Ordering Isolates

Naktuinbouw is in charge of the Plantum reference collection of about 70 isolates for resistance testing in vegetable crops. Naktuinbouw also maintains its own collection of reference isolates, for example isolates used for Resistance tests in Ornamental crops.

The Plantum reference-isolate collection is based on an Agreement of Naktuinbouw and seed companies and is administered by Plantum. The companies cover the costs for maintaining the collection and also contribute in kind. The Working Group in charge of the isolate collection is also in charge of occasional workshops about challenges encountered in the field of resistance testing.

The Participants of the Plantum isolate collection are: Bayer CropScience, Bejo Zaden, Enza Zaden, Monsanto Holland, Hazera Seeds, Pop Vriend Seeds, Rijk Zwaan, Syngenta Seeds. The Plantum isolate collection comprises reference isolates of viruses, bacteria, fungi and nematodes. The isolates are used for testing resistances in DUS variety research. Naktuinbouw  validates the isolates in biotests by inoculating sensitive varieties, and, if possible, also varieties with race-differentiating resistances.


A Material Use Agreement (MUA) must be signed before delivery, prohibiting further distribution of the isolate.

Third parties have limited access to the Plantum isolate-collection. We can deliver a maximum of 4 isolates per calendar year to third parties. Third parties pay a fixed tariff per isolate. The tariff is given in our tariff list. This tariff does not include the costs of shipping.

The Participants can use the isolates of the Plantum isolate collection without paying the tariff.

Delivery time

Most isolates can be delivered within 1-2 weeks. For fresh material of obligate parasites like Bremia lactucae and Peronospora farinosa f. sp. spinaciae the delivery time may vary from one month to one year.