Challenge: Combating disease in deep-water hydroponic systems is a battle that remains to be won. Root diseases can be caused by a multitude of factors including contaminated water or insufficient aeration in deep water hydroponic systems and can devastate the crop. Kirsty Wright (Plant Pathology Project Manager at Stockbridge Technology Centre), AHDB SCEPTREplus and CHAP joined forces to investigate the problem of root rot pathogens for lettuce growers.

Study Title: ‘Root rot control in deep-water hydroponic culture of lettuce’

Background: Hydroponic systems are gaining favour in the lettuce production industry due to the increased ability to produce a crop without weed competition, combined with increased efficiency in energy, fertiliser and water usage.

However, in deep-water hydroponic systems such as the CHAP funded bespoke hydroponics facility on site at STC, oomycete pathogens such as Phytophthora that thrive in water can cause severe damage to crop roots leading to reduced vigour and yield. UK hydroponic lettuce growers currently have no access to fungicides (conventional or biopesticide) for direct application into hydroponic systems for control of such disease threats, nor to readily available testing systems.

Methodology: The AHDB SCEPTREplus project, led by Kirsty Wright at STC was designed to investigate potential treatments using the CHAP bespoke deep-water hydroponics tanks (part of the Advanced Glasshouse Facility) at STC. The system was used as its flexible experimental design provided the perfect test bed for such analysis. The bespoke suite consists of 60 individual 300-litre deep-water tanks, each with a heater and pump for temperature control and efficient circulation. This model testing facility was used to study the use of a range of biopesticides and novel actives against Phytophthora root rot of lettuce.

The trial was a success and gave promising results as to what range of treatments could be approved for use in the future. One treatment, for example, gave excellent control of disease symptoms which lasted through until harvest.

Kirsty Wright said “The method of application is a statutory condition of pesticide approvals and application directly into the nutrient solution of a deep-water hydroponic system is unchartered territory. The trial identified products that were very efficacious against the pathogen and this was very encouraging, but there are further challenges to be addressed in terms of pesticide fate in these systems. Increasing our understanding of this is key to unlocking the potential for these products to be approved for use. The CHAP deep-water hydroponics facility would provide a useful tool in investigating this further.”

AHDB SCEPTREplus commented that the trial demonstrated first-hand the types of treatments that could be compatible with such growing systems and may pave the way for an exciting future for crop protection.

Conclusion: Successful research was conducted at STC using the bespoke CHAP deep-water hydroponics research facility giving promising results for the future of the control of devastating disease which can quickly take hold of such systems.

This use of the CHAP hydroponics facility provides a perfect example of its use in the testing of future plant protection programmes, an aspect fundamental to the sustainability of the UK food system in an era of legislative and climatic change.

This Case Study was prepared for the CHAP website by Dr Lauren Branfield of Stockbridge Technology Centre.

For more information go to our Advanced Glasshouse Facility capability page or visit Stockbridge Technology