Basal Rot (caused) of Flowering bulbs

Disease Information

Basal Rot (caused

 by FusariumoxysporumF.sp. narcissi)

Symptoms and damage

This is the most serious daffodil bulb disease which although it was described a hundred years ago as a serious threat, is growing in intensity as a result of hotter summers. The initial symptoms is the premature dying back of the foliage which when investigated, or at lifting time, reveals a soft or mummified bulb containing a chocolate brown rot spreading upwards from the base plate. At this point recovery of the bulb usually becomes impossible. The bulbs can become infected in storage or after planting and spores become widespread and are viable for over ten years in the soil.

Management

Control is very difficult even commercially. Resistant cultivars such as St Kevern are grown, but even these are not immune. The avoidance of fresh manure or excessive nitrogen is essential and the early lifting of the bulbs is preferred. These should immediately be sprayed with a suitable fungicide and dried rapidly in a good air-flow by using electric fans. Storage should then be at a low temperature of 17-18C (62-64F) with planting in late September or early October when soil temperatures are lower. Bulbs in storage should be inspected regularly and soft ones destroyed.

 



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