In this section, you will find the growing methods in use, the growing techniques, crop protection, disease control and variety choice of tulips, hyacinths and narcissus.

back

14.9 Fungal diseases: Fusarium Infected bulbs develop greyish brown spots during storage, occasionally with concentrated rings and a clear yellow rim. They give off a distinctive, acrid smell and release ethylene. The bulbs shrivel up and sit loosely in their skins. Even healthy bulbs may contain spores of this fungus. Depending on the circumstances (especially the soil temperature) the bulbs are infected from the base of the root crown in the first weeks after planting. Diseased bulbs will not emerge. In less serious cases growth will be retarded, flower tips will turn yellow and flower buds will desiccate. A longitudinal dissection of a bulb clearly shows that the stem turns brown from the base upwards. Bulbs infected with Fusarium release ethylene into the soil which may lead to retarded growth and even bud desiccation in neighbouring plants. Cause The disease is caused by fungus Fusarium oxysporym f-spec. tulipae. In tray cultivation it thrives in high planting temperatures and during long periods in the greenhouse. In the cultivation of 5°C tulips there is a high infection risk especially in early crops, as the bulbs undergo temperature treatments that encourage the development of the fungus. Infected bulbs release ethylene gas, which during storage may lead to “gumming”, open shoots, multi shooted crops, bud necrosis and a somewhat greater risk of blind flower buds in the other bulbs. Control - Ventilate infected batches thoroughly when in storage. - Remove infected bulbs. - Disinfect bulbs (see bulb infection) or plant at soil temperatures of 9°C or less (5°C tulips 12°C or less). Never plant in temperatures above 13°C. If necessary, plant later. - Remove all bulbs that do not emerge.