How to prevent thrips in chrysanthemum crops

Last year, chrysanthemum growers started to use Mass trapping to combat thrips. "This method certainly works, but it is not enough" says Nico Kiep from Nieuwaal, The Netherlands. Together with Koppert and his supplier Vos Capelle, he investigates the precautionary measures.

From left to right Nico Kiep, Roland van Hemert and Mark Kolbach.

Thrips are a serious problem in the 9ha sized greenhouse of Nico Kiep. However, it's not only Kiepflower, but all chrysanthemum growers that are dealing with this problem. Kiep: "Over time, chemical crop protection products are becoming less effective. This leads to spraying not being an option anymore."

Tripartite action plan
Together with Koppert and Vos Capelle (who advises Kiepflower and supplies all crop protection products twice a week) Nico Kiep tries to improve the current method of controlling and combating thrips. A tripartite action plan has been set up. First, the adult thrips need to be removed by means of the Horiver traps. Then the predatory mite Amblyseius swirskii (Swirski-Mite) will be released to combat the larvae of the thrips. Finally, the entomopathogenic nematode Entonem will be released to prevent pupae and prepupae of thrips (in every stage).

Looking for new solutions
Nico Kiep is open to looking for new solutions. At the three 1000 m2 sized test fields, he, consultant Ellen Klein of Koppert and adviser Mark Kolback of Vos Cappelle are investigating three different regimes:

Entonem, mass trapping and Amblyseius swirsldi (Swirski-Mite)
Entonem, mass trapping and Amblydromalus limonicus (Limonica)
Entonem, mass trapping, Swirski-Mite and Macrocheles robustulus (Macro-Mite).

Ellen Klein: "We will release Limonica as an alternative for Swirski-Mite because it is more revengeful than the swirskii. Limonica combats the first and second larvae stage of the thrips. In contrast, Macro-Mite is specialized in prepupae and pupae of thrips. We are hoping to develop a good solution for controlling thrips in all stages with method 3, the most intensive method. In the third, sixth and ninth week of cultivation, we will rinse the stems and we will count the traps. By doing this, we expect to get more insight into the behaviour of the thrips and the predatory mites."

Consultant Ellen Klein collects stems to rinse in the lab of Koppert.

No way back
As an extra precaution, growers can consider additional steaming. Ellen Klein: "Increasingly more growers are considering doing this."

Nico Kiep is eager to discover this wide approach. Chemical crop protection products do not work anymore. Therefore, regarding thrips, there is no way back.

For more information
Koppert Biological Systems
Bio Journaal, April 2015
Veilingweg 14
2651 BE Berkel en Rodenrijs
Tel: 010-5140444
Fax: 010-5115203
www.koppert.com