Over the past two years, the use of UV-C technology in strawberry cultivation has gained significant traction. As issues with mildew emerged over the last years, growers swiftly started looking for alternatives to traditional spraying methods. In Belgium, four suppliers collaborated and participated in an initiative set up by Coöperatie Hoogstraten to offer growers a thorough look at what they have to offer.
The tour included visits to the farms of Luc Krijnen, Jan Jansen, Frank Boeren, and Raf Quirijnen, where attendees could see the robots from Micothon, Nouws Mechanisatie, Octiva, and Bogaerts in action. Between the visits, a lunch and presentation were held at Proefcentrum Hoogstraten. In total, 63 unique visitors attended, excluded the representatives from the presenting companies.
© Bogaerts Greenhouse Logistics
Demonstration with the UV-C robot from Bogaerts at grower Heiken
Use against mildew
UV-C technology helps in controlling mildew, and employing a robot for this task also reduces labor costs, particularly since the robot can operate during nighttime hours. An important condition for operating at night is that a robot can drive autonomously. During the tour, the biggest differences between the various suppliers were seen in the choice of driving systems.
© Octiva
The Lumion from Octiva in action
On pipe rails or (caterpillar) tracks
Octiva and Bogaerts have developed a system that can (also) operate on pipe rails. Micothon offers a similar system; however, in the greenhouse at Gestelberries, their robot travels on pneumatic tires over the ground cover. At grower Jan Jansen's facility, the robot is utilized for rack cultivation and within the company's foil greenhouses. This particular robot, from Nouws Mechanisatie, is equipped with caterpillar tracks.
While the robots from Nouws Mechanisatie operate on diesel-powered caterpillar tracks, Micothon chooses an electric option that requires a plug. The decision to work with a wide span necessitates high capacity, which is not achievable with batteries, as Peter van Dongen explained to the interested group of visitors.
© Thijmen Tiersma | HortiDaily.comPeter van Dongen from Micothon explains how the UV-C lamps illuminate the crop at Gestelberries.
Dosage
Research has already provided significant insights into the application of UV-C in strawberry cultivation. For instance, Proefcentrum Hoogstraten has studied the maximum dosage the crop can tolerate and the optimal dosage for effective mildew control. They determined that the ideal dosage is 100 joules per square meter per hour, applied in three rounds per week.
In practice, this means that growers have a robot pass through a row every two days. Both Nouws Mechanisatie and Micothon can cover approximately 3 hectares per night. This approach helps in combating mildew, and grower Luc mentions that he can cautiously reduce the number of chemical sprays used against mildew. However, he hasn't completely switched to relying solely on UV-C yet. He is aware that some of his colleagues who do not use robots are already experiencing mildew issues at the end of March. In his greenhouse, however, everything is going well.
© Thijmen Tiersma | HortiDaily.comDemonstration of the UV-C robot from Nouws Mechanisatie at grower Jan Jansen
A rapid increase in demand
In addition to its effectiveness against mildew, researchers at Proefcentrum Hoogstraten have also noted a side effect on spider mites, achieving about 60% mortality thanks to UV-C exposure. This prompts the question of whether UV-C also affects biological control agents. This aspect has been investigated, and it was found that the limited impact on these agents does not outweigh the benefits of effective mildew control. Researcher Stef Laurijssen emphasizes the importance of using the correct dosage, noting that a decrease in predatory mites was only observed at dosages between 200 and 220 joules. It's also known that leaf burn can occur at dosages around 600 to 700 joules.
Currently, Coöperatie Hoogstraten has around thirty UV-C systems in operation among growers. The cooperative offers assistance to growers in obtaining subsidies for their purchases. The systems from both Micothon and Nouws Mechanisatie each cost over 100,000 euros. It is anticipated that as technology advances, practical experience accumulates, and with events like these comparison days, more growers will be encouraged to make a purchase. The four suppliers who participated on Friday are eagerly awaiting new orders.
© Proefcentrum HoogstratenStef Laurijssen gave a presentation
View the full photo report of the morning from our Dutch friends at Groentenniuews here with also some images from the afternoon program, thanks to Bogaerts, Octiva, and Proefcentrum Hoogstraten.
No demonstration without moving images, of course. Below are videos of the demonstrations by Nouws Mechanisatie and Micothon.