Advice
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Narcissus leaf scorch
Hosts
A particular problem on Narcissus, but also on Hippeastrum, Galanthus, Nerine and several other bulbs.
Symptoms
A scorched or reddish-brown appearance to the leaf tips soon after emergence. If conditions are wet, this will enlarge and spread down the leaf. Leaves may be distorted.
Biology
Caused by the fungus Stagonospora curtisii. Tiny black fruiting bodies of the fungus in the dead tissues produce spores, which are spread in water.
The fungus can also be present in the outer bulb scales, from whence it infects emerging leaves. It probably also remains in the soil in dead leaf tissue, but little is known about its life cycle.
Control
Cut off and dispose of affected leaf tips as soon as they are seen. The disease is seldom serious enough to warrant chemical control in gardens, but the fungicides myclobutanil (e.g. Systhane Fungus Fighter) and penconazole (Scotts Fungus Clear) could be used as they are labelled for use against some other diseases on ornamentals; there is no information on their efficacy against leaf scorch. Note that the leaves of Narcissus are waxy and difficult to wet. If infections persist, discard the affected bulbs.