A slow-spreading pest that gradually destroys plantings of Narcissus and some other bulbs.
Hosts
Daffodils (Narcissus), snowdrops and bluebells.
Symptoms
Infested plants produce stunted growth with yellowish foliage. If the bulb is cut in half transversely, complete or partial rings of brown dead tissue can be seen where the eelworms have been feeding. Infested plants die, causing bare patches in Narcissus plantings that become increasingly larger in successive years.
Biology
The microscopic eelworms live and feed within the bulbs and foliage. They spread to other plants by foliage contact or by eelworms migrating through the soil. Their spread in this way is usually no more than 1m (3ft) per year.
Control
No chemical controls for eelworms are available to amateur gardeners. Buy good quality bulbs from reputable suppliers to avoid introducing this pest into a garden. If eelworm is discovered, dig out and destroy the affected bulbs and any other host plants growing within 1m (3ft). Hot water treatment of the dormant bulbs can be attempted, although the need to hold the water temperature at 44.5ºC (112ºF) for three hours requires an insulated tank with a thermostatically-controlled heater. Too much heat will damage the bulbs, while insufficient will allow eelworms to survive.
Andrew Halstead