agricultural pathology as an opportunistic pathogen. While commonly associated with other environments, it frequently acts as an agent of bacterial soft rot in a wide variety of cultivated plants, including vegetables and succulent fruit crops, often compromising both field yield and post-harvest quality.

The host range of this pathogen is extensive, targeting fleshy organs such as potato tubers, carrots, tomatoes, and leafy greens. Infection typically begins through wounds or natural openings like stomata and lenticels. Once inside the tissue, the bacteria secrete enzymes that degrade pectin, causing the cellular structure to collapse rapidly.

Symptoms of an infection include the appearance of water-soaked, translucent lesions that expand quickly. As the disease progresses, the internal tissues of the infected plant parts become soft and mushy, frequently accompanied by an unpleasant odor. This rapid tissue breakdown is a hallmark of the severe damage inflicted by this bacterial agent during the infection cycle.

Environmental conditions play a decisive role in the outbreaks of Citrobacter freundii. High relative humidity and the presence of standing water on plant surfaces, combined with temperatures ranging from 20°C to 30°C, create an ideal environment for bacterial multiplication. In storage facilities, poor ventilation and high moisture content often lead to rapid secondary infections and total loss of produce.

Control strategies for this bacterium center on strict sanitation and preventive maintenance. Effective measures include avoiding physical damage during harvest, ensuring thorough drying of produce before storage, and maintaining consistent refrigeration with proper airflow. Additionally, managing insect populations that cause plant wounding and utilizing crop rotation helps to reduce the prevalence of the pathogen in the soil environment.