Gebr. Nederpel pot plants

 ‘The climate in the greenhouse is exactly what I had hoped for’ told pot chrysanthemum grower René de Bakker from Wateringen. He had insect netting installed by SchermNed at one of his three locations in March. Despite the ‘crappy summer’, René soon noticed the benefits of the insect netting: ‘During the hot days we did have, the temperature in the greenhouse with netting remained the same as that in the greenhouse without netting.’

Why not harmonica netting, but rather insect netting?

‘We first looked at harmonica netting, which is widely used in greenhouse vegetable growing. But we found it a disadvantage that this type of mesh increases the temperature in the greenhouse, as it limits the ventilation capacity.’

Eventually, after contacting SchermNed, Gebr. Nederpel opted for the insect mesh filter developed by the Westland company itself. Two years ago, they started thinking about investing in insect mesh. René and his colleagues had also sought advice from other growers who already had experience with this type of netting. ‘We talked to companies that wanted to keep moths and other insects out. Their positive experiences gave us the confidence to choose this netting.’

Keeping lice and thrips out

In the greenhouse with pot chrysanthemums, it is essential to keep out pests such as lice and thrips. ‘The pesticide package is getting smaller and smaller, so you have to start looking at how you can keep those critters out anyway,’ says René.

Insect netting is not yet widely used in pot chrysanthemums. Nevertheless, it was decided to screen off one entire greenhouse. Carl: ‘That gives a better picture than when you start testing in one or a few departments, because then you have to screen off a lot or make all kinds of arrangements.’

With the insect mesh filter, René manages to keep aphids and most of the thrips out. ‘Thrips that fly in with their wings open no longer enter our greenhouse. If you really want to keep all thrips out, you have to leave the windows closed,’ René points out with a laugh.

Looking ahead

René hopes to have all his sites fitted with the mesh in three years' time.

‘Because we have a location with netting next to one without, we can compare well. When it got really hot a few weeks ago, I noticed that the temperature rose in both greenhouses, but it was no hotter in the greenhouse with insect mesh filter than in the greenhouse without mesh.’