Bacterial wilt of pepper

The causal agent of this disease is the Gram-negative bacterium Pseudomonas capsici, which belongs to a group of dangerous plant-pathogenic microorganisms. This disease is classified as a bacterial wilt that invades the vascular system, effectively blocking the transport of water and essential nutrients from the roots to the plant canopy.

The primary host for this pathogen is sweet pepper (Capsicum annuum), though it can also affect other members of the Solanaceae family. The disease is a significant threat in both greenhouse environments and open-field cultivation, often appearing during the peak stages of plant development and fruit setting.

The initial symptoms are characterized by transient wilting of leaves during the hottest hours of the day, which recover during the night. As the infection progresses, the wilting becomes permanent. Cross-sections of the lower stem will typically reveal darkened or discolored vascular bundles, and in high humidity, bacterial ooze may be present at the wound sites.

Environmental conditions favoring the development and spread of Pseudomonas capsici include high soil temperatures and excessive soil moisture. The bacteria can persist in soil for long periods, spread through contaminated irrigation water, infected seeds, and infected farm equipment, entering the plant through natural openings or mechanical wounds.

The economic impact of bacterial wilt is severe, as infected plants usually die, leading to significant yield losses. Effective management requires an integrated approach: using disease-free seeds, implementing strict crop rotation, ensuring proper soil drainage, practicing greenhouse sanitation, and promptly rogueing and destroying infected plants to prevent further spread.