Uncommon disease symptoms caused by Fusarium oxysporum in tulips forced in the glasshouse after pre-cooling at 5°C

Rapidly developing disease symptoms not normally found in tulip bulb cultivation in The Netherlands are described. Mycelium of the fungus is present mainly in the parenchymatic tissues, giving further evidence that the fungus is not a vascular parasite in tulips. There are indications that enzymes or other compounds are involved in the syndrome. Possible factors influencing this uncommon disease development are mentioned.