Lettuce in greenhouse

Managing Water Quality with Huwa-San TR-50 to Prevent the Spread of Phytophthora Cryptogea in Lettuce

Lettuce growing conditions are increasingly challenging due to pathogen pressure and restrictions, which makes effective water treatment essential for producing high-quality lettuce. On top of this, the cultivation of lettuce in hydroponic systems has been facing the challenge of Pythophtora cryptogea for years. P. cryptogea causes severe root rot, leading to plant growth inhibition or even complete plant rot.
25 March 2025

Understanding P. Cryptogea

Phytophthora cryptogea is a significant threat in hydroculture. This pathogen is a member of the oömycetes family, which includes species known to parasitise a wide range of agricultural, ornamental, horticultural and forest plants. They are ubiquitous in soil and water throughout the world. Most of these species have a wide host range.

This soil- and waterborne pathogen can quickly degrade roots, causing them to rot and completely disappear. In hydroponic lettuce and chicory systems the pathogen thrives in waterlogged conditions, rapidly spreading and infecting roots.

HydroPhyt Trial – Preventing Phytophtora Cryptogea

In the spring of 2024, a trial was conducted as part of the HydroPhyt project, a VLAIO initiative focused on managing P. cryptogea in hydroponic lettuce and chicory systems. VLAIO is the Flemish agency that supports businesses and innovation through funding, advice, and guidance. The primary goal of the project is to enhance the integrated control of P. cryptogea, while improving water quality through sustainable practices. The trial, conducted on the Emeldia lettuce variety, explored preventative water treatments using advanced technologies to suppress the spread and breeding ground (biofilm) of the pathogen.

Graph HydroPhyt Trial Emeldia Results
Fig. 1: HydroPhyt Lettuce Trial Results (Emeldia lettuce variety)

The Set-up: Huwa-San TR-50 Combined with Ultrafiltration

In one of the set-ups, Huwa-San TR-50 was combined with an ultrafiltration system. This trial lasted for 6 weeks. Huwa-San TR-50 was injected at approximately 15 ppm hydrogen peroxide into the clean drain to further suppress pathogens. The ultrafiltration system (Kathari) filtered water at 20 nanometres, allowing nutrients to pass through while removing harmful pathogens.

Huwa-San TR-50, in combination with the ultrafiltration system, delivered excellent results in this trial. The test results identified Huwa-San as an effective water treatment solution, thereby managing P. cryptogea. The product demonstrated superior efficacy, significantly improving root health, root mass, and overall head weight of the lettuce, outperforming the competitor treatments. For the treatment with Huwa-San in combination with the Kathari ultrafiltration the rootscore was > 5, whereas the score was < 5 for competitor A and B (see fig. 1). The results also show a better development of the root system with the treatment with Huwa-San and Kathari ultrafiltration than competitor A and B.

Lettuce compared to competitor
Left to right: Competitor A, Huwa-San + Kathari, Competitor B

Furthermore, Huwa-San degrades into oxygen and water post-disinfection, leaving no harmful residuals and providing oxygen-rich water. Huwa-San enhanced the water quality, creating an environment less hospitable to P. cryptogea. This highlights Huwa-San’s efficacy and ability to optimise lettuce cultivation.

For growers seeking to optimise their hydroponic systems and mitigate the risk of P. cryptogea, Huwa-San TR-50 is therefore an excellent choice. It is advised to integrate Huwa-San into an entire cleaning and disinfecting protocol for your greenhouse to achieve the best results for your greenhouse crops.

For tailor-made advice about the application of Huwa-San in hydroculture, please don’t hesitate to contact us.