What's eating my daffodil?

Daffodils are remarkably resistant to most pests because all parts contain toxic alkaloids — deer, rabbits, and squirrels actively avoid them. The primary threats are narcissus bulb fly, narcissus eelworm, and basal rot fungus. The large narcissus bulb fly is the single most damaging pest, hollowing out bulbs so they produce only thin, grassy leaves.

A single fat, creamy-white larva bores into each bulb through the basal plate and feeds over winter, reducing the interior to rotting mush; infested bulbs produce only thin grass-like leaves with no flower. Firm soil around bulb necks after the leaves die back (the fly lays eggs in the holes); cover beds with insect mesh in May–June during adult flight; remove and destroy soft bulbs at lifting.

Microscopic nematodes cause distorted, yellow-striped leaves ('spikkels'), stunted growth, and rings of brown tissue visible in a cross-section of the bulb. There is no chemical control available to home gardeners; remove and destroy all infected plants and surrounding bulbs; do not replant narcissus in the same site for at least 3 years.

Although daffodil foliage is toxic and largely avoided, slugs will occasionally feed on emerging shoots and damage developing buds at soil level in wet springs. Apply iron phosphate pellets in early spring around emerging shoots; improve drainage; lay grit mulch around bulb planting areas.