Netherlands: No future for chemical crop protection in Brassica propagation

Plantenkwekerij Gitzels BV in Wervershoof, North Holland, specializes in the propagation of starting material for commercial brassica growers. A lot of attention is given to R&D, which is the responsibility of R&D manager Matthijs Woestenburg, including the yearly grow-out trials. To make these trials successful, they have switched from a fully chemical to an integrated approach.

In the grow-out trials, the new fruiting vegetable varieties are evaluated on crop structure and fruit development in the developmental phase. Matthijs: "During these tests we have a relatively short growing period at a time of the year in which the pest pressure is generally high in and around the greenhouse. For this reason it is a challenge to make everything run smoothly. Last year's tests were plagued by whitefly, thrips and caterpillars. This was a challenge for both plants and employees. So it was time to try something different."

"Last year we still had a completely chemical pest control approach, but this has no future we think. We had to take a different path and the organic approach was the obvious one. An integrated approach fits well into our policy of producing a high quality product in a sustainable way with minimum use of plant protection production."

Gitzels launched their organic plant protection plan this year, consulting with crop advisors Hans van Vliet and Han Opstal of Van Iperen. “We’re using the Amblyseius swirskii predatory mite in peppers. Due to its great development speed it has managed to control both trips as whitefly. For tomatoes we chose the Macrolophus predatory bug and the Encarsia parasite wasp. Both have been effective against whitefly. This year the tests have been almost pest-free."

It has been a positive and educational experience for Matthijs. "I learned that you shouldn’t automatically think that it won’t work. Natural predators are actually effective!”

The R&D manager believes that time plays a crucial role. "You have to check the crop every day. Monitoring the development of pest and predator is necessary for a good result. And fortunately there’s ample time."

Matthijs is also very happy about Van Iperen’s time investment in the project. "Van Iperen’s support has been indispensable. Hans visits every 14 days and we have phone contact in between. And it’s great to get the organic plant protection product delivered upon request every week. The success of this approach is really due to this collaboration."

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