Hymenomonosis

Hymenomonosis is a plant pathology caused by the microorganism Hymenomonas roseola. Although frequently identified as a microscopic golden alga, its presence in agricultural and horticultural substrates can become problematic, negatively impacting the physiological balance of cultivated plants, particularly in controlled environments like greenhouses.

This condition primarily affects young seedlings, ornamental plants, and various greenhouse crops. Plants characterized by frequent irrigation needs are the most vulnerable, as constant soil moisture provides the necessary environment for Hymenomonas roseola to bloom and form biofilms on the substrate surface.

The primary clinical signs of infestation include the formation of a distinct pinkish or rusty-brown film on the soil surface, pots, and stems at the base of the plant. Infected plants show symptoms of chlorosis, stunted growth, and general loss of vigor, as the algal crust physically restricts oxygen diffusion to the root zone and competes for nutrients.

The development and spread of Hymenomonas roseola are heavily dependent on environmental conditions, specifically high humidity, water stagnation, and poor ventilation. The pathogen thrives in temperatures ranging from +18°C to +25°C, especially in environments with high nutrient levels in the substrate, which promotes rapid colonization.

Prevention and management require strict cultural practices, primarily focusing on moisture control. Key measures include maintaining efficient drainage systems, implementing regular surface cultivation (raking) to break the crust, and ensuring proper airflow. In severe cases, professional-grade algaecides or fungicides approved for the specific crop should be applied to eliminate the pathogen and restore soil health.