It was Cock van der Voort, the father of Jack of SchermNed, who came up with an insect mesh filter he developed himself many years ago. It is an alternative to the harmonica netting, much better known in horticulture.
"We have been working with it for years but have never really given it much publicity," Jack confesses. Together with Terry and Mark, and the rest of the team, they now run the family business. "At first, it was mainly breeding companies that asked for it. In recent years, we have also started installing the insect mesh filter at many cucumber growers."
Climate
And now, at the Westland family company, they see the insect mesh filter becoming known in other crops as well. Jack mentions gerbera growers and also tomato growers. "As more growers start working with it, we are also getting new results," he says. Nine years ago now, a TNO study was conducted. A patent on the product followed. The research at the time already showed that the mesh filter, despite being cheaper than harmonica mesh, was not inferior to the more expensive product in terms of performance.
"What we certainly hear more and more lately is that it is possible for growers, even after installing the insect mesh filter, to continue growing in the same way, both with the climate computer settings and their heads. For example, gaps with the windows remain the same with our filter. The gap is not full of mesh. New settings are not needed. The temperature increase with the filter is a maximum of 1 degree Celsius. Growers are very enthusiastic about it."
A mesh size of 0.27x0.77 millimeters is the choice in 90 percent of cases in horticulture, although SchermNed is now also seeing 0.77 x 0.77 in increasing numbers.
Getting some air
This is evidenced by, among others, the story of plant grower WPK, which has had department after department screened off. The positive results, both for keeping out insects and in terms of climate - "when superimposing the charts, we saw no differences in temperature and absolute and relative humidity" - meant that a tomato grower who came to see the plant grower also took the plunge into netting. "And now we are seeing even more tomato growers making the move."
The mesh specialist explains that normally the vents 'scoop' the wind. With harmonica mesh, also supplied by SchermNed and more often used in new-build situations, the wind passes by more. "With our mesh filter system, you still create air, thanks to the shape of the mesh on the inside of the window. Partly because of this, it remains possible to create good climate."
Self-cleaning
The more growers work with the insect mesh filter, the more knowledge they gain about the innovative system, including about cleaning the mesh. "For example, a cucumber grower working with our mesh pointed out that the mesh cleans itself. That's because when the air window opens, the mesh is sucked up a bit." Spraying it clean is also possible, as WPK does, but so does Florein Gerberas, for example. "From the greenhouse deck, it's done in a matter of seconds," he says.
For more information:
Carl Stougie 
John van Hasenbroek
Jack van der Voort
SchermNed B.V.
Tel.: +31 (0)174 62 22 14
[email protected]
www.schermned.nl