“This year, we made some major steps forward in the organic control of thrips in chrysanthemum. By adding the predatory bug  Orius Plus, in combination with Power Food Plus, we also combat the adult thrips. At our Linflowers nurseries, we will get through the winter in an organic manner. At one single nursery, 1 cultivation round had to be done chemically, not even due to thrips, but due to an infestation by predatory bugs. Also here, we restarted the organic methods from early December. We use only few chemical agents, which also happens to be our mission; making the chrysanthemum cultivation greener and more sustainable.”

We are visiting the latest nursery of Linflowers, Rodalin 1 in Nieuwaal, and we are talking to David van Tuijl. “We grow chrysanthemums at 4 locations, on 22 hectares and we want to take on the combating of diseases and pests as organically as possible. Over the last few years we made some major steps concerning chrysanthemum, while we, at Linflowers, have been working actively to make the chrysanthemum cultivation greener and more sustainable for the last 15 years. This is a trial and error process. The chrysanthemum has a very short cultivation period of 9-10 weeks and the trick is to have an organic army ready, during those few weeks, to combat any diseases and pests.”

“Thrips control is the greatest challenge in this situation. Thrips will cause damage to the flowers, but also they spread the tobacco mosaic virus . The predatory mite Montdorensis appeared to be a good thrips controller and for the last 4 years, we have been feeding it prey mites, which enable us to grow a great population in chrysanthemum. By feeding the Montdorensis Power Food, we got to a real breakthrough in organic pest control of thrips in chrysanthemum. We just didn’t manage to do this year-round, because of the increasing numbers of thrips in the summer and the fall. This forced us to apply chemical adjustments. Spraying is not what we are after, but we can’t allow that our crop gets eaten. We must protect our crop”, according to David van Tuijl. “Royal Brinkman advised us to also make use of the new AgroBío predatory bug Orius Plus, by use of Power Food Plus. This would also be effective against the adult thrips. This spring we started scattering Orius Plus predatory bugs.”

​​​​- David van Tuijl, chrysanthemum grower in Nieuwaal​​​

Crop protection specialist Conrad van Doorn, working at Linflowers, is closely involved with the new strategy in the control of thrips using Orius Plus, Montdorensis and Power Food Plus. Conrad: “We scattered Orius Plus one time, immediately after planting the young chrysanthemum shoots. Orius predatory bugs move excellently through the crop and by starting additional feeding, using Power Food Plus right away, the population was able to grow well”. Montdorensis, as well as Power Food Plus, were scattered several times during the cultivation. The advantage is that this type of Power Food is suitable for the additional feeding of two organic controllers: Orius Plus as well as Montdorensis. At Linflowers, this is done in nursery Rodalin 1, by use of the UniMite Air diffuser, via the monorail. It will automatically move back and forth, while the predatory mites and prey mites are distributed uniformly across the crop. Conrad: “We performed counts all year and monitored how thrips, but mainly how Orius, developed in the crop. We continuously detected young Orius and the main thing; we have also noticed that the number of thrips stayed low”.

​​​​- Conrad van Doorn, crop protection specialist​​​

David van Tuijl is positive about the steps that were taken with the new Orius Plus added, in the organic control of thrips at the Linflowers nurseries. David: “At three out of four Linflowers nurseries things went well and we can make it through the winter organically. At one nursery we sadly had to run one intermediate cultivation round using chemicals. This was not caused by thrips, but by a green apple bug infestation. In the summer, these animals flies inside and they can only be controlled chemically, using which you unfortunately also lose the Orius Plus predatory bugs population”. The confidence in the biology is great, because at this fourth nursery at Linflowers, after 1 round of chemical control, we immediately started to do things organically again, early December. David van Tuijl thinks that the future for pest control lies in an organic approach. “We want to invest more in this and that is why we opted for new construction, regarding mounting of insect netting in the venting windows at this nursery Rodalin 1. This way we can prevent insects flying in from outside. We will accelerate the use of this, because also at a second nursery we decided to install insect netting early next year.”

“We’re not there yet, regarding the chrysanthemum cultivation, but there is light at the end of the tunnel”, says David van Tuijl. “We are happy to cooperate in the further improvement of organic crop protection in chrysanthemum and appreciate that there are companies like Royal Brinkman and AgroBío who, in collaboration with growers, work on this continuously. As such, at the beginning of December, we also started testing another improved type of feed; the Power Food Turbo. This will ensure Orius descendants even more quickly.”

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