Linseed [Linum usitatissimum]

Pest profile

About the pest

It is a hairless, annual dicotyledon, up to 75cm tall. The plants have slender stems and spear-shaped leaves. The large, usually blue, flowers have 5 petals.

Key features

Young plant: The three-veined leaves are well spaced and needle-shaped.

Flowers: All the sepals are pointed and the petals fall off early in the afternoon.

Biology

Linseed and flax are different cultivars of Linum usitatissimum. The tall form, flax, is rarely grown for linen fibre. The short form linseed is the usual crop grown to produce linseed oil. Both can occur as crop volunteers, generally in the season following the crop. Autumn-germinating plants may be killed by winter frosts.

Symptoms & Diagnosis

Life cycle

Seed weight: 8 mg

Seeds/plant: <1 year

Treatment

Management

Control can be helped by a stale seedbed after the crop is harvested to encourage predation and germination of seeds. Linseed is surprisingly tolerant of a wide range of herbicides but may be controlled with some hormone herbicides.