"LED has potential to end use of pesticides in farming"

Research is proving that light produced by LEDs has the ability to speed up plant growth and improve the taste of fruit and vegetables. However, researchers in the United States are also proving that LED light is able to reduce disease in plants, a discovery that could, ultimately, lead to the redundancy of expensive and unpopular pesticides.

by Robert Leeming for Lux Magazine

What is more, early research suggests that the same wave lengths of light produced by LED that improves flavor, can also control pathogens.

Lux caught up with Jaimin Patel, a plant pathologist at the Lighting Research Center of the Rensselaer Polytechnic Institute in New York, who is currently conducting a range of studies and research into plant pathogens, the microorganisms that cause diseases to spread in plants.

Could the use of expensive and unpopular pesticides in greenhouses soon be a thing of the past?

Patel aims to understand which light wavelengths are beneficial to pathogens and what wavelengths will do them more harm than good, information that will be passed onto to growers, in the hopes of decreasing plant disease.

Patel’s team, in conjunction with partners at New York’s Cornell University, have conducted studies on the effect of LED and ultraviolet light on strawberries, rosemary, cucumber, as well as a string of other fruit and vegetables, and each time the light has been found to reduce pathogens whilst increasing production.

Jaimin Patel is a plant pathologist at the Lighting Research Center of the Rensselaer Polytechnic Institute in New York, who is currently conducting a range of studies and research into plant pathogens.

‘Downy mildew (primarily a disease of the foliage) and powdery mildew pathogens (a fungal disease that effects a wide range of plants) are very sensitive to a certain type of light,’ Patel told Lux.

‘Human beings need light to be able to live and so do pathogens,’ Patel continued. ‘Pathogens are living entities too, therefore they also require light to regulate their daily growth and development.'

Sun light has many different kind of waves within it, a wide ranging spectrum that ranges from x-rays to radio waves to visible and ultraviolet light.

The difference between downy mildew and powdery mildew. The occurrence of both plant pathogens can be reduced if grown underneath LED light.

LEDs can be controlled to produce a particular spectrum of light that utilizes what is required for the job at hand. So, for example, a spectrum of light can be created that can harm pathogens and benefit plant development.

‘This is a new area of research and studies have only been carried out on a limited number of diseases,' Patel added. 'I cannot say confidently that LED light has an effect on all pathogens, but as a living organism I can certainly say that every living organism depends on light.’

What is more, if light is proved to be an effective suppressor of pathogens across a range of plants, then this means that expensive and some say, unhealthy, pesticides will no longer be required to keep plants healthy, a plus point not only for the grower, but also, many would say, for the consumer too.

‘People like to buy food that is organic and free of pesticides and one of the reasons I am coming the Lux Horticulture Conference on the 23 May in Eindhoven, is to extol the benefits of light in horticulture,’ Patel says.

But with the expense of LEDs often preventing growers from investing in the technology, they have to see not only the light source reducing pathogens, but also increasing yields.

‘I want to make sure that my research controls diseases as well as increases some of the crops marketability parametres, for example in the case of basil, LED light could be used to increase the weight of basil leaves, meaning that if the plants are sold by weight then there is going to be financial advantage for the grower.

‘An extensive effort is required, not only by scientists, but also by stake holders and politicians to ensure that the benefits of lighting technology in horticulture are made known to end users,’ Patel continued.

The university teams at Cornell and Rensselaer Polytechnic Institute have received federal funding for their research, which goes to show that there is an appetite on the part of governmental decision makers to get behind this technology.

‘I am interested in the sensitivity of pathogens to different wavelengths of light. The next step is to understand if these wavelengths can be used to enhance plant growth, then I can make sure that the technology can not only be used to control pathogens, but will also be useful for plant development.’

A revolution is happening in horticulture. It’s a seismic shift that will change fundamentally how we grow plants – and it’s all down to lighting. Lux's Horticulture Lighting Conference will take place in Eindhoven, The Netherlands, on Tuesday 23 May 2017. To find out more information and to register to attend please click here.